Changes in Pulse Rate, Respiration Rate, Blood Oxygenation, Perfusion Index, Skin Conductance and Their Variability Induced During and After Grounding Human Subjects for Forty Minutes

Gaetan Chevalier, Member, IEEE

Abstract – It has been claimed that grounding normalizes physiology, electrophysiology, cortisol and improve sleep. To study grounding more thoroughly, a multi-parameter double-blind study was performed on 14 men and 14 women (age range: 18-80). This report presents results for five parameters measured during 2-hour grounding sessions, leaving time for signals to stabilize (40 minutes) before, during and after grounding. The parameters were: skin conductance (SC), blood oxygenation (BO), respiratory rate (RR), pulse rate (PR), perfusion index (PI). Sham 2-hour grounding sessions were also recorded with the same subjects as controls. Statistical analyses were performed on four 10-minute segments: before and after grounding (sham grounding), before and after un-grounding (sham un-grounding). There was an immediate decrease in SC at grounding and an immediate increase at un-grounding on all subjects. RR increased during grounding, and the effect lasted after un-grounding. RR variance increased immediately after grounding then decreased. BO variance decreased during grounding, followed by a dramatic increase after un-grounding. PR and PI variances increased toward the end of the grounding period, and this change persisted after un-grounding. These results warrant further research to determine how the body is affected by grounding. Grounding could become important for relaxation, health maintenance and disease prevention.
Index Terms –Blood oxygenation (BO), pulse rate (PR), heart rate, grounding, physiology, perfusion index (PI), respiration rate (RR), skin conductance (SC), blood volume pulse (BVP).
Footnote – Manuscript received January 21th 2009. This work was supported by Earth FX, Inc., Palm Springs, California.
Gaetan Chevalier is visiting researcher in the Developmental and Cell Biology Department, University of California at Irvine and a consultant for Earth FX Inc. (phone: 760-815-9271, fax: 858-225-3514, email: chevalier.gaetan@gmail.com).

I. INTRODUCTION
Recent reports have suggested that grounding people might have benefits other than protection against electrocution or protection of electronic components they handle from electrostatic sparks. Benefits reported include: improved sleep, normalization of cortisol circadian rhythm [1], reduced stress, normalization of electrophysiological measures such as electromyography (EMG) and electroencephalography (EEG), and changes in physiological parameters such as blood volume pulse (BVP) [2].
This research project was designed to: 1) investigate the validity of previously reported physiological and electrophysiological results regarding immediate effects after grounding; 2) find out how the body reacts to grounding for the first 40 minutes after grounding; and 3) discover what happens to body functions the subsequent 40 minutes after un-grounding. Forty (40) minute periods were chosen because: 1) in pilot projects it was found that signal stabilization can take up to 30 minutes; 2) anecdotal reports with thermography equipment showed a marked decrease in acute or chronic inflammation after 20-30 minutes of grounding. In this study, particular attention has been given to prevent any possibility of electrical ground loops by choosing recording equipment optically isolated from the data acquisition system. The current research project included all the physiological and electrophysiological parameters reported previously (except for cortisol). Parameters not reported in previous research papers were also recorded. This paper focuses on five (5) parameters: skin conductance (SC), perfusion index (PI), pulse rate (PR), respiration rate (RR) and blood oxygenation (BO). Results for other parameters will be presented in future papers. Statistical procedures were designed to evaluate both the average values of the parameters measured as well as their variability.

II. MATERIALS AND METHODS
A. Subjects
A total of thirty-two (32) relatively healthy subjects participated in this study. Four (4) subjects were eliminated, one was a screening failure and three subjects were dropped because apnea rendered their data unusable. Accordingly, the results presented in this paper are for 28 subjects [48.11 ± 14.48; average age ± standard deviation (SD)]. These subjects were equally divided among men and women: 14 men (45.43 ± 13.62, range 25-66), and 14 women (50.79 ± 15.32, range 26-78). Informed consent was obtained from all subjects prior to their participation. This study was approved by the Biomedical Research Institute of America, an independent Institutional Review Board located in San Diego, California.
Subjects served as their own controls in that each subject’s data from a 2-hour grounded session was compared with another 2-hour session when not grounded (non-grounded or sham-grounded session). The sequence of the grounding vs. sham grounding for each subject was assigned randomly; the only requirement was that 50% of the grounding sessions were in the first session. This randomization process was designed to ascertain that the measured effects were due to grounding and not to artifacts produced by sitting in the same position for 2 hours and artifacts due to grounding session order or time of day. Subjects for this study were recruited by word of mouth.
Exclusion criteria were: 1) pregnancy; 2) age < 18 or over 80; 3) taking pain, anti-inflammatories medication, sedatives or prescription sleeping medication (less than 5 days prior to testing); 4) taking psychotropic drugs or being diagnosed with mental disorder; 5) recent surgery (less than 1 year); 6) documented life threatening disease (such as cancer, AIDS, etc.); 7) consumption of alcohol within 48 hours of participation; 8) use of recreational drugs.

The health status of prospective subjects was determined with a commonly used medical screening questionnaire, the Health History Inventory (HHI) [3]. The psychological wellbeing of subjects was evaluated using a Wellness Assessment Tool (WAT) developed by Maryville University [4] and pain levels and locations were noted using the McGill Pain Questionnaire (MPQ) [5].

