Did you know that having a mammogram at the right time in your menstrual cycle can improve its accuracy? That changing the hour at which you take asthma or blood-pressure medication may help you feel better? That you will get more from your workouts by hitting the gym at one hour instead of another?
Most of our bodily functions–digestion, respiration, hormone production–fluctuate over the course of a day, month, and even year, because of the ways we respond to light, darkness, temperature, activity, and sleep. In an exploding field called chronobiology, researchers are learning how to treat disease with these biological rhythms in mind. Following our body clocks, they’re finding, is an important part of keeping ourselves well. Here’s how:
Schedule your mammogram within two weeks after the start of your period. That’s when you have the best chance of getting the most accurate reading, according to a number of studies, including a recent One of some 2,500 women conducted at the Fred Hutchinson Cancer Research Center in Seattle. Women who wait until the second half of their cycles, the study found, are twice as likely to get false reassurance, meaning the mammogram missed a cancer. During those two weeks, increased levels of the hormones estrogen and progesterone cause fluid retention and trigger breast-cell growth, which can obscure any abnormalities. Also, your breasts are more tender at this time, and the discomfort makes it harder for the technician to sufficiently compress the breast for the clearest reading.
Because it’s also more difficult to feel lumps when breasts are swollen, experts advise doing self-exams about five days after you begin menstruating, when the breast fluid has drained.
If you need breast-cancer surgery, by to have it during the third week of your menstrual cycle. Studies show 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 ten years. Why? No one knows for sure, but it could be because progesterone levels are at their highest, which seems to bolster the immune system, helping to stop cancer cells from spreading. (If your doctor advises against delaying, however, then don’t; the benefits in waiting for the optimal day for surgery, especially if you need multiple procedures, might be offset by the additional time the cancer is given to grow, cautions Ruby Senie, Ph.D., of the Joseph L. Mailman School of Public Health at Columbia University and one of the pioneer in this field.)
Have hay fever? Take antihistamines and decongestants at bedtime. The misery caused by nasal allergies follows a daily pattern, explains Monica Kraft, M.D., a researcher at the Cad and Hazel Felt Laboratory for Adult Asthma Research at the National Jewish Medical and Research Center in Denver. During the day, the body’s naturally produced chemicals–cortisol (an anti-inflammatory steroid) and adrenaline (a hormone that dilates the airways)–help to fight off reactions to pets, grass, mold, and other outdoor allergens. In late afternoon, levels of these chemicals begin to drop; by late night, they are at their lowest, so that’s when you need medications to kick in and block reactions to dust mites and other indoor triggers. Also, some antihistamines van be sedating, so it’s obviously smart to take them at bedtime. As for decongestants, they may or may not be stimulating,, if you find they keep you awake, take them in the morning instead, advises Dr. Kraft.
For asthmatics, late afternoon may be the best time for medication. Everyone has a 5 to 10 percent decrease in lung function during the night, says Dr. Kraft, but for asthmatics, the drop may be as much as 50 percent. The good news is that patients who take oral or inhaled steroids between 3:00 P.M. and 5:00 P.M. experience much less of a decrease–closer to the normal 10 percent. And those who take theophylline, a nonsteroidal asthma medication, get the best results if they take it between 5:00 P.M. and 7:00 P.M. These drugs take a few hours to kick in, so they’ll go to work around 11:00, when your own cortisol and adrenaline levels are at their lowest and lung function is dropping.
There’s a monthly timing issue to consider, too, says Dr. Kraft. For many women, asthma symptoms tend to worsen around menstruation (for about three days before until three days after your period starts), possibly because of hormonal shifts. If you find that’s the case for you, talk to your doctor about increasing steroid dosages starting a few days before your period is due.
Pump iron in the morning. Go for a jog in the late afternoon. “The neck and lower-back muscles work all day to hold the head and torso erect, and by the end of the day, they’re fatigued,” says Wayne Westcott, Ph.D., an exercise physiologist and fitness research director at the South Shore YMCA in Quincy, MA. That means you need to use less resistance during late-day weight training, in order to avoid injury.
Aerobic workouts, however–jogging, biking, walking–are best done between 4:00 P.M. and 7:00 P.M., when your heart and lungs are strongest and metabolic rate is highest, so you’ll burn more calories. But don’t work out any later than that, cautions David Hill of the department of kinesiology at the University of North Texas in Denton. “Exercise acts as a short-term stimulant, so it will keep you awake.” And get your aerobics in before dinner; once you’ve eaten, your heart works hard to pump blood to the organs involved in digestion.
