Can Grounding Reset Your Circadian Rhythm While You Sleep?

Why does cortisol timing matter so much for sleep? Cortisol isn't simply a "stress hormone" to be suppressed — it's the hormone that governs when your body expects to be awake and when it expects to rest. In a well-regulated 24-hour rhythm, it rises sharply around waking and falls to its lowest point around midnight, clearing the way for deep, restorative sleep. Push that curve out of shape — cortisol still climbing at midnight, barely rising by morning — and you get the familiar modern complaint: wired at night, exhausted by day.

Grounding — maintaining skin contact with a conductive surface connected to the Earth, typically through bedding woven with silver-coated fibres — has been studied as one way to help that rhythm find its footing again. The evidence isn't a single knockout study; it's a small but growing body of research spanning cortisol timing, sleep-quality trials, and cellular energy production. Here's what it actually shows, and where the evidence is still thin.

What Did the Original Cortisol Study Find?

The foundational study here is Ghaly and Teplitz's 2004 trial, published in the Journal of Alternative and Complementary Medicine. Twelve participants with self-reported sleep disruption, pain, and stress had their salivary cortisol measured every four hours across a 24-hour period, then slept on conductive mattress pads for six to eight weeks before being measured again.

The baseline readings were chaotic — some participants had cortisol spiking at midnight, others had flat, exhausted-looking curves all day. After the grounding period, profiles shifted back toward the expected pattern: lower at night, higher in the morning. Eleven of the twelve participants reported falling asleep faster, and all twelve reported waking up feeling more refreshed.

It's a small, uncontrolled study by modern trial standards — no sham-mat comparison group — which is exactly why the more recent trial below matters.

Does More Recent Research Hold Up?

In 2025, researchers at Kyung Hee University ran a considerably more rigorous test: a randomised, double-blind, placebo-controlled trial published in Advances in Integrative Medicine. Sixty participants were randomly assigned to sleep on either an active grounding mat or an identical-looking sham mat for six hours a night over 31 days, with neither participants nor assessors knowing which group was which.

Using the Pittsburgh Sleep Quality Index, the Insomnia Severity Index, the Epworth Sleepiness Scale, and objective ActiGraph sleep tracking, the grounded group showed statistically significant improvements over the sham group in insomnia severity, daytime sleepiness, and total sleep time — plus a reduction in subjective psychosocial stress consistent with a shift toward parasympathetic ("rest and digest") nervous system activity. Because it's blinded and placebo-controlled, this is meaningfully stronger evidence than the 2004 study alone.

What Else Does Grounding Seem to Affect Overnight?

A handful of smaller studies point to effects beyond cortisol and sleep scores specifically, though each comes from a single trial and would benefit from replication before being treated as settled.

A 2011 study by Karol and Pawel Sokal found that grounding overnight was associated with increased free T4 and TSH alongside decreased free T3 — a thyroid-hormone shift the authors linked to broader metabolic changes rather than cortisol alone. The same year, Gaétan Chevalier and Stephen Sinatra measured heart rate variability (HRV) in participants who served as their own controls across grounded and ungrounded sessions, finding grounding associated with HRV improvements beyond what simple relaxation produced — an objective marker of autonomic nervous system balance.

What's Happening at the Cellular Level?

The most mechanistic explanation for why any of this might happen comes from a 2025 study by Cecilia Giulivi and Richard Kotz in FEBS Open Bio. Rather than studying sleeping humans, the researchers looked directly at isolated mitochondria — the structures inside cells that generate ATP, the body's basic unit of cellular energy — under grounded, sham-grounded, and untouched conditions.

Grounded mitochondria produced 5–11% more ATP and generated 22–33% less reactive oxygen species (ROS), a byproduct linked to oxidative cellular stress. It's an important clue toward a plausible mechanism — less electron "leakage" in the energy-production process — but it's worth being precise about what was actually measured: isolated cellular material in a lab, not a person asleep in bed. It supports a biological explanation for the sleep and hormone findings above; it doesn't independently prove them.

How Do You Ground for Sleep, Safely and Practically?

None of this research assumes anything more exotic than ordinary household wiring. Indoor grounding sheets connect only to a wall outlet's dedicated third-prong safety ground — never to the live current powering your lamps or appliances — via a copper path that runs to a grounding rod physically driven into the earth outside the building. There's no household electricity involved in the contact itself.

In practice, that means the fabric matters: bare-skin contact with a genuinely conductive surface, night after night, is what the studies above are actually testing. Our own Liquid Silver Grounding Sheet, woven entirely from silver-coated nylon, and the High-Silver Grounding Half Sheet are both built around that same principle — a dense, continuous grid of silver-coated fibre against the skin, connected to a properly earthed outlet.

The Ghaly study's six-to-eight-week timeline is a useful expectation-setter: cortisol resynchronisation, where it occurs, looks like a gradual process rather than an overnight switch.

---

References

1. Ghaly M, Teplitz D. (2004). The Biologic Effects of Grounding the Human Body During Sleep as Measured by Cortisol Levels and Subjective Reporting of Sleep, Pain, and Stress. Journal of Alternative and Complementary Medicine, 10(5), 767–776.
2. Park HJ, Lee GR, Kim Y, Kim J, Sohn M, Kim SH, Rhie SJ, Kim KR, Shim I. (2025). A randomized, double-blind, placebo-controlled study on the improvement of sleep quality with Earthing mat. Advances in Integrative Medicine, 12(3), 100458.
3. Sokal K, Sokal P. (2011). Earthing the Human Body Influences Physiologic Processes. Journal of Alternative and Complementary Medicine, 17(4), 301–308. (PMID: 21469913)
4. Chevalier G, Sinatra ST. (2011). Emotional Stress, Heart Rate Variability, Grounding, and Improved Autonomic Tone: Clinical Applications. Integrative Medicine: A Clinician's Journal, 10(3), 16–21.
5. Giulivi C, Kotz R. (2025). Earthing effects on mitochondrial function: ATP production and ROS generation. FEBS Open Bio, 15(9), 1459–1470.