Pandiculate Much? The Stretching and Yawning Instinct

Stretching your body while waking up from a good sleep can feel fabulous. As you yawn you open your mouth wide for 4-6 seconds, stretch your respiratory tract and diaphragm and inflate your lungs. We call it stretching but in your body the opposing muscle groups contract together tighter and tighter until joints, limbs and trunk are fully extended and then you reach that peak in tension. The release of the tension coincides with a sense of pleasure. This coordinated stretching and yawning is an involuntary act called pandiculation.

Pandiculation may not involve your whole body, like when you yawn and stretch your arms after hunching over the laptop too long. Animals pandiculate too. Check out this chipmunk’s morning routine! You might need your yoga teacher to help you perfect your downward dog but your dog does something like this pose spontaneously after she’s been lying down. Why do humans and animals pandiculate?

One answer is that it feels good. Eating, sex and going to the bathroom all feel good because they are part of that homeostatic drive where animals are rewarded in the brain with 'good feelings' when they do things that keep them healthy and reproducing. From experimental animal models pandiculation appears to be regulated in a similar way to other basic survival instincts like eating and sex by the limbic system. Because this involuntary muscle movement is stimulated from the limbic region of the brain patients paralyzed on one side of their body due to damage in the motor cortex will still raise both of their arms when they yawn.

The likely benefits of pandiculation to our health can be divided into the yawning aspect and the stretching part. When it comes to stretching, pandiculation might maintain optimal connections between muscles and nervous system. Human embryos pandiculate from 12 weeks gestation when motor neural circuitry is being established. In adults routine pandiculation might maintain certain ranges of motion and abilities even when we don’t engage in these activities all the time.  In the short term, pandiculation after sleep might help our body transition out of a state where motor activity is inhibited in REM sleep to a state of readiness so we can react to danger.

Our muscles and soft tissues are constantly remodelling and their shapes depend on forces exerted on them and their positions. Muscles are supported by a scaffold called the extracellular matrix. Proteins in the extra cellular matrix can stick together when we are inactive, causing stiffness.  Pandiculation seems to be triggered by periods of immobility or asymmetrical positions and probably keep things moving smoothly, while also resetting limbs to their correct positions.

Yawning is a special case of pandiculation. While the stretching part of pandiculation gets your body ready for action, the yawning part is thought to get your brain ready and more alert. Yawning might occur after waking or near bedtime as an effort to delay sleep. When bored, yawning is thought to ward off daydreaming and so we can stay focused. Another benefit of yawning is cooling the brain. Evidence shows that yawning is triggered by a rise in brain temperature, not low oxygen as is commonly believed. It is thought to bring cooler blood into the brain and push warmer blood away. The cerebral spinal fluid outside the brain may also get circulated during yawning and this might flush out sleep-inducing molecules. 

The universality of pandiculation among vertebrates argues its importance to body function but there are only a handful of studies on the topic. This might change as medical researchers are finding that too much or too little yawning and stretching can be associated with disease. Can we voluntarily pandiculate? Yoga poses like downward dog and some martial arts poses have similar aspects to pandiculation as they often require a coordinated effort throughout the body. Excitement over pandiculation lead to the invention of this pandiculator in 1914, a medieval looking contraption falsely claiming to cure anything by pandiculating your limbs for you. While the pandiculator didn't work, there is a technique called Muscle Repositioning where a practitioner manipulates the soft tissues to engage the nervous system and causes involuntary pandiculation-like contractions and this may help some patients with musculoskeletal disorders.

There may be an increase in Canadians pandiculating this Thanksgiving weekend, as we try to wake up from our turkey comas.

References

Bertolucci, L. (2010). Pandiculation: Nature's way of maintaining the functional integrity of the myofascial system? Journal of Bodywork and Movement Therapies, 268-280. Get paper.

Melnick, M. Here's What Happens In Your Body When You Yawn (At Least In Theory). The Huffington Post. Retrieved October 9, 2015.

Walusinski, O. (2013). How yawning switches the default-mode network to the attentional network by activating the cerebrospinal fluid flow. Clin. Anat. Clinical Anatomy, 201-209. Get paper.

World Wide Words: Pandiculation. Retrieved October 9, 2015.

Dog Image: By Dwayne Madden on Flickr https://www.flickr.com/photos/dj-dwayne/4073057198
Sleeping Guy Image: https://pixabay.com/p-32820/?no_redirect