B. EQUIPMENT AND INSTRUMENTATION
1) Recording and data processing equipment
To prevent any possibility of electrical ground loops, equipment was chosen that optically isolates the subjects from the data acquisition systems. Subjects’ PR, PI and BO were recorded using the Radical-7 from Masimo (Masimo Americas, Inc., 40 Parker, Irvine, CA). This state-of-the-art oximeter uses multiple wavelengths of light to continuously and noninvasively measure BO, PR, PI, hemoglobin, carboxyhemoglobin and methemoglobin, and to provide the most reliable probe-off detection (if the probe is not correctly positioned, a bell rings to let the experimenter to know immediately). PI with trending capability indicates arterial pulse signal strength and may be used as a diagnostic tool during low perfusion. It is equivalent to blood volume pulse (BVP). The fastest sampling rate of the Radical-7, 0.5 samples/second (s/s), was used. After each session, data recorded during the session (in the experiment room) were downloaded to a computer located in an adjacent room (the control room) via a USB cable.
SC and RR were measured from the ProCom5 Infiniti encoder, a biofeedback-type device manufactured by Thought Technology (Thought Technology Ltd., 2180 Belgrave Avenue, Montreal, QC H4A 2L8 Canada). This is a five (5) channel, multi-modality device for real-time computerized biofeedback and data acquisition. It has five protected pin sensor inputs with two channels sampled at 2048 s/s (for EEG and EMG) and three channels sampled at 256 s/s. SC and RR were sampled at 256 s/s. For data analyses, the data acquisition speed of SC and RR was reduced to the data acquisition speed of the Masimo unit by extracting one data point per 2 seconds from SC and RR recordings. SC and RR sensors pass signals to the host computer via a microprocessor-controlled encoder unit. The encoder samples the incoming signals, digitizes, encodes, and transmits the sampled data to an interface unit designed to send light impulses through a fiber optic cable. This transmission system provides maximum freedom of movement, signal fidelity, and electrical isolation. To send the signal to the host computer located in the control room, a 50 feet fiber optic cable was used.

2) Grounding System
Four (4) Transcutaneous Electrical Nerve Stimulation (TENS) type adhesive electrode patches were placed on subjects, one on the sole of each foot and one on each palm. Wires from a standard electrostatic discharge ground system were snap-attached to the electrode patches and connected to a box (Fig 1). The grounding system itself consisted of a 100 foot long (30.48m) ground cord connected to the box on one end and attached to a 12-inch (30.48cm) stainless steel rod planted in the earth outdoors at the other end. Another box with a switch in between both ends of the grounding cord was used to cut or establish the connection with the earth. The switching box was placed in the control room. The ground cord also contained a UL approved 10 milliamp fuse.

3) Environmental Requirements
There was a concern that the ground wire could act as an antenna for electric fields, particularly when the lead was disconnected from the earth. There were also concerns that the electric wiring in the walls could induce electric fields on the body. To avoid these problems, care was taken to choose a room with modern well-grounded electrical outlets (all wiring was clad in grounded electrical conduits).
To verify that the room was very quiet electrically, a voltmeter with one terminal connected to a separate dedicated ground system (a rod driven into the earth, identical to the body grounding system used in the experiment) was utilized. The voltmeter had a large (approximately ½ inch diameter) metal contact attached to the un-grounded terminal. Subjects were asked to place their thumb on this contact to measure induced body voltage with respect to the earth. Readings on the body were typically less than 5 mV AC. The voltmeter had an accuracy of +/- 0.3%.

C. Experimental Procedure
After a subject’s arrival and prior to the beginning of the first session, the study coordinator verified that the consent form had been signed and that all questions regarding the study were answered (subjects were given the consent form in advance). Next, the study coordinator asked all questions in the Health History Inventory (HHI). The study coordinator verified that the subject’s answers to HHI questions were in compliance with respect to the exclusion criteria. After making sure that the subject was qualified, the study coordinator asked the questions in the McGill Pain Questionnaire (MPQ) and the Wellness Assessment Tool (WAT) and wrote the answers. Then, the subject was asked to sit in a comfortable reclining chair located in the experiment room, electrodes were placed on the hands and feet, and the experimental session was started. All recording equipment and the switching box were in the control room which was adjacent to the experiment room. Subjects were tested one at a time (one subject per day with two 2-hour sessions per day) and seated with feet elevated for comfort and easy placement of grounding patches. MPQ and WAT questions were asked again at the end of the first session and at the beginning and end of the second session. The results of these paper and pencil tests will be presented in a future paper.
Grounding session order for all subjects was determined prior to the first day of the study. Each day, prior to the beginning of the first session, an assistant verified which session was the grounding session. This assistant (the same person every day) discretely replaced the fuse with a plastic object (dummy fuse) of the same size before the un-grounded session. This assistant was not permitted any contact with subjects. After a subject was seated in the reclining chair and electrode placement and equipment function was verified, a 40 minute segment was recorded with the switch not flipped. For all sessions (grounded and non-grounded) and for all subjects, the switch was flipped on and off at the same time (40 minutes after the start of the grounding session for the “on” position and 40 minutes later for the “off” position). The assistant in charge of replacing the fuse made sure that the person in charge of flipping the switch (the study coordinator) and another assistant helping with electrode placement did not know during which of the two sessions the fuse was replaced with the non-conductive dummy fuse. This procedure was maintained in keeping with research methodology for double-blinded studies.
Most subjects had their first session in the morning and the second session in the afternoon. A few subjects had the first session in the afternoon and the second session in the evening. To prevent any possibility of external variables, subjects were not allowed to leave the laboratory premises and lunch was provided (there was only one subject for which an exception to this rule was allowed). The total duration of the monitoring period for each session was 120 minutes. At minute 120, all recording equipment was stopped and electrodes were removed from the subject.
In order to determine times when movement artifacts might be recorded, a webcam was placed in the experiment room. An assistant noted any movement from a monitor screen in the control room. During the experiment, the study coordinator watched the computer screens in the control room to note any suspect change in monitored parameters. The assistant assigned to change the fuse was the only person during the entire experiment to know which session was the grounding session for each subject. He kept that information confidential until the completion of the testing phase of the study (after the last subject had been tested). At the end of the testing phase, this information was given to the principal investigator (the author).
Table I shows a summary of the periods in a session. During the first period, referred to as buffering, the subject and instruments were prepared and tested. During the second (control) period, the first 40 minute period, baseline data were recorded. At the beginning of the next period, the second 40 minute period, referred to as the experiment period, the switch was flipped on. At the end of the experiment period, the switch was flipped off. After yet another 40 minutes of post-experiment study, the experiment was stopped. This process allowed enough time for signals to stabilize, leading to at least 10 minutes of stable data at the end of each period.

