What's 'Normal'?

What's New : Your aging mother may have a fever even if her temperature reads less than 98.6 degrees. Researchers have found that older people generally have body temperatures lower than the number often considered normal.

A study conducted at Winthrop-University Hospital in Mineola, N.Y., determined that body temperature in healthy older people ranged from 94 degrees to 99.6 degrees. The researchers also found that temperature differs not only between individuals but with time of day.

Further study is needed to determine whether body temperature declines with age, according to lead researcher Irving H. Gomolin, the hospital's chief of geriatric medicine.

The study was published in the December issue of the Journal of the American Geriatrics Society.

The Evidence The study involved 100 nursing home residents and 50 individuals living in the community. Ages ranged from 65 to 98. Using electronic digital thermometers, the researchers took temperatures three times over three days from the nursing home residents; temperatures from those in the community were taken only once.

The increase in body temperature during the day was greatest in those under 75. Those who were 85 and older on average showed no significant differences over the course of a day.

Why It Matters The data suggest that heat production and conservation appear to decrease with advancing age, the researchers said.

Geriatrician Sharon Brangman said the finding could help improve care for the elderly by helping family members and caretakers determine more quickly whether a temperature reading signified a fever or was a normal fluctuation. Family members, she said, should become familiar with the individual's normal body temperature.

Body temperature, she said, should not be the only factor to consider when assessing an older patient's health. Other factors, like confusion and change in behavior, should also be checked.

--Audrey Edwards