A 3,000-year-old ancient practice, yoga was initially conceptualized as a path to enlightenment. Today, however, most people in the West turn to this ancient practice to improve health and well-being. And they’re not wrong in doing so! Studies consistently show that the postures, deep breathing, and meditation — which we now associate with yoga — promote good health [1].

But how exactly does yoga manage to do this? The answer lies in yoga’s ability to reduce stress. Here’s more on how that works.

Yoga: An Introduction

The practice of yoga was first described by Patanjali in Yoga Sutras, an ancient text containing 196 sutras (i.e. aphorisms) on the theory and practice of yoga. In it, Patanjali outlines ashtanga, which literally translates to “eight limbs.” These are eight practices whose goal is samadhi or enlightenment. Two of these practices are yoga postures and breathing exercises. 

The original goal of yoga as we understand it is to prepare the mind and body for meditation and spiritual development [2]. However, many people today practice yoga primarily to improve health, reduce stress, or enhance well-being.  

How Yoga Benefits Health

Put simply, yoga improves health by relieving stress. 

While modern humans live longer and more comfortable lives, our lives are also chronically stressful. Under normal conditions, the human sympathetic system activates the stress response as a natural reaction to a perceived threat. Stress keeps you alert and allows you to adjust to stressful situations.

But when your body’s stress system is constantly “on”, it leads to illness. In fact, researchers now believe that 75-90% of all diseases are attributed to stress [3]. Examples include cardiovascular disease, metabolic disease, neurodegenerative disorders, and even cancer.

Opposite of your body’s sympathetic system is the parasympathetic system, which is responsible for keeping you calm and relaxed. The deep and slow breathing and gentle stretches in the practice of yoga encourage the activation of the parasympathetic system [2]. Specific ways yoga does this is by:

• Lowering heart rate and blood pressure
• Increasing blood flow to all bodily systems
• Reducing inflammation 
• Increasing flexibility and muscle tone
• Enhancing feelings of relaxation and tranquility

In short, yoga benefits health by putting the body’s many systems into better equilibrium. 

Yoga and Sleep

Sleep disorders are among the many problems resulting from uncontrolled stress and vice versa [4]. When your mind and body are under stress, your sleep becomes disregulated, fragmented, and not restorative. Such sleep further stresses your brain and body, creating a vicious cycle. 

A byproduct of practicing yoga is, unsurprisingly, better sleep [2]. Because of its ability to increase feelings of relaxation and create a balanced mental state, yoga has been studied as a safe and side-effect-free sleep aid. A systematic review and meta-analysis of 19 studies on the subject found that yoga often led to improvement in subjective scores of sleep quality [5].

Yoga Nidra, which is a form of guided meditation, was also found to reduce stress hormone levels and improve sleep quality as tested by using objective parameters [6].  

1. References:
   Ross A, Thomas S. The health benefits of yoga and exercise: a review of comparison studies. J Altern Complement Med. 2010;16(1):3-12. doi:10.1089/acm.2009.0044

1. Woodyard C. Exploring the therapeutic effects of yoga and its ability to increase quality of life. Int J Yoga. 2011;4(2):49-54. doi:10.4103/0973-6131.85485

1. Liu YZ, Wang YX, Jiang CL. Inflammation: The Common Pathway of Stress-Related Diseases. Front Hum Neurosci. 2017;11:316. Published 2017 Jun 20. doi:10.3389/fnhum.2017.00316

1. Nollet M, Wisden W, Franks NP. Sleep deprivation and stress: a reciprocal relationship. Interface Focus. 2020;10(3):20190092. doi:10.1098/rsfs.2019.0092

1. Wang WL, Chen KH, Pan YC, Yang SN, Chan YY. The effect of yoga on sleep quality and insomnia in women with sleep problems: a systematic review and meta-analysis. BMC Psychiatry. 2020;20(1):195. Published 2020 May 1. doi:10.1186/s12888-020-02566-4

1. Datta K, Tripathi M, Verma M, Masiwal D, Mallick HN. Yoga nidra practice shows improvement in sleep in patients with chronic insomnia: A randomized controlled trial. Natl Med J India. 2021;34(3):143-150. doi:10.25259/NMJI_63_19