CWRU sleep expert says caffeine jolt not worth it in the long run

Coffee CupsIs that caffeine jolt worth the extra hours of studying or long workday?

In the long run, no, according to Michael Decker, associate professor at Case Western Reserve University’s Frances Payne Bolton School of Nursing and a national sleep expert, because of the effects of caffeine and the changes it makes to the brain.

The chemical structure of caffeine is similar to the neurotransmitter adenosine, a chemical that transfers messages for energy in the body, and especially important for putting people to sleep. Within the brain, caffeine attaches to adenosine receptors located on many cells, he said. This prevents the real adenosine molecules from attaching to those receptors, and, in turn, inducing sleep when needed.

Adenosine is generally considered an inhibitory neurotransmitter that many believe slows activity within the central nervous system, Decker explained.

Micheal Decker“When caffeine blocks the adenosine receptors,” he said, “the ‘slowing down’ effects of real adenosine are prevented.”

Once the inhibitory action of adenosine is blocked, the brain’s naturally produced “excitatory” neurotransmitters take over, Decker said.

“It’s those excitatory neurotransmitters, which are no longer properly counter-balanced by adenosine, that lead to the increased level of alertness that one feels after drinking caffeine,” he said. “Therefore, the extent that caffeine promotes wakefulness is actually determined by the person’s own brain levels of excitatory neurotransmitters.”

With that background, he said, caffeine promotes “excitation,” or faster functioning. People also perceive that excitation as enhanced wakefulness.

But, he cautioned, caffeine does not directly enhance cognitive power. It may help a person complete his or her final exam faster, but not better.

Caffeine also makes it difficult to fall asleep, Decker warned.

“Although caffeine has a maximal effect within one hour, it stays in the bloodstream for four to six hours, exerting an effect,” he said. “As sleep is very necessary to store incoming information as memory, caffeine-induced sleep disruption can impair that process.”

So, the answer to whether the caffeine jolt pays off during final exams or for a late-night work session?

Caffeine may help a person stay awake longer, Decker said, but potential loss of recall associated with lost sleep, coupled with rushing through an exam too quickly, may outweigh any benefit.