It’s late at night and you’re trying to stay awake to finish an assignment or binge your favorite show. But no matter how hard you try to fight it, you can’t help letting out a big, slow yawn. Yawning when you’re tired seems to happen automatically. But why does fatigue make us yawn so much?
Yawning is a physiological reflex that often kicks in when we need an energy boost. Understanding the science behind yawning and tiredness can help you figure out ways to minimize excessive yawning and recharge when you’re worn out.
Table of Contents
What is a Yawn?
A yawn is defined as a prolonged, wide opening of the mouth with a deep inhalation of air followed by a shorter exhalation. It involves coordinated contraction and relaxation of over two dozen face, mouth, throat and respiratory muscles.
Yawns are contagious and occur in most vertebrates. In humans, yawning starts in utero by 11-12 weeks of gestation and continues throughout life. Let’s explore what happens during a yawn:
- Activation of the jaw opening reflex and muscles like the masseter to widely open the mouth. This triggers further involuntary actions.
- Contraction of submental muscles under the chin to pull the tongue downwards.
- Stretching of the eardrums due to motion of the jaw and buildup of pressure.
- Inhalation of cool ambient air and exhalation of warmer air from the lungs.
- Tears may form to protect and lubricate the eyes which close during yawning.
- Changes in heart rate and skin conductance.
Now that we understand the physical process, let’s look at why yawning tends to occur more frequently when we’re tired.
Is This Normal?
Yawning when you’re tired or sleepy is completely normal and extremely common. In fact, research shows that being fatigued is one of the most frequent triggers for yawning.
In one study published in the Journal of Psychiatric Research, 79% of participants yawned more frequently when they felt sleepy versus when they were well-rested. So if you find yourself yawning all the time when you’re exhausted, you’re in good company. It’s the body’s natural response to low energy levels.
However, excessive yawning throughout the day could potentially indicate an underlying health issue like sleep apnea, so it’s worth paying attention to patterns. But the occasional yawning spree when you’re tired or bored is very normal.
10 Reasons Why You Yawn When Tired
There are a few explanations for why yawning often occurs when you’re worn out:
Yawning and Sleep Regulation
Yawning is closely tied to our circadian rhythms and sleep-wake cycles. Studies show yawning episodes increase right before bedtime and after waking up. The timing of yawns correlates with fluctuations in alertness and drowsiness throughout the day. When we’re tired, yawning helps indicate it’s time for sleep.
１. Yawning Frequency Follows Circadian Rhythm
Research has found that yawning conforms to a circadian rhythm, with peak times in the early morning, mid-afternoon, and evening before bed. This mirrors natural dips in alertness. Yawns were lowest during times of optimal alertness like 10am-2pm.
So yawning doesn’t occur randomly, but rather aligns with our biological clocks. When you’re tired and it’s close to your normal bedtime, frequent yawning provides a signal that sleep is imminent.
2. Yawning and Sleep Quality
Studies show that poor or inadequate sleep increases yawning the following day during periods of drowsiness. Subjects who had sleep interrupted by sounds yawned significantly more often the next afternoon.
Likewise, people with sleep disorders like insomnia and sleep apnea exhibit excessive daytime yawning. The more rested we are, the less we yawn during waking hours. Frequent yawning can be a red flag that you need more or better sleep.
3. Yawning Occurs During State Transitions
Yawning seems to occur during state transitions between wakefulness and sleep. EEG monitoring shows yawning before and after sleep coincides with changes between cortical states.
As you become sleepy and transition from alertness towards sleep, yawning helps indicate that shift. Upon waking up in the morning while still groggy, yawning signals the flip from sleep back to wakefulness.
Physiological Reasons for Tired Yawns
Aside from yawning’s relationship with sleep cycles, there are several physiological reasons yawning tends to increase when you’re tired and fatigued:
4. Improves Oxygenation
Each yawn brings a large influx of oxygen rich air into the lungs and circulatory system, while expelling carbon dioxide. This can provide a boost of alertness.
When tired, oxygen levels may drop. Yawning acts to counteract that effect and increase oxygenation of the blood to stimulate wakefulness.
5. Enhances Blood Flow to the Brain
Along with oxygenation, yawning improves circulation to the brain. The deep inhalation encourages greater blood flow. Opening of the eustachian tubes equalizes pressure in the middle ear to promote fluid drainage.
Augmented blood flow to the brain from yawning may help combat lowered mental alertness when tired. The surge of fresh blood containing oxygen and glucose to the brain can increase wakefulness.
