The Science of Yoga

Yoga is a commonly used term nowadays for a large number of mostly physical activities aiming at relaxing the body and calming the mind. The spread of Yoga in the west started mid 19th century mostly for intellectual purposes, but came to be a practice since mid of 20th century, and was taught by Indian yogi.

Since then, western researchers have initiated many studies on the effects of yoga on the body, essentially on the neuro-cardiovascular and respiratory functions; as well as on the mind.

What is Yoga?

The term Yoga means union and essentially means to discover our true nature. As such, yogic practices were well developed by many spiritual traditions. By spiritual we mean a truthful quest of who we are outside any religious meaning. By a unification we generally means a defragmentation process by which our whole being, body and mind, are not seen and felt as separated entities anymore.

Image from the Los Angeles County Museum of Art.

There are many ways to practice yoga, but one of the most well spread is based on what is called Asana and Pranayama. Asana means body position, and pranayama means working the energy. Asana and pranayama are also two essential methods used in meditation practice.

Yoga is also an age-old method to keep our health in balance, and this is the aim of this post to go a bit deeper into this topic.

Proven benefits of breathing practice

As a breathing practice, yoga is accessible to children and elderly alike as it does not requires special body position except to keep a back as straight as possible. The Controlled breathing is the most potent means to rebalance our energies, that means gently re-establishing a state of homeodynamic of our organs and mind allowing us to have an harmonious life. Breathing is a natural process which is controlled unconsciously by some of our brain networks, but also can be done consciously.

Breathing practice has now becomes almost routine in many hospitals, rehabilitation centers and clinics, mostly used in case of cardiac and breathing disorders, and psychological disorders [1,2,3,4]. Slow breathing practice reduce our stress hormone levels, re-establish balance between our two main nervous system: the sympathetic system is responsible for accelerating our heart rhythm, stiffening our arteries and increase our blood pressure, while the parasympathetic is responsible for decelerating our heart rhythm as well as relaxing our arteries and reducing our blood pressure.

Cardio-respiratory re-synchronization can be achieved through slow breathing technique leading to what is known as coherent breathing, a resonance phenomena discovered long ago by scientists and still studied today [5,6,7,8]. Slow breathing thus affect the cardio-pulmonary coupling and help controlling our blood pressure [9].

Deep slow breathing allows the accumulated carbon dioxide in our lungs to be evacuated. The carbon dioxide is well known to be responsible for reducing the fresh oxygen molecules to penetrates our tissues and perform the metabolic transformation of nutrients into energy, thus reducing our vital force. Slow breathing also has thus the potential to help diabetes patients [10].

Breathing is also an important part of singing and all opera singers knows well how to practice breathing, often being trained by yoga teachers. Singing and performing music has been shown to be highly beneficial for a healthy life [11].

Breathing does not stop at night sleep and is in fact a main indicator of our state of awareness. It is also well known that deep sleep is the time when our body heal itself and is also the time when breathing becomes very regular. Breathing and heart rhythms thus play together a great role in sleep process [12].

Breathing practice can take from 10 minutes to longer sessions for advanced practitioners, but the most important, is to keep a regular practice as for any exercise. It can also be performed in fitness centers as part of any cardio or strength training sessions, or in rehabilitation centers.

The Harvard School of Medicine recommends the practice of breathing to reduce stress effects.

The future

Practicing a relaxation technique such as yoga, breathing or else can be a long process where the practitioners cannot see the improvements and benefits. Thankfully, modern physiological sensors allows now to record and analyse those energies which are rebalanced during our practice, thus allowing us to concretely visualize our progresses. SATHeart is such a platform which shows your energy balance day after weeks. SATHeart is based on a holistic approach that measures not only your heart rhythms, but the complete state of your arteries and blood distribution in the various organs. SATHeart is not aimed to be worn at all time, but just at certain regular time of the day, sleep and eventually during your relaxation practice.

SATHeart has also a unique way to guide his customers to the best relaxation state using what is called biofeedback: that is we use our health measurement to audio-guide the person to this stressless state. This audio guidance is based on a unique breathing-guided therapy.


  1. Eckberg, Dwain L. “Physiological basis for human autonomic rhythms.” Annals of medicine 32.5 (2000): 341-349.
  2. Bernardi, Luciano, et al. “Effects of controlled breathing, mental activity and mental stress with or without verbalization on heart rate variability.” Journal of the American College of Cardiology 35.6 (2000): 1462-1469.
  3. Bernardi, Luciano, et al. “Effect of rosary prayer and yoga mantras on autonomic cardiovascular rhythms: comparative study.” BMJ: British medical journal 323.7327 (2001): 1446.
  4. Mason, Heather, et al. “Cardiovascular and respiratory effect of yogic slow breathing in the yoga beginner: what is the best approach?.” Evidence-Based Complementary and Alternative Medicine 2013 (2013).
  5. Steffen, Patrick R., et al. “The impact of resonance frequency breathing on measures of heart rate variability, blood pressure, and mood.” Frontiers in public health 5 (2017): 222.
  6. Fonseca, Diogo S., et al. “Gain and coherence estimates between respiration and heart-rate: Differences between inspiration and expiration.” Autonomic Neuroscience 178.1-2 (2013): 89-95.
  7. Bernardi, Luciano, et al. “Modulatory effects of respiration.” Autonomic neuroscience 90.1-2 (2001): 47-56.
  8. Vaschillo, Evgeny G., Bronya Vaschillo, and Paul M. Lehrer. “Characteristics of resonance in heart rate variability stimulated by biofeedback.” Applied psychophysiology and biofeedback 31.2 (2006): 129-142.
  9. Zhang, Zhengbo, et al. “Effects of slow and regular breathing exercise on cardiopulmonary coupling and blood pressure.” Medical & biological engineering & computing 55.2 (2017): 327-341.
  10. Bernardi, Luciano, et al. “Oxygen-induced impairment in arterial function is corrected by slow breathing in patients with type 1 diabetes.” Scientific reports 7.1 (2017): 6001.
  11. Bernardi, Luciano, Cesare Porta, and Peter Sleight. “Cardiovascular, cerebrovascular, and respiratory changes induced by different types of music in musicians and non-musicians: the importance of silence.” Heart 92.4 (2006): 445-452.
  12. Penzel, Thomas, et al. “Modulations of heart rate, ECG, and cardio-respiratory coupling observed in polysomnography.” Frontiers in physiology 7 (2016): 460.

Leave a Comment