Q. I yawn frequently. Is this just a sign of a lack of energy or could it be something more serious?
A. Most people assume that yawning is a sign of being tired. But sometimes people yawn when they are not tired — when someone else yawns or when you are bored, for example. And sometimes yawning becomes excessive or chronic. These types of pathological yawns can be an indication of a serious health condition. A 2009 review on the relationship between yawning and diseases noted that excessive yawning can precede migraines and certain kinds of seizures, and can occur during a stroke. But normal, everyday yawns are a different phenomenon. And why people yawn is not completely understood. But there are plenty of theories.
YOU'RE SLEEPY AND YAWNS KEEP YOU ALERT
People do tend to yawn the most when they're sleepy or tired. So what's the purpose? A 2010 review in the journal Neuroscience and Biobehavioral Reviews notes that, since yawning tends to occur during periods of drowsiness (just before sleeping, or after waking), some people have assumed that yawning arouses the sleepy body in some way.
It makes sense to think that a yawn might perk up a sleepy body: that big gulp of air, that wide-mouth stretch. But when researchers used electroencephalography (EEG) to monitor brain activity, yawns didn't seem to increase the type of brain activity that would indicate there was a heightened state of brain arousal.
YOU NEED MORE OXYGEN, SO YAWNS GIVE YOU A BIG GULP
It seems like you're taking in a big breath of air (and therefore more oxygen) when you yawn, but you're also holding your breath a bit and exhaling longer. You'd actually take in more oxygen by breathing faster than by yawning. And the 2010 review points out that during the times when a person clearly needs more oxygen — such as during exercise, or in experiments where people are exposed to air containing lower levels of oxygen — yawning does not increase.
YOU'RE REPLENISHING STALE AIR IN YOUR LUNGS WITH FRESH AIR
The 2010 review notes that a centuries-old belief has been that yawns remove 'bad air' from the lungs. Could this be the case? And what 'bad air' exists that isn't already removed when you exhale normally? It could be the residual area in the lung region. While most air is inhaled and exhaled continuously through breathing, there is always a certain amount of dead air, or physiologic dead space, in the lungs. If there weren't, every exhale might cause a collapsing of the lungs until new air filled them back up again. There is an assumption that this dead air is bad and lacks, or is low in, life-giving oxygen. As previously explained, this is probably not why yawning occurs because it doesn't seem to increase oxygen supply, and yawning rates don't increase when there is a greater demand for oxygen.
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YAWNS COOL DOWN YOUR BRAIN
Some researchers have proposed the idea that yawning somehow cools off the brain. A couple of experiments found that people yawned less frequently when they had cold packs on their head compared to when they had warm packs on their head, or that they yawned more when they were in warmer rooms compared to colder rooms. The 2010 review notes that some confounders for these study exist. Perhaps the cold ice pack increased alertness and thereby decreased yawns, for example. There is also no adequate explanation as to why air inhaled during a yawn might provide better ventilation to the brain than would regular breathing.
YAWNS ARE A FORM OF COMMUNICATION
This theory seems the wackiest, but the 2010 research review gives it the most credence. Here's why: Yawns are contagious. And that's not just in humans. Some animals, like chimps, dogs and other animals who are considered to have advanced empathic and social skills, according to the researchers, also exhibit contagious yawning. And social hierarchy seems to play a role — in some animals the group leaders initiate yawns more often than those animals beneath them, according to the study. So yawning may have some signaling function — but communicating what exactly is unclear. But then again, humans and animals also yawn when alone.
In fact, the act of yawning is a complex process and there may be many different types of yawns with many different functions. The reviewers note that there is still much to be learned about yawning.
So why are you yawning?
If you're sleep deprived like most people, it could simply be a manifestation of your chronic sleep debt. Try sneaking in an extra 30 minutes or hour each night, and make sure to catch up on weekends. Do this for two to three weeks and notice if you feel more alert during the day — and if you yawn less. And try exercising more if you feel like you're low on energy. Sometimes too little sleep and too little exercise can make you feel extra tired. If you're yawning in the evenings, perhaps you should just go to bed. And if you have chronic or excessive yawning, consult your doctor.
More from MSN Health:
- 5 Secrets to Great Naps
- How To Nap At Work AND Boost Productivity
- 6 Surprising Sleep Stealers
- Bing: How to Sleep Better
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