Body Voltage in Bed: What It Is and How to Lower It

House wiring and anything plugged into it give off an AC electric field, whether switched on or not. Think of water pressure behind a closed tap: nothing flows, but the pressure is there. The human body, being mostly water, picks up that electrical pressure much as an antenna would. Body voltage is that pickup, measured in millivolts (mV) between a person in bed and the earth. It shifts with every movement, so it is measured at the bed, where people lie still for hours.

In her measurements, an ordinary bedroom usually read about 1,500 to 2,500 mV, and around 2,000 mV was common in suburban homes wired with plastic-sheathed cable. Buildings wired in metal-clad cable, as New York City long required, could read as low as about 4 mV. With every single breaker in the house switched off, beds typically fell to around 30 mV. Her goal was under 20 mV at the bed. Building-biology guidelines call under 20 mV minimal, 20 to 100 moderate, 100 to 1,000 strong, and over 1,000 very strong.

Evidence: Inspector's practice (precautionary).

• Unplug every lamp, clock, charger, heating pad and electric blanket near where your head rests. Use battery clocks and lamps instead.
• Move cords and power strips away from the bed, and never run wires under it.
• A metal bed frame works like an antenna and can add to the voltage.

If unplugging things makes the reading go up rather than down, the wiring may have a fault such as reversed polarity. That calls for a licensed electrician.

To find which circuits reach the bed, one person watches a meter at the bed while another works the panel: all single breakers off, then each one on by itself, noting the reading. Circuits that matter can be kept off at night where practical. Surprises are common: in one home, a basement circuit was affecting a second-floor bedroom.

Safety rules, without exception:

• Only flip breakers. Never remove the panel cover or touch wiring. Never switch off the main.
• Skip the test if the home has an old fuse box, or the panel shows rust or water stains. Call a licensed electrician.
• Wear rubber-soled shoes on a dry floor and use one hand.
• Warn the household, shut down computers, tell any alarm company, and check afterward that the refrigerator and freezer restarted; never switch off a circuit that powers a CPAP, oxygen concentrator, medical pump or other powered medical equipment while it is in use. Old breakers sometimes will not reset.

Any repair, relay switch or rewiring is work for a licensed electrician.

The inspector's own father was a restless sleeper whose bed read about 2,000 mV. After she placed a grounded cloth under his mattress cover, readings dropped by about 90 percent and he slept peacefully. When grandchildren at play pulled the wire loose, his thrashing returned, and it eased again once she reconnected it. (She later grew more careful about grounding the body itself and put removing sources first.) In another case, a five-year-old stopped wetting the bed after the voltage at her bed fell from 7,000 mV to 14 mV. A woman who could sleep anywhere but home had 18,000 mV at her bed; unplugging a heating pad and a headboard lamp brought it to about 250 mV, and she slept.

Evidence: Inspector's practice (precautionary). These are individual reports, not controlled studies. Restless sleep and bedwetting have many causes, so they deserve a doctor's look too. If you snore, wake up gasping or still feel unrefreshed after a full night, ask your doctor about a sleep study; sleep apnea is common, treatable and easy to miss.

She also leaned on a 1996 University of Toronto study of Ontario Hydro workers, which reported cancer risk (mainly leukemia) at about 1.6 times the expected rate for magnetic fields alone, but up to about 11 times for electric and magnetic fields together. She noted herself that workers' exposures may not compare with a bedroom.

Evidence: Mixed or limited evidence.

Current guidance: IARC classes extremely low frequency magnetic fields as possibly carcinogenic (Group 2B, 2002) and found the evidence on electric fields too limited to classify (Group 3). No health agency sets a limit for body voltage. WHO accepts that people who report electromagnetic hypersensitivity have real and sometimes disabling symptoms, but blinded provocation studies have not shown the fields to be the cause.

This page is for education only. It is not medical, legal or engineering advice. The inspector whose work this builds on was an environmental consultant, not a physician. Talk with your doctor about health concerns, and use licensed professionals for electrical work and large mold jobs. Products, prices and labs mentioned reflect the years they were recorded and may have changed.

Source: the field work of environmental inspector May Dooley, MS, MA, CMC

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