But if these suggestions don’t fit into your daily schedule, you’re not off the hook, experts say. It’s still better to work out at a less than ideal time than to skip the gym entirely.
Schedule dentist appointments for the afternoon. You probably don’t look forward to having your teeth worked on at any time of day, but it may be less of an ordeal after lunch. Anesthesia works best 12 hours from the middle of your deepest sleep, according to Michael Smolensky, Ph.D., director of the Hermann Center for Chronobiology and Chronotherapeutics at Hermann Hospital in Houston. For most people, says Smolensky this occurs at about 3:00 P.M.
But make the appointment on a day you’re not having your period, especially if you need an invasive procedure such as an extraction or implant, advises Thomas McGuire, D.D.S., director of the Dental Wellness Institute in Sebastopol, CA. Aside from the fact that a trip to the dentist probably won’t do much for menstrual crankiness, hormonal changes when the body’s blood-clotting ability and make you more prone to gingivitis–an infection that causes sensitive, puffy gums. Plus, aspirin and other painkillers for cramps can interfere with clotting; this, combined with blood loss from menstruation itself, may lower your resistance to infection.
If you have migraines, take your medication at night. More than half of these debilitating headaches occur between 6:00 A.M. and noon. If you’re only an occasional sufferer, simply taking your medication when a headache strikes is fine. But if you regularly get morning migraines and are on preventive medications, such as Elavil or other tricyclic antidepressants, taking them at night increases their effectiveness, says Fred Sheftell, M.D., director of the New England Center for Headaches. Also, the antidepressants can have a sedative effect. It’s also smart to cut out caffeine, or–if you can’t do without it–limit coffee drinking to the morning. That way, you won’t wake with a migraine induced by caffeine withdrawal during your sleep.
And if, like 70 percent of female migraine sufferers, you find that headaches are worse during menstruation, begin taking anti-inflammatory drugs like ibuprofen or naproxen sodium a few days before your period is due and continue for three days after. Also, cut back on possible dietary triggers, such as alcohol, cheese, freshly baked bread, chocolate, and aspartame (Nutrasweet). Similarly, if ovulation is a migraine trigger, you should try following these measures for about three days at midcycle (usually day 14, counting the first day of your period as day one).
Ulcer sufferers should take medicine at bedtime. Because gastric-acid production increases in the evening, peaking between 10:00 P.M. and 2:00 A.M., most patients feel the bum just as they’re trying to get some shut-eye. Medications that stop acid secretion, such as ranitidine (Zantac) or cimetidine (Tagamet), should be taken at night to avoid the bedtime pain, advises John G. Moore, M.D., chief of gastroenterology at the Veterans Affairs Medical Center in Salt Lake City.
Make sure your blood-pressure medicine protects you in the morning. Your heart rate and blood pressure begin to rise every morning just before you wake. Although this change is harmless for most people, for those with high blood pressure, it can be problematic–even fatal. (Indeed, the chances of having a heart attack or smoke are much greater within the first few hours of waking up than at any other time of day.) Meditations such as beta blockers and calcium-channel blockers, which are administered once a day, don’t always get the morning surge under control, says William B. White, M.D., chief of hypertension and clinical pharmacology at the University of Connecticut Health Center in Farmington. Use a home blood-pressure monitor to take readings throughout the day, so you can see whether you’re protected in the morning. If you’re not–if you find that your pressure is too high–ask your doctor about taking medication more frequently. Or consider switching in the Covera HS brand of verapamil, a calcium-channel blocker you take at bedtime; the drug’s effects kick in at dawn, in sync with the start of the morning surge.
If you suffer from irritable bowel syndrome (IBS), increase fiber intake in the second half of your menstrual cycle. Women with IBS–a condition marked by abdominal cramping, gas, and changes in stool consistency–often find that symptoms worsen two weeks before the start of their periods and continue to be worse until menstruation begins. Specifically, notes Margaret Heitkemper, Ph.D., a researcher at the University of Washington in Seattle, many women, especially those with IBS, tend to be constipated during the week after ovulation. The remedy? Increase the fiber in your diet and take a psyllium-containing laxative such as Metamucil from around day 15, then stop two or three days before your period is due.