According to a new study, caffeine actually disrupts our circadian rhythm, which acts as an internal clock that dictates when we should be awake and when we should be asleep.
A team of researchers from the University of Colorado shows that a double espresso can rewind our body clock by about 40 minutes and the effect can be enhanced if it is combined with bright light. Thus, if we drink coffee and are exposed to bright light for three hours, we can shift this clock by as much as an hour and 45 minutes.
“This is the first study to show that caffeine, the most widely used psychoactive drug in the world, has an influence on the human circadian clock. It also provides new and exciting insights into the effects of caffeine on human physiology,” stated Kenneth Wright, a representative of Colorado’s Department of Integrative Physiology.
In order to reach such conclusions, the researchers monitored five people for 49 days. The participants were asked to come to the laboratory where the experiment was conducted and they were exposed to dim light and bright light, but they also took placebos and caffeine.
They also underwent blood tests and saliva tests and they were asked not to drink any caffeine or alcohol during the study. The researchers afterwards collected cells from these volunteers and studied them under the microscope.
The results showed that caffeine blocks cell receptors which have the role of letting in adenosine, that has an important role in promoting sleep.
The study sheds new light into finding plausible explanations to the fact that people who drink loads of coffee cannot sleep at night. Moreover, it provides new strategies to fight jet lag.
This is not the first research that shows caffeine disrupts internal clocks. Scientists have proved that small organisms are affected by this substance just as much.
Nevertheless, further research needs to be carried out to test some of the theories promoted by the study, given the small number of participants to the study.
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