Electric blankets may be cozy, but the can be dangerous

Dear Doctor: My wife and I sleep with an electric blanket for heat. Is there a health hazard in using it too long at night?

Dear Reader: Considering the extreme weather that froze wide swaths of the nation this past winter -- including many usually temperate areas -- it’s not surprising to learn that electric blankets have been pressed into service. Your question about safety of the devices echoes the concerns of many readers.

One of the potential risks of using electric blankets is inadvertently overheating the body. Electric bedding should never be used for an infant or someone who is immobile.

Certain medical conditions, including diabetes, can result in neuropathy, which arises from damage to the peripheral nerves. Neuropathy causes pain, tingling and prickling sensations, most commonly in the feet and hands. It can also result in numbness. Any of these symptoms can have the net effect of interfering with an individual’s sensitivity to heat, particularly while sleeping. This makes it possible to become overheated while sleeping with an electric blanket, or even suffer burns in areas of direct contact with the appliance. While there have been several reports over the years of heat stroke deaths caused by elevated core body temperatures due sleeping with an electric blanket, these are exceedingly rare.

Less dramatic but still important is the potential for heated blankets to affect sleep. Numerous studies over the decades have shown that our core body temperature drops a few degrees as we sleep. Lower body temperature has also been linked to a faster onset and better quality of sleep. By creating a continuously heated environment, electric blankets may interfere with the body’s nocturnal temperature cycles, thus interfering with sleep.

The topic that seems to generate the most controversy about electric blankets is the question of electromagnetic fields, or EMFs. These are areas of energy that are present in the natural world as well as in the man-made one. In the built world, EMFs are generated by power lines, the electric wiring within a home, wireless communication devices and equipment, and electrical appliances, including the electric blanket. The concern is that, because our bodies generate billions of tiny electrical impulses that are capable of being influenced by external EMFs, exposure may present a health hazard. Although the issue continues to generate numerous studies and an ocean of ink with impassioned arguments on both sides, a definitive conclusion has not yet been reached.

One potential compromise is to use the electric blanket to preheat the bed. Turn it on an hour or so before you retire for the night, and turn it off before getting into bed. With a snug and cozy start to the night, we think you’ll find a few layers of quilts and blankets will keep you warm until morning. In the meantime, if you do use an electric blanket, be sure it’s in good working order. Address any potential tripping hazards presented by the controls and wires, and follow the manufacturer’s directions regarding placement, maintenance and cleaning.

Eve Glazier, M.D., MBA, is an internist and associate professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and assistant professor of medicine at UCLA Health.