Hormone cure for jet lag

Press, 30 July 1986, Page 21

Hormone cure for jet lag

Researchers at Surrey University in Britain believe that a natural hormone produced in the brain could be a cure for jet lag, following a successful trial in which 17 volunteers were flown across the Atlantic, writes Jane Neale of London Press Service. Jet lag affects many people who fly across time zones from one part of the world to another because the body’s normal sleepwake time clock, or circadian rhythm as It is known, is disturbed. Symptoms range from tiredness and wanting to sleep at the wrong time of day to nausea. In severe cases they can last for up to a week. The Surrey University researchers wanted to find a means of rapidly resynchronising body rhythms to local time and chose melatonin, a hormone secreted at night by the pineal gland, which is already known to alter these rhythms in animals. In the trial, eight of the volunteers were given carefully-timed doses of melatonin, while the remaining nine were given a dummy pill. After their return, all the volunteers' were asked to rate their jet lag on a scale marked from nil (insignificant) to 100 (very bad). None of the melatonin users rated their jet lag at more than 17, while six of the nine placebo subjects scored 50 or above. Two of the placebo

subjects rated their jet lag as insignificant, but this is consistent with the highly variable nature of the condition.

Before the trial took place, the volunteers flew to San Francisco and stayed a fortnight to adapt to local time. They were given the melatonin as a seven-day course. For the three days before the flight to London, they took a five-milligram tablet at 1800 hours local time to make them feel sleepy earlier in the day and help resynchronise them when they returned home. To complete the resynchronisation, they continued to take a tablet at their normal bedtime for four days after their return.

To check on the hormone’s effects on a whole range of body rhythms, the volunteers wore wrist meters, collected urine samples, kept a daily sleep log, and regularly recorded their mood and oral temperatures. They also had to perform reasoning and alertness tests. The results of these are still being analysed but should add important information about which rhythms are altered by the hormone.

The researchers hope to carry out further trials. These would Involve crossing more than one time zone, travelling from East to West and at different times of the year when there are different hours of daylight.