D. Data Analysis
Statistical analyses where planned with five (5) purposes in mind: 1) to see if there are statistically significant differences immediately after grounding as previously reported; 2) to verify any statistically significant change after stabilization of the signals; 3) to discover if there are any effects after un-grounding; 4) to find out if there are any differences between the grounded sessions compared to the non-grounded sessions; and 5) and to determine if there are any changes in the drift or variability of the physiological parameters after grounding.
To accomplish the first purpose, for each parameter, means and SDs of the first 10 minutes of the grounded period (first 10 minutes of the Experiment period) were compared with means and SDs of the 10 minute period immediately before grounding (last 10 minutes of the Control period). For the second purpose, means and SDs of the last 10 minutes of the grounding period (last 10 minutes of the Experiment period) were compared with means and SDs of the last 10 minutes immediately before grounding (last 10 minutes of the Control period). To test for the third purpose, means and SDs of the first 10 minutes immediately after un-grounding (first 10 minutes of the Post-Experiment or Un-Grounded period) were compared with means and SDs of the last 10 minutes of the grounded period. For the fourth purpose, means and SDs of each period of a grounded session were compared with the corresponding period of the non-grounded session. For the fifth purpose, variability and slope of the parameters was tested for statistically significant trends.
In keeping with standard statistical procedures for single-factor fixed constants experiments [6], analysis of variance (ANOVA) was used to compare the means of several treatment groups at once. The hypothesis being tested is that there is no difference in means between treatment groups. This statistical model assumes homogeneity of error variance. As an example, ANOVA was used to test the hypothesis between all treatment groups in assessing respiratory rate (RR). The 8 treatment groups (intervals) taken from RR recordings for statistical analyses are: 10 minutes at the end of the Control period (C10), 10 minutes at the beginning of the Experiment period (E10), 10 minutes at the end of the Experiment period (E30), 10 minutes at the beginning of the Post-Experiment or Un-Grounded period (U10); each treatment group existing for both grounded and non-grounded sessions. Each parameter has these 8 treatment groups. The probability level p = 0.05 was used as the level of significance of all statistical tests.
After ANOVA, paired t-tests were computed to determine which pairs of treatment groups were significantly different both in terms of statistical means and standard deviations. Theoretically, to do all pair-wise mean comparisons between the 8 treatment groups of a parameter would necessitate performing 28 t-test calculations. However, because only a limited number of comparisons were meaningful, not all pairs were compared. For each parameter, only twelve comparison pairs were of interest. This kept the number of t-tests to a manageable level. Because subjects were their own controls, the direction of the outcome could not be predicted, so two-tailed paired t-tests were performed. Finally, Chi-square tests were used to evaluate the changes up and down noted during grounding or un-grounding sessions for significance.

III. RESULTS
An example of a grounded session recording for a typical subject is presented in Fig. 2. Data points for each parameter are sampled every 2 seconds. Hence, there are 300 data points per 10 minute segment for each parameter. In this example, the subject was grounded at 17:03:00 and un-grounding at 17:43:00. The immediate decrease in SC at grounding and immediate increase at un-grounding are clearly visible. This pattern was observed for all 28 subjects without exception. One can note that both RR and PR are relatively high in Fig. 2 (average RR ? 25; average PR ? 85), while BO is slightly low (average BO ? 97%; a few subjects were consistently at 100%; healthy people are usually between 98% and 100%). This subject experiences mild asthma episodes from time to time (not every day and not the day of the experiment). Fig. 3 presents the same parameters during a non-grounded session for the same subject. No abrupt change in SC is visible when the switch was flipped on at 13:50:00 or off at 14:30:00.

