Understanding the various effects of melatonin on the body


Light treatment device used to increase production of Melatonin in the body. Photographed for Michel Paul

Do you have trouble with the daylight saving time change? Just imagine yourself being in months of darkness, or trying to adjust to a 12-hour time change after an overseas flight. Research scientists from Defence Research Department Canada (DRDC) have spent several years trying to combat the effects of both.

“You have to regulate yourself your body’s own sleep rhythm,” said Michel Paul, DRDC research scientist. “Regulating your body’s rhythm can be achieved by appropriately-timed ingestion of supplementary melatonin and appropriately-timed light treatment. Since light is a strong stimulus to the body’s circadian clock, you must also avoid light at certain times of day to prevent sending conflicting messages to the body’s clock.”

The body has its own internal clock which controls the natural cycle of sleeping and waking hours. In other words, the body clock controls how much melatonin (a hormone that helps control sleep and wake cycles) it makes. Normally, melatonin levels begin to rise in the mid- to late-evening, remain high for most of the night, and then drop in the early morning hours.

Circadian desynchrony (loss of daily rhythms) is brought on by jet lag or shift work. It is a concern for deployed CAF members due to fatigue, which reduces alertness and work performance. This can be of special concern for RCAF pilots after long overseas flights.

The objective of the DRDC studies was to develop a schedule  for when daily treatments of melatonin and light are given at the optimum times,  would eliminate jet lag.

Based on this body of work, the CAF has recently stocked the pharmacy formulary with melatonin. The first operational use of melatonin was in support of CAF pilots operating out of Kuwait to facilitate adaptation from day to night operations.

Mobile application

DRDC has covered all of its stresses and—now there’s an app for that. The application,—available on Google Play and accessible on Android, Google smartphone or tablet—prescribes which hours of daylight to seek and which hours of daylight to avoid, as well as the optimum timing for ingestion of a melatonin pill to phase shift the body’s rhythm.

The user inputs the travel information into the app, which shows a start date, number of days to begin sleeping an hour earlier each day (or later, depending on whether circadian phase advance or delay is required), when to take melatonin each day, and when to seek and avoid light to attenuate or even eliminate jetlag.

Depending on the individual, jet lag can last several days before the traveller is fully adjusted to a new time zone.

Seasonal effects

Like jet lag, a lack of sunlight or darkness can have a huge effect on the bodies of CAF members posted to location such as CFS Alert. DRDC scientists have also researched how they can help military personnel adapt quickly to the light changes.

Research results showed winter sleep patterns changed significantly between January- June, as personnel in summer slept an average of 46 minutes less than those in winter. Circadian stress and poor mental effectiveness were more pronounced in the meteorology technicians who worked very irregular schedules.

The summer hours in CFS Alert, from April to September, posed problems because of too much daylight at night. People found it hard to sleep because their body’s production of melatonin had been suppressed by the exposure to nocturnal light.

“In the summertime, when it is daylight around the clock, personnel would be thinking ‘let’s play, it must be noon’, when it was really the middle of the night,” said Mr. Paul. “This was placing a strain on the human circadian system, which can lead to negative affect in the winter and difficulty obtaining enough sleep in the summer months, causing people to function like zombies.”

DRDC data

As a result of this research CAF now has the ability to treat military personnel prior to deployment, so they arrive in a new time zone without jet lag—and the same knowledge is now applied to help military personnel adapt to various nocturnal work schedules, especially in the Arctic.

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