Ghaly and Teplitz (2004) conducted a study with 12 subjects to investigate the effects of grounding using a conductive mattress pad over an 8-week period. They hypothesized that grounding the human body to the Earth during sleep would result in quantifiable changes in cortisol levels. To test this, they measured diurnal cortisol secretion levels and circadian cortisol profiles.
Cortisol, an arousal hormone produced in the adrenal cortex, is linked to stress, inflammation, and sleep dysfunction in humans. Normally, cortisol levels should be higher during the day and lower at night as part of the body's natural cycle. However, chronic stress can elevate cortisol levels, leading to disruptions in circadian rhythms and contributing to various health issues such as sleep disorders, increased pain, hypertension, cardiovascular disease, stroke, mood disturbances, and abnormal glucose levels (Hannibal et al., 2014; Bjorntorp, 2001).
The study’s authors also hypothesized that grounding would improve sleep, pain, and stress (anxiety, depression, irritability), which were evaluated through subjective reporting. All subjects reported sleep dysfunction, pain, and stress. Saliva tests to establish cortisol levels were administered before grounding, at 4-hour intervals over a 24-hour period to determine circadian cortisol profiles, and again at week 6. Subjective symptoms were reported daily by the participants throughout the 8-week period.
Grounding was implemented by placing a conductive mattress pad under the fitted sheets while participants slept. The researchers measured the electric field-induced voltage on subjects' bodies before and after grounding using a digital multi-meter. The subjects' average pre-grounding voltage dropped from 3.27 V to 0.007 V in bed while lying on grounded mattress pads, indicating a significant reduction in voltage due to grounding.
The results showed improvements in diurnal cortisol profiles, with significantly reduced cortisol levels during night-time sleep. The 24-hour circadian cortisol profiles of the subjects trended toward normalization. Additionally, subjective reports indicated reductions or eliminations in sleep dysfunction, pain, and stress in nearly all subjects.
Based on these findings, the researchers concluded that grounding during sleep reduces night-time cortisol levels and resynchronizes cortisol hormone secretion to align more closely with the natural 24-hour circadian rhythm. Changes were most apparent in female participants, and subjective reports also indicated improvements in sleep, pain, and stress.