A. Averaging by Subject
In this averaging method, the 300 data points per 10 minute segment were averaged and that was used as one data point for a treatment group. This process was repeated for the 28 subjects giving 28 data points per treatment group. For example, to form treatment group C10 for the grounded session of RR, the average of the 300 data points from the 10 minute segment of RR just before grounding was calculated for a subject. This process was repeated for the 28 subjects, resulting in 28 mean data points for the grounded session C10 treatment group of RR.

1) ANOVA
Before proceeding with ANOVA, homogeneity of variance was tested using Hartley’s Fmax test [6]. The null hypothesis is that variances between treatment groups are not different. Fmax was calculated on all 8 treatment groups of a parameter (for 8 treatment groups, degrees of freedom df = 27, and p = 0.05, Fmax = 3.30). Since there was no statistically significant result for these Fmax tests, homogeneity of variances was confirmed for all 5 parameters tested.

2) T-tests
Despite the lack of significant results from ANOVA, it was decided nevertheless to proceed with t-tests for the following reason. Treatment groups were derived from the same sample (treatment groups came from the same subjects). T-tests can take that fact into account by using t-tests for paired groups. This capability of t-tests makes them more powerful than ANOVA for treatment groups derived from the same sample.
Table II presents t-tests performed to test the null hypothesis that there was no difference in means between pairs of treatment groups. Comparison pairs were: 1) within sessions E10-C10, E30-C10, U10-C10, U10-E30 (for grounded and non-grounded sessions); 2) between sessions (not normalized) C10-C10, E10-E10, E30-E30, U10-U10; 3) between sessions (normalized) E10-E10, E30-E30, U10-U10. The third series of comparison pairs is of particular interest since the normalization process eliminates any difference in baseline readings (C10s). In the normalization process, the difference between C10 treatment group means for the grounded and non-grounded sessions is subtracted from every data point of the grounded session C10 treatment group.
This procedure effectively brings the C10 treatment group mean for the grounded session to the same value as the one for the non-grounded session. This procedure is repeated for E10, E30 and U10 of the grounded session. The end result is that this normalization procedure removed any extraneous effects that made the grounded and non-grounded sessions different (other than the effects due to grounding). Because of the study design, any significant result obtained for this third series of t-test comparisons can only be interpreted as a real difference between grounded and non-grounded subjects.
Looking Within Sessions and for Grounded sessions in Table II, one can see that 3 treatment group mean comparisons have a probability value below the level of significance (p < 0.05). These are: U10-C10 for PI (p = 0.049), E30-C10 for BO (p = 0.045), and U10-E30 for SC (p = 0.044). One can observe that there are 4 treatment group mean comparisons with a probability value below the level of significance for the Non-Grounded sessions. These are: E30-C10 for BO (p = 0.013), U10-C10 for BO (p = 0.040), E30-C10 for SC (p = 0.018), and U10-C10 for SC (p = 0.012). Turning to the Not Normalize columns of the Between Sessions section of Table II, only one treatment group pair comparison has a probability value below the level of significance. This comparison is E30-E30 for RR (p = 0.016). This last result means that the respiration rate was significantly higher for the last 10 minutes of the grounded period for grounded subjects as compared to the same time period for non-grounded subjects. Confirming this conclusion is the results for the Normalized treatment groups. In effect, the only significant differences are for RR E30 (p = 0.002), the last 10 minutes of the grounding period and U10 (p = 0.018), the first 10 minutes of the un-grounded period. According to these results, RR is higher not only at the end of the grounding period, but RR keeps being higher for the first 10 minutes after un-grounding. In Table II (as well as all tables of this paper), probability values between 0.05 and 0.10 are also presented as potentially suggestive results for future studies.
When the difference between only two variances is tested, one can use F-tests [7]. Since an F-test between two groups is equivalent to a t-test for independent means [6], one can test the difference between two SDs with a t-test as an equivalent to testing the difference between two variances with an F-test. For the same reason as mentioned previously with t-tests for testing differences between means, t-tests are more powerful that F-tests for the purpose of testing differences between variances in this case. Consequently, to find difference between two variances, it was decided to perform t-tests on SDs.
Looking within sessions for Grounded sessions in Table III, five SD comparisons gave a t-test value below the level of significance. These are: E10-C10 for PR (p =0.021), E30-C10 for PR (p =0.041), U10-C10 for PR (p =0.002), E10-C10 for BO (p =0.042), and U10-C10 for BO (p =0.025). For the Non-Grounded sessions, the four SD comparisons below the level of significance are: E10-C10 for PR (p =0.037), E30-C10 for PR (p =0.003), U10-C10 for PR (p =0.007), and E10-C10 for PI (p =0.027). Notice that most of the significant SD t-test values are with PR, both for grounded sessions and non-grounded sessions. Clearly, this increase in variance for PR is mainly due to other factors besides grounding, otherwise both groups would not get similar increase. More on the meaning of an increase in PR variance will be presented in the Discussion section. Between Sessions for Not Normalized values there are no t-tests below the level of significance. For the Normalized treatment groups, two t-test values are below the level of significance: E10 for RR (p = 0.034) and U10 for BO (p = 0.023).

