A cup of coffee may be able to help with jet lag after a preliminary study finds that caffeine may be able to shift the body clock, which can help frequent travelers combat jet lag.

Researchers from the Medical Research Council's Laboratory of Molecular Biology and the University of Colorado found that when drunk several hours before sleep, coffee can affect the body's circadian rhythm or sleep-wake cycle.  For people constantly moving between different timezones, coffee may be able to help ease the transition by keeping the drinker awake during daytime.

"If caffeine was used in the evening on a consistent basis, we would expect a consistent delay," Study co-author Professor Kenneth Wright said. He adds that there's no need to worry that the delay may be permanent, as there are several other factors that can influence the body clock once coffee drinking is controlled. 

According to Wright, coffee's effect on the body clock may also explain why coffee drinkers also sleep longer than non-drinkers - in addition to being able to stay up later.  "This is the first study to show that caffeine, the mostly widely used psychoactive drug in the world, has an influence on the human circadian clock," Wright said.

The team conducted a 49-day-long study with three female and two male volunteers. The participants underwent a double blind, placebo-controlled protocol where their circadian rhythms were tested under four conditions: low light with a 200-milligram caffeine pill, low light with a placebo, bright light with the caffeine pill, and bright light with the placebo.  

Results showed that the participants who had the caffeine pill had a 20 to 40-minute circadian rhythm delay compared to those who had the placebo pill. Researchers also noted that caffeine pill takers under bright light extended subject waking period by roughly an hour and a half.

"Our findings suggest that if you take caffeine at the wrong time, it could make your jet lag on an eastward trip worse," Wright said. Using coffee to help combat the effects of jet lag can be considered, though Wright and his team believe that more study should be considered before it can be strongly recommended.

Jet lag is a form of circadian rhythm disruption that happens when a person travels to a place with a different time zone and expected sleeping and waking times than what the body is used to. The same can also happen to workers with shifting schedule.  Disturbing this natural rhythm can increase risk for cancer, diabetes, heart disease and neurodegenerative disorders such as dementia and Alzheimer's disease. 

Photo: Amanda Kelso | Flickr