Caffeine is a powerful stimulant, which means it can be tempting to reach for it in the morning after tossing and turning all night. But its stimulating properties make it a double-edged sword for insomniacs.
“We think that caffeine makes us more alert,” says Orfeu Buxton, PhD, a Penn State University professor of biobehavioral health. “It actually makes us more anxious and a little more alert, and the anxiety lasts longer than the alertness.”
Caffeine is also habit-forming and tolerance-inducing — meaning you’re likely to need increasing amounts to achieve the same buzz.
Along with the 24-hour circadian cycle that governs our internal clocks, internal sleep pressure helps regulate resting and wake times. Caffeine produces alertness by latching on to the brain’s adenosine receptors; adenosine is a sedating chemical that accumulates over the course of the day and builds sleep pressure.
When we block adenosine with caffeine, it mutes one of the body’s primary cues to ready itself for sleep. This is great when we want to be awake, but it often backfires.
Once the body has metabolized caffeine, backed-up adenosine rushes in, which can lead to the all too familiar caffeine crash. When we hit that wall, we often reach for more caffeine to power through the day.
But caffeine’s half-life can be five hours or more, so if we have coffee or tea at 4 p.m., as much as 50 percent of its caffeine may still be circulating in our brain tissue and blocking adenosine receptors at 9 p.m. This sets the stage for another sleepless night.
It’s a cycle of dependency familiar to many insomnia sufferers. “Caffeine, like sleeping pills, is an example of a temporary countermeasure to insomnia that might be OK in the short term but tends to point you in the wrong direction over time,” says Buxton. (For more on caffeine’s effects, see “The Pros and Cons of Caffeine”.)
This was excerpted from “Good Night, Insomnia” which was published in Experience Life magazine.
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