3) Chi-square Tests
Performing a Chi-square test with 28 subjects with SC recordings down at grounding and zero subjects with SC recordings up (df = 1) gave a probability of less than 5.0 x 10-7 that this result is due to chance. The same result was obtained when performing a Chi-square test at un-grounding with 28 subjects with SC recordings up and zero with SC recordings down.
Although the situation with other parameters was not so clear as for SC, Chi-square tests were performed to determine if there were any differences in the number of means up or down as compared to the control period (C10) immediately after grounding (E10-C10), after 30 minutes of grounding (E30-C10) and after un-grounding (U10-C10). Differences in number of means up or down were also looked at comparing immediately after un-grounding with immediately before un-grounding (U10-E30) for BO, PR, RR and PI (df = 2). The only parameter showing a statistically significant result is RR (Table IV; p = 0.00584). After 30 minutes of grounding most of the means for the grounded session of RR were up while most of the means for the un-grounded session were down.
Another process was designed to look at the slope of the data between grounding (un-grounding) time up to 2 minutes after grounding (un-grounding). If the slope was positive it was counted up and down if the slope was negative. If the measured slope was unclear or to close to call the first 2 minutes, the process was expanded to 5 minutes and, in a few extreme cases, to 10 minutes.
Table V presents Chi-square results for BO, PI, RR and PR using that method. For BO, it is interesting to note that there is a statistically significant result (p = 0.012) at un-grounding while this is not the case at grounding. In the first few minutes after un-grounding, the grounded sessions shows a statistically significant majority of subjects’ BO recordings with a negative slope when compared to the non-grounded session for which a majority of subjects’ BO recordings have a positive slope. There are no significant or suggestive results for PI, PR or RR.

B. Averaging across Subjects
In this averaging method, instead of averaging the 300 data points of a 10 minute segment and ending up with 28 data points (one for each subject) to form a treatment group, advantage was taken of the fact that each 10 minute segment has the same number of data points, to end up with 300 data points per treatment group. In order to do that, data points at the same position in the sequence of 300 data points were averaged across subjects. For example to build C10 treatment group, the first data point (the one exactly 10 minutes before grounding) for the first, second , third,…28th subject were averaged. This average became the first data point of the new C10 treatment group. This procedure was repeated for data point number 2, 3,…300 (this last data point is just 2 seconds before grounding), ending up with 300 data points in the new C10 treatment group. This method of averaging is more powerful statistically since the degrees of freedom are based on 300 data points versus 28 data points in the previous section.
Again, treatment groups were checked for homogeneity of variance using Hartley’s Fmax test [6]. The null hypothesis is still the same (that variances between treatment groups are not different). Just as in the previous section, Fmax was calculated on all 8 treatment groups of each parameter (this time for 8 treatment groups, df = 299, and p = 0.05, Fmax = 1.43). Since all parameters presented significant results, Fmax tests were computed on 4 treatment groups of each grounded session and each non-grounded session (for 4 treatment groups, df = 299, and p =0.05, Fmax = 1.35). Significant results were obtained on all 10 sessions (Table VI). Because the null hypothesis of homogeneous variances was not confirmed, no t-tests were performed with this method of averaging.
Since Fmax tests for 8 treatment groups and for 4 treatment groups infirmed the homogeneity of variances for all parameters tested, Fmax values were computed between twelve pairs of treatment groups within and between sessions for each parameter (for 2 treatment groups, df = 299, and p =0.05, Fmax = 1.26). Table VII presents pair-wise Fmax tests for all 5 parameters. Most Fmax tests gave statistically significant results for both grounded and non-grounded sessions. This result does not tell us much other than most treatment group variances are different from other treatment group variances against which they were tested. The most interesting results come from the Between Sessions comparisons. The reason is that differences between grounded and non-grounded sessions can only be ascribed to grounding.
Looking first at RR, the control periods (C10) start with different variances but this difference disappear after about 20 minutes of grounding and stay that way for at least 10 minutes after grounding. A similar situation can be seen for SC, although the differences disappear only after un-grounding. For the other 3 groups (PR, PI, and BO), the opposite is true. Variances start out about the same just before grounding and become more and more different with time, even after un-grounding. A detailed examination of variances for RR shows that initially the control group (C10) variance of the grounded session is significantly smaller than that of the non-grounded session (0.3020 vs. 0.5353). This situation reverses for the first 10 minutes of grounding (0.3602 vs. 0.2705). So it appears that the variance of the grounded session is more stable for RR. It also appears that grounding increases RR variance significantly, at least in the first 10 minutes of grounding. This result is in agreement with the result obtained for RR in Table III, Between Sessions, Normalized values.
For SC the situation is different. For the grounded session C10 has a very low variance compared to the non-grounded session (0.0001 vs. 0.0017) and the variance stay essentially that way for E10 (0.0003 vs. 0.0016). Although still significantly different, the E30 variance of the grounded session becomes more similar to the one of the non-grounded session (0.0023 vs. 0.0037). The grounded and un-grounded session variances become very similar at U10 (0.0019 vs. 0.0016) at which time there is no statistically significant difference between the two.
For PI, grounded and non-grounded session variances are similar at C10 and E10 but become statistically different at E30 and remained that way at U10. An examination of the variances at E30 shows that the variance for the grounded session became bigger than that for the non-grounded session (0.1288 vs. 0.0877). This situation accentuated at U10 (0.1582 vs. 0.0707). A similar situation can be seen for PR, at E30 the variance for the grounded session becomes statistically larger than for the non-grounded session (0.2686 vs. 0.1694) and remained that way at U10 (0.3800 vs. 0.2581).
The situation for BO is more complex. Starting about the same for both sessions at C10, the variance for the grounded session becomes smaller than the variance of the non-grounded session at E10 (0.0157 vs. 0.0204) and even more so at E30 (0.0188 vs. 0.0285). This trend reverses drastically at U10 with the variance of the grounded session becoming much bigger than that of the non-grounded session (0.4205 vs. 0.0107). It seems that un-grounding causes a drastic perturbation in BO variance.

