Yoga poses can vary greatly in intensity and skill required for execution. While many yoga poses expend energy, some are intended to restore. Shavasana is a restorative pose in which the body is positioned supine (on the floor face up) with the arms at the sides, palms up, and legs slightly parted. Often performed at the end of a class and/or in between more difficult poses depending on the practice series, shavasana, or corpse pose, simply looks like someone doing nothing or taking a break though some yogis would refute this description.
I’ve seen many people (and been among them myself) either cut shavasanas short or skip them altogether at the end of class. I often hear yoga instructors recite the benefits of shavasana while admonishing practitioners to stay in the pose for as long as possible. In my over 10 years of practice, shavasana seems to be the posture encouraged the most. This is likely because some don’t see enough value in ‘just lying there’ to delay the gratification of moving on to the next thing. For many of us, before the end of our practice, our minds have already left our mats and we’re already thinking of our next meal, a shower, or some other enjoyable or needful agenda item.
What’s the point of shavasana anyway? In googling the topic, I found websites claiming that shavasana helps the body to recover bringing the heart rate and blood pressure down after more strenuous yoga poses. Before delving into this notion, let’s first breakdown what’s happening during the more strenuous yoga poses that precede shavasana. When muscles contract in yoga postures like triangle, receptors that run along each individual muscle fiber get activated and transmit signals to the brain; these receptors are called “mechanoreceptors”. The cardiovascular control center of the brain responds by sending a signal out to the heart via the sympathetic nervous system. Neurons of the sympathetic nervous system release adrenaline which binds to receptors in the heart causing the heart to beat more rapidly and with more force; this is the reason for the pounding sensation in the chest during exercise. These collective responses are beneficial and aid in the delivery of nutrient rich blood flow to the contracting muscle. Once these events occur, the effects will persist for several minutes even after the muscles stop contracting so the heart rate will remain elevated.
Theoretically, shavasana should counteract the sympathetic (fight-or-flight) response induced by more strenuous yoga poses due to the following:
1) Lying down drives blood to the body’s core region activating pressure sensors
(baroreceptors) in the torso. This results in an increase in vagal tone
(parasympathetic nervous system) due to what’s known as “reflex bradycardia.”
2) The increase in vagal tone during shavasana causes the heart rate to come down
and also causes some dilation of the blood vessels resulting in a reduction in blood
pressure. Lying in shavasana allows blood to circulate throughout the body more
easily than the standing position because the circulatory system doesn’t have to
oppose gravity to circulate blood while in this position. Thus, lying in shavasana
lightens the workload of the heart.
From both anatomical and physiological standpoints, it is logical to assume that lying in shavasana is ideal for the recovery of heart rate and blood pressure after more strenuous poses. However, in my own experience as a scientist, what seems logical doesn’t always play out experimentally when tested under lab conditions. One study compared heart rate and blood pressure during 30 minutes of recovery while participants maintained seated or lying positions after a weightlifting session. Results showed no differences in the rate of recovery for heart rate or blood pressure between the two recovery positions. Another small study investigated heart rate, blood pressure, stroke volume (the amount of blood ejected by the heart per beat) and cardiac output (total blood flow) during a full hour of recovery after a cycling workout. Their results were similar in that heart rate and blood pressures declined at similar rates while study participants recovered while seated upright or lying down. Thus, it doesn’t appear that lying down during recovery helps the body to return to normal resting conditions any faster than maintaining an upright posture.
I do believe that holding shavasana or any act of stillness can be an exercise of mental toughness requiring discipline, restraint, and mental focus. Developing these skills can benefit us in many ways as these skills are applied to other areas of life. Perhaps this is the point of the shavasana and other benefits are yet to be explored.