When Americans go off daylight-saving time at 2 a.m. on Sunday, they will need to set their clocks back an hour. That's easy. Harder for many is setting their body clocks back an hour.

To the rescue: Dr. Alfred Lewy, a professor at Oregon Health Sciences University in Portland and an expert on resetting biological clocks.

In April, Lewy proposed a system for speeding the adjustment to daylight time. Now he has a regimen to help people shift their body clocks the other way. It relies on the body's two main zeitgebers, or time keepers -- sunlight and the hormone melatonin, which is produced by a tiny gland at night.

Lewy's prescription: First thing Saturday morning, take a tiny dose of melatonin -- between 0.1 and 0.5 milligrams (100 to 500 micrograms). Repeat that for the next two or three mornings. (Do not drive if the melatonin makes you sleepy.) On Sunday, avoid sunlight for the first hour of daylight by wearing dark sunglasses.

The shift back to standard time, Lewy says, is tougher than adjusting to daylight time because the earlier dawn is counterproductive to the needed change in body time.

Pub Date: 10/20/98