IV. DISCUSSION
The study revealed distinct changes in the physiological parameters that were measured.
These parameters are related to key inter-connected physiological processes involving respiration, circulation and the autonomic nervous system. The statistical analyses were designed to reveal whether or not significant changes took place in both the magnitude of the measured parameters and their variability. The study of the variability in parameters such as heart rate, respiration rate and autonomic balance have become important topics, and there is a general acceptance that these parameters are reflections of cardiorespiratory fitness. A detailed discussion of the relevance of these findings in relation to health and longevity will be the focus of a subsequent paper for the clinician.
The Chi-square test for SC, with all 28 subjects’ recordings dropping rapidly at grounding, gave a probability of less than 5.0 x 10-7 that this result is due to chance. Likewise, SC recordings for all subjects increased suddenly at un-grounding, giving the same Chi-square probability value. This is clearly a phenomenon due to grounding that cannot be explained through ground loop faults since the ProCom5 Infiniti encoder is optically isolated from the data acquisition system. From Fig. 2, one can calculate that the SC drop at grounding is on the order of ~30 nanoSiemens (nS). This is about a 10% decrease in conductance. In some subjects, the SC decrease is as low ~10 nS, but the abrupt drop is always visible on all subjects. From careful analyses of the recordings, it is estimated that this drop happens in 2 to 4 seconds. SC has long been recognized as a measure of autonomic nervous system (ANS) function [8], so the conclusion is that grounding produces a rapid change in ANS function. A decrease in SC is considered a decrease is sympathetic nervous system function (through a decrease in sweat gland secretions) or, equivalently, an increase in parasympathetic system function (since they are complementary in function), leading to a more relaxed state. The parasympathetic system promotes body repair (through rest) and digestive function [9]. Surveys report that: 1) 54% of Americans are concerned about the level of stress in their everyday lives; 2) 62% say work has a significant impact on stress levels; 3) 73% name money as the number one factor that affects their stress level; 4) 25% of workers have taken a day off from work to cope with stress; 5) 66% say they are likely to seek help for stress; 6) highly stressed teenagers are twice as likely to smoke, drink, get drunk and use illegal drugs. Stress contributes to such life-threatening problems as heart attack, stroke, depression and infection, as well as to chronic aches and pains [10]. Hence a natural method to reduce stress has important medical and social implications. Other reports show that 51% of American adults say they have problems sleeping at least a few nights each week. Almost 1/3 have trouble sleeping every night [11]. Since SC changes suggest that grounding increases parasympathetic system function, the present results support previous studies reporting reduction in stress [2] and improved sleep [1].
RR showed a significant increase during grounding (Table II, Between Groups, Normalized data). This increase in RR continued for at least 10 minutes after un-grounding (U10). Results presented in Table IV confirm that the increase in RR was due to the majority of subjects having an increase in RR at E30 and at U10 (although statistically significant only at U10). This is the opposite of what was happening to the subjects of the non-grounded session for the same 10 minute periods. RR variance increased immediately after grounding (Table III, Between Sessions, Normalized data). A more refined examination of RR variance (based on Table VII Between Sessions and original data presented in the Results section) showed that initially the variance for the control group (C10) of the grounded session was smaller than that of the non-grounded session. This situation reversed for the first 10 minutes of grounding. So the variance of the grounded session was more stable than that of the non-grounded session. Also, grounding perturbed (increased) RR variance greatly initially which then decreased with time, becoming similar to the un-grounded session variance after about 20 minutes.
Looking at Table V, Chi-square tests for BO imply that in the first few minutes after un-grounding, a statistically significant majority of subjects’ BO recordings had a negative slope when compared to the non-grounded session for which the majority of recordings had a positive slope. The negative slopes suggest a higher level of oxygen consumption after un-grounding (BO is decreasing). The Normalized treatment groups section of Table III shows that there is a statistically significant increase in BO variance in the first 10 minutes after un-grounding (p = 0.023). A similar increase in BO variance at grounding is close to being significant (p = 0.056), so a larger group of subjects could show a statistically significant increase in BO variance at grounding [this conclusion is supported by the statistically significant result for E10-C10 (p = 0.042) from the Grounded Sessions section of Table III]. From Table VII, and explanations presented in the Results section of this paper, the situation for BO variance is relatively complex compared to the variance of other parameters. Starting about the same for both sessions at C10, after grounding BO variance became significantly smaller than the variance of the non-grounded session at E10 and even more so at E30. This trend reversed drastically with the variance of BO in the grounded session being about 40 times bigger than that of the non-grounded session at U10. It seems that un-grounding causes a drastic perturbation of BO variability.
Combining observations just mentioned for BO with higher RR during and after grounding, it seems that the body consumption of oxygen increased during grounding and stayed that way for at least 10 minutes after un-grounding. From that, one can conclude: 1) un-grounding perturbs a process started during grounding; 2) this process increases oxygen consumption necessitating an increase in RR; and 3) this process does not stop at grounding but, on the contrary, uses even more oxygen just after un-grounding. The result is a decrease in BO just after un-grounding even while RR remains high. It is also possible that, after un-grounding, the body started another internal process resulting in a need for more oxygen than during grounding. It would be interesting to find out how much time it takes for the body to return to the pre-grounding RR and BO levels.
