Caffeine is responsible for keeping you awake but it can also take its toll on your body’s internal circadian biological clock, a new study suggests.
Kenneth P. Wright Jr., director of the Sleep and Chronology Laboratory at University of Colorado and co-author of the study said that: “caffeine affects our physiology in a way that we hadn’t really considered in the past.”
In the study, researchers took five healthy volunteers and asked them to stay in the laboratory overnight. During this time, the researchers kept an eye on the participants’ levels of melatonin. This hormone is secreted especially at night and researchers used it an an indicator of the body’s internal circadian biological clock (circadian rhythm).
The participants were asked to take a pill three hours before bed. One group took a pill that was had equivalent amount of caffeine as two espresso shots, while the other group received a placebo. The experiment was repeated again the next night when the groups switched. Thus the participants who received the placebo the first night now took the caffeine pill and vice versa.
As a result, researchers found that the caffeine pill slowed down the body’s release of melatonin by approximately 40 minutes. The body’s internal clock was affected by the dose of caffeine and in turn the start of the ‘biological night’ was pushed back, explained the researchers.
Wright says that the 40-minute setback in the release of melatonin is able to affect a person quite badly. Other research shows that he body’s release of melatonin is delayed by 85 minutes when a person is exposed to bright light before going to bed.
People who call themselves ‘night owls’ tend to drink more coffee than those who wake up early in the morning. The new study suggests that drinking coffee in the afternoon or in evening might be the exact reason why some people are ‘night owls’, Wright stated.
If timed properly, a dose of caffeine could potentially help people adjust to jet lag when they travel long distances. However, more studies need to be conducted on this topic, because there is a chance that caffeine may in fact worsen jet leg, says Wright.
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