Body Rhythms Play Role In Medicine

Jan. 24 -- Many people might not know it, but research has shown that there’s a best time to take pills, an ideal hour to hit the treadmill, and a certain time of month that allows women to get the most accurate mammogram results.

Most of our bodily functions, including digestion, respiration, and hormone production, fluctuate over the course of a day, month and even year because of the ways our bodies respond to light, darkness, temperature, activity and sleep.

ABCNEWS' Medical Correspondent Dr. Nancy Snyderman told Good Morning America about a rapidly growing medical field called chronobiology. Researchers are beginning to use chronobiology to figure out how diseases might be treated with these biological rhythms in mind.

"Chronobiology says basically everything has its own clock, whether it's on a 24-hour clock or monthly clock, we know it affects tumors and how medications work, something as simple as when you get a mammogram, how things grow, how medications work," said Dr. Snyderman. "The secret is to figure out what the problem is, what the medication does, and then target it at the right time."

Mammograms’ Time of the MonthA number of studies have indicated that mammograms are more accurate when done within the first two weeks after the start of a woman's period. One recent study of 2,500 women conducted at the Fred Hutchinson Cancer Research Center in Seattle found that women who wait until two weeks after they start their period have the best chance of getting a more accurate reading.

Women who wait more than two weeks after their period starts are twice as likely miss an early diagnosis of cancer. When women wait longer than two weeks there are increased levels of the hormones estrogen and progesterone, which cause fluid retention in the breasts and trigger breast cell growth. Both of these can obscure readings, so avoid mammograms at those times.

If you need breast cancer surgery, studies have shown that it is best to have it done during the third week of your menstrual cycle. Researchers found that women whose mastectomies or lumpectomies are performed in the week after ovulation are up to four times as likely to survive, disease-free, for at least 10 years.