Half of the nearly 600 Americans who die from hypothermia each year are age 65 or older, according to a report from the National Institutes of Health and statistics from the Centers for Disease Control and Prevention.

Hypothermia is a condition resulting from a sustained drop in a person’s normal body temperature. An elderly person is especially vulnerable because an older body has less ability to endure long periods of exposure to cold.

The elderly also are at risk for hypothermia because their body’s response to cold can be diminished by certain illnesses such as diabetes and by some medicines, including over-the-counter cold remedies. Also, being less active and less likely to generate body heat puts them at greater risk. The NIH stresses that the elderly can develop hypothermia even after exposure to relatively mild cold weather or a small drop in temperature.

Even mildly cool homes with temperatures from 60 to 65 degrees can trigger hypothermia in older people, according to officials.