Tuning Meds to Your Body Clock

Oct. 4 -- The human body's chemical ebb and flow, part of the 24-hour cycle known as the circadian rhythm, is now the focus of researchers who are trying to use the cycles to improve medical therapy.

Most of us are already aware of some of the ways time affects how people feel. Jet lag is a prime example, as your regular sleep cycle struggles to keep pace with adjusted bedtimes.

Yet there are many other physiological changes that take place on a daily basis that can affect your health. In fact, some of the changes experienced by the body during a 24-hour cycle are so predictable, some researchers have catalogued the effects.

For example, peptic ulcers and asthma attacks are most likely to flare up during the overnight hours, symptoms of osteoarthritis worsen over the course of the day and skin sensitivity to allergies is highest in the late evening.

"When these patterns were recognized, research was done into the biological rhythms that take part in the pathology of the disease process," says Michael Smolensky, a professor of environmental physiology at the University of Texas, Houston, and author of The Body Clock Guide to Better Health.

"Many researchers and pharmaceutical companies realized in the 1980s that by dosing medications in synchrony with rhythms in these processes that they could optimize the therapeutic benefit of medications."

Time to Heal

The time-based approach to disease treatment is known as chronotherapy, in which medications are prescribed to be taken at specific times in synchrony with the body's circadian rhythms.

Asthma treatments and heart medications have been developed with an eye on your body clock. And the approach may also help minimize the potentially toxic side effects of drugs, such as those used to treat cancer.

For instance, at a cancer clinic on the outskirts of Paris, Dr. Francis Levi equips colon cancer patients with portable, computerized pumps programmed to dispense chemotherapy drugs at specific times.