It can be seen from Table VII that PR and PI showed similar statistically significant increases in variance toward the end of the grounding period (E30), lasting at least 10 minutes after un-grounding (U10). Since PR is the same as heart rate, PR variance is the same as heart rate variability (HRV). An increase in HRV is widely regarded as an indicator of cardiorespiratory fitness. Very little or no HRV has been linked to heart diseases [12] and is used to recognize brain death [13]. It is interesting to note that the parameters presented in this study relate to the cardiovascular system, the respiratory system, and the autonomic nervous system. The rhythms taking place in these three systems are tied together both functionally and conceptually in the phenomenon known as respiratory sinus arrhythmia (RSA). The RSA, in turn, is mediated by the autonomic nervous system, specifically by vagal activity in relation to the baroreceptor feedback loop. RSA appears to be a dynamic marker of both acute and chronic stress produced by mental load, anxiety or emotional trauma. For example, heart rate does not change significantly with age, but there is a decline in HRV, which has been associated with decreased vagal tone. PR from an oxymeter does not provide the direct information on heart electrical activity that can be found from a good quality ECG. Since ECG data necessary to perform HRV analyses were recorded in this study, an in-depth analysis of HRV is in preparation for publication.
In a previous paper [2], it was reported that a statistically significant number of subjects had a decrease in BVP at grounding. Since PI is the same as BVP, and the present PI data do not show a decrease at grounding, the present study results do not support the previously reported decrease in BVP. However, there is a clear increase in PI variance during grounding that might have been overlooked previously. Since PI is related to the cardio-vascular system, there may be a correlation between PI and PR variances. This would explain the similar results obtained for PR and PI variances. A more detailed analysis of PI variability might be indicative of the level of arterial flexibility or compliance [14].
V. CONCLUSION
A combination of the information presented for SC, BO, RR, PR, and PI in this paper leads to the following hypothesis regarding what happens during grounding and after un-grounding. Within a few microseconds of grounding, the body electrical potential equalizes with the Earth potential. This grounding isolates biochemical processes inside the body from outside electromagnetic perturbations, allowing the body to perform these biochemical processes with less energy (or more efficiently since the body does not have to come up with extra energy to cancel the effects of spurious electric or magnetic fields). These electrical perturbations are ubiquitous in the modern way of life and are very substantial in homes. For example most typical bedrooms with bedside lamps induce an AC potential at the surface of the body of 1 volt or more [15]. Contact with the earth also provides access to a virtually infinite source of electrons (antioxidants are electron givers, so having access to a source of electrons like the Earth is like having access to a virtually infinite supply of antioxidants). Grounding may play a similar role for the body that a ground plays for electronic equipment. Without a ground, the voltage is not well defined and some electronic equipment (such as certain Digital Storage Oscilloscopes) do not work properly.
Current research has established that light has the most profound regulatory effect on the biological clock located within the suprachiasmatic nucleus (SCN), a bundle of neurons about the size of a grain of rice lying within the hypothalamus. The SCN takes cues from light receptors in the retina to send a signal to the pineal gland, which releases melatonin, the sleep hormone. Still it is a mystery how sighted people with certain diseases, such as Alzheimer’s and schizophrenia, have a biological clock not responding to the daylight cycle [16]. Maybe the body has developed another mechanism to stay in step with the circadian rhythm. Remembering that human beings evolved in contact with the earth for millions of years, it is reasonable to speculate that the body has developed a sensitive nervous system (probably involving both the SCN and the pineal gland) capable of sensing low frequency changes in local electric fields.
Supporting this hypothesis, there is a substantial body of evidence suggesting that: 1) diurnal variation in the natural atmospheric electric field may itself act as a weak Zeitgeber; 2) melatonin disruption by electric fields occurs in rats; 3) in humans, disturbances in circadian rhythms have been observed with artificial fields as low as 2.5 V/m. Local electric fields are very much influenced by the presence of clouds and storms. Atmospheric disturbances up to a few kV/m (fluctuating DC) during thunderstorm activity have been reported to cause an epidemic of asthma [17].
This research showed that it takes a few seconds for the ANS to adjust after grounding the body. It can be hypothesized that after the ANS adjusted, the brain evaluates the situation and, after a few minutes, gives signals to start some internal repairs which produce extra amounts of CO2, making the blood more acidic. The readjustment to a more alkaline pH necessitates an increase in breathing to eliminate extra CO2 production [18]. This extra CO2 production continues for several minutes after un-grounding or it takes several minutes for the body to eliminate the extra CO2 in the blood. In a very short time after un-grounding, the body internal biochemistry is again exposed to external electromagnetic interferences and does not benefit from the protection given by earth ground and its electrons, so it has to work harder to eliminate the extra CO2. This situation produces a temporary decrease in BO in the first few minutes after un-grounding. Eventually, the body will return to the pre-grounding condition. One can speculate that it would take more time for the body to return to the pre-grounding condition the longer the body has been grounded (but it is probably not a linear relationship).
The findings presented in this paper corroborate previous findings regarding stress reduction [2] and improved sleep [1]. This warrants more research to understand first the physiological and electrophysiological changes happening during grounding and, on a longer term, the implications and ramifications of grounding for health maintenance and/or disease prevention. This could be an important discovery to improve people’s health naturally and to cut health care costs by preventing a host of problems and diseases related to stress.
ACKNOWLEDGMENT
The author is grateful for extensive review and comments by Dr. J.L. Oshman and Dr. S.T. Sinatra.