6. Regulates Brain Temperature
Yawning may serve as a mechanism to cool down your brain temperature when it becomes too high. Brain and body heat tends to increase before sleep and yawning helps release that pent up heat.
One study found that placing subjects in warmer rooms increased yawning. The large influx of cooler air while yawning has a cooling, refreshing effect that can boost mental clarity.
7. Stimulates the Senses
The powerful stretching involved in yawning activates facial muscles and nerves that stimulate key sensory areas. The wide jaw opening and eye squeeze combine to block external stimuli and temporarily shift focus inwards.
This withdrawal from sensory input may help briefly recharge the senses to increase focus when tired or restless. The inward shift of activation reboots your alertness.
Psychological & Social Triggers
Along with physiological reflexes, there are psychological and social influences that make us yawn more when we’re bored or drowsy:
8. Boredom
Think of sitting through a tedious lecture or meeting when you start yawning repeatedly. Being disengaged mentally seems to be a potent trigger for yawning. Boredom that fails to stimulate your focus and concentration can induce yawning.
Performing monotonous tasks that cause mental fatigue and boredom increases yawning as well. Yawns during boredom may signal your brain needs stimulation to stay alert.
9. Social Contagion
Seeing or hearing someone else yawn often makes you automatically yawn too. Yawns are contagious. We unconsciously mirror the behavior, especially when tired or bored at the same time. One study found nearly 75% of participants yawned after seeing videos of other people yawning.
So in groups when individuals are bored or sleepy, contagious yawning spreads rapidly. This inadvertent social mimicry likely evolved to communicate drowsiness and readiness for rest within groups.
10. Psychogenic Yawning
Think about when you yawn in anticipation before an event, like giving a public speech or presentation. These psychogenic yawns aren’t triggered by fatigue but by psychological stress, anxiety or nervousness.
The anticipation kicks your sympathetic nervous system into gear, increasing respiration. Yawning may help counterbalance that response and reduce stress.
Effects of Excessive Yawning
While the occasional yawn is harmless, excessive yawning can contribute to:
- Irritability from fatigue
- Headaches from overworked facial muscles
- Disrupted sleep from lower oxygen levels
- Social stigma of looking bored or unprofessional
- Reduced work performance and concentration
Chronic excessive yawning should be evaluated for potential underlying causes like sleep disorders, anxiety, or medication side effects.
Ways to Minimize Yawning When Tired
Here are some tips to help reduce excessive yawning when you’re exhausted:
- Take a power nap – A 10-30 minute nap can help refresh you and reduce yawning needs.
- Do light exercise – A brief walk, stretch, or jumping jacks can energize you.
- Snack on crunchy foods – Foods like nuts or carrots require chewing and can deter yawning.
- Chew gum – Chewing gum keeps the mouth active, which makes yawning less likely.
- Stay cool – Yawning cools the brain, so staying in a cool room can help.
- Increase alertness – Splash cold water on your face, turn on bright lights, or listen to upbeat music.
- Take a caffeine break – A cup of coffee or tea can provide a temporary energy boost to fight yawning.
Creating a bedtime routine, managing stress, and consulting a doctor can also minimize excessive tired yawning.
Conclusion
Next time you find yourself yawning every few minutes when exhausted, remember it’s simply your body’s way of trying to increase oxygen, blood flow, and alertness. Paying attention to yawning frequency and timing provides insight into your sleep and energy levels.
While occasional tired yawning is totally normal, work on better sleep habits, exercise, stress management, and healthy eating to reduce chronic yawning. Give your body and brain the recharge they need to minimize fatigue and the irresistible urge to open wide and inhale deeply when you’re worn out.
Frequently Asked Questions
Q: Is yawning contagious?
A: Yes, yawning is contagious! When we see or hear someone else yawn, it can trigger our reflex to also yawn. Researchers think this helps promote group alertness.
Q: Can you stop yourself from yawning?
A: It’s very challenging to stop a yawn once the reflex is triggered. Clenching your teeth or tightening facial muscles might delay it briefly. But it’s difficult to override the involuntary reflex.
Q: Is excessive yawning a sign of illness?
A: Frequent yawning throughout the day can potentially indicate an underlying health issue. Check with your doctor if you yawn persistently without feeling tired.
Q: Do yawns provide any health benefits?
A: Yes, yawning seems to boost oxygenation, circulation, brain cooling, stretch muscles and joints, and increase alertness. This provides a quick energy boost when needed.
Q: Can drinking water help stop yawning?
A: Staying hydrated prevents dehydration fatigue which can lead to yawning. But just drinking water alone won’t necessarily curb the reflex once it’s triggered.
