What lies behind this seemingly simple action? Why does our body make us stretch when we yawn, even when we’re awake? Read the article below to gain a clearer understanding.
The involuntary action of stretching while yawning is known as the “contagious phenomenon” in humans. However, this behavior is not exclusive to humans; it has been observed in many different species, especially during the transition from low to high activity periods.
“Virtually all vertebrate species yawn”, Olivier Walusinski noted in 2006. He added that such behavior can be observed in infants as young as 12 weeks and “may not change throughout their lives.”
When we sleep, our muscles lose their firmness, and gravity pulls fluids in our bodies to areas along our backs. The moment we wake up, instinctively, we stretch our muscles, allowing these fluids to return to their normal positions. This stretching also helps reactivate muscles that have been resting.
Another article published in the journal Neuroscience & Biobehavioral Reviews discusses the potential origins of mammals’ sleeping patterns when awake, sunbathing, and more…
The authors write: “Post-sunbathing behavior always begins with passively exploring the surrounding environment. This behavior includes movements such as lowering the head, scanning the surroundings, stretching, and adopting muscle-stretching postures.”
Thus, yawning and stretching behavior is not only widely observed in the animal kingdom but may also be very ancient behaviors. Therefore, it is certain that performing this action serves a specific purpose.
Although to date, the specific purpose remains unexplored by scientists, there are several widely accepted hypotheses related to it.
Stretching is a relatively common behavior among feline species. Their blood pressure often drops while sleeping. Therefore, stretching may help their muscles move, increasing blood flow and assisting in detoxification.
Sleeping is a very passive ability. However, our bodies are designed for movement, and prolonged inactivity can make us sleepy in a sense.
Stretching is the way our brain checks whether all muscles are still functioning normally while reminding us that it’s time to start working.
In addition to enhancing muscle function, stretching also provides a gentle transition from sleep to wakefulness for the rest of the body.
During the day, fluids in the body tend to accumulate in the legs. At night, we often lie down—such as in a supine position—allowing gravity to pull these fluids towards the spine, torso, neck, or head. Consequently, the act of stretching helps us gently push these fluids back to their normal positions. This measure may be designed to prevent fluid accumulation from damaging muscles during activity.
It also helps relieve stiffness or tension in your muscles and joints caused by prolonged periods in one position. Over time, this helps maintain a wide range of motion even when we are not engaging in such activities.
Stretching can be a quick way to pull our bodies out of REM sleep (when motor activity is inhibited) and transition to a state of alertness, enabling us to respond to any potential dangers—much like reptiles after sunbathing.
According to a 2011 article by researcher Luiz Fernando Bertolucci published in the Journal of Bodywork and Movement Therapies, stretching is a necessary function as it prevents chronic and localized pain by relaxing and dissipating muscle spasms. Stretching helps reset communication between the brain and muscles in the body. This exchange allows the brain to operate more efficiently in preparation for the tasks ahead after waking up.
Stretching also improves blood flow and reduces stress by activating the parasympathetic nervous system (PNS)—the branch of the nervous system that handles involuntary functions like controlling heart rate, endocrine function, or digestion.
Therefore, this behavior accelerates all background processes to keep you alert and clear-headed. The level of movement also increases your heart rate—pushing blood to the muscles in the limbs.
Stretching also gives the brain a chance to recalibrate its communication with the muscles for various tasks and informs the brain about the level of muscle tension that can be safely handled.
Finally, stretching provides a pleasant sensation as it is one of the ways our body satisfies the need for homeostasis.
Animals, particularly dogs and cats, often stretch easily about 40 times a day. When you stretch, extending your limbs, joints, and muscles, signals are sent to the brain to alert the body that it is time to wake up.
