Body Rhythms Play Role In Medicine

Jan. 24, 2001 -- 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.

No one knows for sure why, but one hypothesis is that progesterone levels are at their highest, which seems to boost the immune system and block cancer cells from spreading. But doctors advise not to wait for the surgery if doing so puts you at risk of having the cancer spread faster.

Hayfever’s Heyday Comes Early If you suffer from hayfever, you might notice that you tend to wake up sneezing, with a runny or stuffed nose.

The reason: the body's naturally produced chemicals, such as cortisol and adrenaline, fight off allergic reactions during the day, but by late night, the levels of these chemicals drop off. As a result, research has pointed hay fever sufferers toward taking antihistamines and decongestants at bedtime.

For asthma sufferers, late afternoon may be the best time for medication because during the night lung function of asthmatics can decrease by as much as 50 percent compared with a 5 to 10 percent decrease in those who do not suffer from asthma.

The Dental Link A woman's reproductive system, can, oddly enough, cause changes in her teeth. Changes that take place in a woman's body during puberty, menstruation, pregnancy, lactation and menopause can impact their dental health, according to reports from the Academy of General Dentistry.

Pregnant women, in particular, will see changes in their mouth during their pregnancy. Hormonal changes in pregnant women causes increased oral sensitivity, which often means swelling and inflammation of the gums, or gingivitis. Pregnant women should keep a strict regimen of brushing and flossing, and see the dentist more frequently to treat or prevent gingivitis.

Mothers-to-be aren't the only ones impacted. Younger women may notice swollen inflamed gums, cold sores and canker sores when they are menstruating. Women going through menopause may experience gum pain, burning tongue, bad taste and dry mouth, as well as bone loss due to osteoporosis. Again, it is important to tell your dentist about changes going on in your body, so that they can better handle your dental health.

The Right Time for Working Out Before you head to the gym, check your watch. Exercise specialists say that it is best to pump iron in the morning, because by the end of the day, the neck and lower back muscles are fatigued from simply holding your head and torso erect. Lifting weights late in the day can lead to injury.

But, by the same token, take the jog in the late afternoon. Aerobic workouts are best done between 4 p.m. and 7 p.m., when your heart and lungs are strongest, and your metabolic rate is highest. Fit it in before dinner, because once you have eaten your heart works hard to pump blood to the organs involved in digestion. If your schedule doesn't fit in with this one, exercising in off-hours is better than not exercising at all.