Ask The Pharmacist: The science of yawning

Suzy Cohen

Last week I forced myself to stay up two nights in a row to work. I certainly had work to do, but I also wanted to evaluate my brain function after sleep deprivation. The following morning, I was yawning quite a bit while sharing the story with Sam. He jokingly snapped, “Hey, stop that! You’re making me yawn!”

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I thought that was hilarious and kept my eye on him for several minutes, and sure enough, when I yawned, he yawned. Yawns are known to be “contagious,” especially if you are emotionally connected with one another. Did I get you to yawn just yet?
Saying the word out loud or reading “yawn” triggers a yawn. They’re usually satisfying in nature, and if they’re not, it is thought to be your subconscious inability to let go. One yawn lasts about six seconds and during that time, your heart probably beats faster.

“Research shows that when people get the sleep they need, they will not only feel better, but will also increase their odds of living healthier, more productive lives,” says Dr. Vasken Artinian.

A yawn does not really happen just because you’re bored or tired. I mean it could, but it doesn’t have to. For decades, doctors said it was your brain’s attempt to pull more oxygen in for the tissues. Research on animals published in The International Journal of Applied Basic Medical Research in June 2017 points to yawning as a way to drain lymph from around the brain. That’s interesting because we are only now realizing the brain actually has a lymphatic system.

We, meaning humans, yawn in the womb, and yes, it’s boring in there for sure, but around 11 to 20 weeks post-conception, it can be seen on ultrasound. Another interesting fact about yawning is that medications can cause it. For example, one of the biggest offenders is the category of antidepressants, especially the SSRIs and SNRIs like Prozac and Cymbalta respectively.

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Benzodiazepines (clonazepam, alprazolam) and opiate analgesics (hydrocodone, oxycodone, morphine) will often trigger yawning attacks -- it’s a well-documented side effect during normal treatment. It’s more apt to happen during ‘interdose withdrawal’ (the hours in-between your scheduled doses of the day), or more likely when you quit taking these drugs, which requires a long tapering process.

attacks induced from antidepressants, benzos and opiates are almost always annoying and uncomfortable. Anesthetics used to sedate you before surgery can cause yawning. And a big yawn-inducing category are the dopaminergics used in Parkinson’s such as L-dopa or Levodopa (Sinemet contains that) or Apokyn (Apomorphine).

Did you know that the complete disappearance of yawns could indicate damage to your hypothalamus? It’s specifically damage to the dopaminergic (dopamine-producing) neurons. This is why Parkinson’s patients yawn less frequently. Likewise, the effectiveness of Parkinson’s drug therapy can actually be gauged if the patient begins to yawn again.

Some researchers think you yawn more if you are depressed. I’m not really convinced of that. Confirming this is difficult because depressed folks often have insomnia, so they are going to naturally be more fatigued during the day, and probably yawn more too.

Suzy Cohen is a registered pharmacist. The information presented here is not intended to treat, cure or diagnose any condition. Visit