REFERENCES
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[2] G. Chevalier, K. Mori, J.L. Oschman, “The Effect of Earthing (Grounding) on Human Physiology” European Biology and Bioelectromagnetics, vol. 1, no. 5, pp. 600-621. January 2006.
[3] American Council on Exercise, 4851 Paramount Dr., Ragsdale San Diego CA 92123.

[4] Maryville University, 13550 Conway Road, St. Louis, MO 63141.
[5] R. Melzack, “The McGill Pain Questionnaire: Major properties and scoring methods.” Pain, vol. 1, pp. 277-299, 1975.
[6] B.J. Winer, D.R. Brown, and K.M. Michels, “Statistical Principles in Experimental Design” Boston, McGraw-Hill, Third Edition, 1991.
[7] F.F. Elzey, “A Programmed Introduction to Statistics.” Belmont California, Brooks/Cole Publishing Company, Second Edition, 1971, chapter 19, pp. 243-252.
[8] D.C. Fowles, “The Eccrine System and Electrodermal Activity,” in Psychophysiology,1986, New York, Guilford Press, ed. MGH Coles, E Donchin, SW Porges, pp. 51-96.
[9] Wikipedia, the Free Encyclopedia, http://en.wikipedia.org/wiki/Parasympathetic_nervous_system.
[10] Washingtonpost.com, Facts on Stress, January 23 2007, page HE01.
[11] National Sleep Foundation, 2002 Annual Sleep Survey.
[12] Task Force of the European Society of Cardiology and the North American Society of Pacing Electrophysiology, “Heart Rate Variability: Standards of Measurement, Physiological Interpretation, and Clinical Use.” Circulation, vol. 93, pp. 1043-1065, 1996;.
[13] J . Freitas , E . Azevedo , J . Teixeira , M . Carvalho , O . Costa , A . Falcão de Freitas, “Heart rate variability as an assessment of brain death.” Transplantation Proceedings, vol. 32, no. 8, pp. 2584 – 2585, 2000.
[14] M.P. Spencer, and A.B. Denison Jr., “Pulsatile blood flow in the vascular system,” in Handbook of Physiology. Circulation. Washington, DC: Am. Physiol. Soc, vol. II, chapter 25, p. 842, 1963.
[15] R. Applewhite, “Effectiveness of a Conductive Patch and a Conductive Bed Pad in reducing
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[16] U. Kraft, “Rhythm and Blues,” Scientific American Mind, pp. 62-65 June/July 2007.
[17] D.L. Henshaw, J.P. Ward and J.C. Matthews, “Can disturbances in the atmospheric electric field created by powerline corona ions disrupt melatonin production in the pineal gland?” J. Pineal Res., vol. 45, pp. 341-350, 2008.

[18] Wikibooks, Human Physiology/The respiratory system, 2008. Website: http://en.wikibooks.org/wiki/Human_Physiology/The_respiratory_system.

TABLES
TABLE I
Instruments Preparation Monitoring Monitoring Monitoring
Period Name Buffering Control Experiment Post-Experiment
Switch Position OFF OFF ON OFF
Grounding Session ~15 minutes 40 minutes 40 minutes 40 minutes
Non-Grounding Session ~15 minutes 40 minutes 40 minutes 40 minutes

TABLE II

TABLE III

TABLE IV

TABLE V

TABLE VI

TABLE VII

TABLES CAPTIONS

TABLE I
THE FOUR PERIODS OF A SESSION

TABLE II
T-TESTS FOR DIFFERENCES BETWEEN MEANS

TABLE III
T-TESTS FOR DIFFERENCES IN STANDARD DEVIATIONS

TABLE IV
MEAN DIFFERENCE CHI-SQUARE TESTS FOR RR

TABLE V
SLOPE DIRECTION CHI-SQUARE TESTS FOR FOUR PARAMETERS

TABLE VI
MULTI-GROUPS FMAX TESTS WITH 300 DATA POINTS PER TREATMENT GROUP

TABLE VII
PAIRWISE FMAX TESTS WITHIN AND BETWEEN SESSIONS WITH 300 DATA POINTS PER TREATMENT GROUP

FIGURES

Fig. 1

Fig 2.

Fig.3

FIGURES CAPTIONS
Fig. 1: Grounding system showing patches, wires and box connecting to a ground rod planted outside through a switch (not shown) and a fuse (not shown). Similar patches and wires from the hands were also connected to the box to ground the hands.
Fig. 2: Typical recording for a grounded session showing a drop in SC at grounding (time: 17:03:00) and a jump at un-grounding (time: 17:43:00). Skin Conductance is in ?S x 200, PI in arbitrary units.
Fig. 3: Typical recording for an un-grounded session. The switch was flipped on at 13:50:00 and off at 14:30:00.

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