A Scientific Window into Yoga

As you probably already know, yoga is a mind-body practice that helps people reconnect with their bodies to improve health, reduce stress, create mental clarity and calmness, and improve overall well-being. But what you may not know is the actual anatomical structures and physiological functions that allow you to feel the benefits of your practice encompassing asana (the physical postures), pranayama (breathing exercises), and dhyana (meditation). Below I have broken down these concepts and will open a window into the science of yoga; giving you a better understanding of these concepts.

Asana

In Sanskrit, the term asana translates to “posture” or “pose” and can be thought to increase strength and flexibility, improve balance and coordination, and develop a strong sense of body awareness or proprioception of our physical body in space. Tuning in to our physical self not only improves our well-being but it allows us to appreciate the smallest automatic functions of our bodies. The anatomical structures and physiological functions that make up an asana within our yoga class can be thought of as the combination of bones, muscles, joints, tendons, and ligaments within the human body.

Bone

While it may not be urgent that you know the composition of what makes up a bone; it is important to know that as we age it is critical to place stress on our bones in order to make them stronger. Thus, weight-bearing and muscle-pull, across bony surfaces help in the maintenance of the bones’ health condition.

Muscle

Muscle synergies within our body is what allows us to move in our practice; such as maintaining an upright standing position by co-contracting the muscles around the ankle joint. Additionally, our muscles have peripheral sensory receptors that are sensitive to the change in muscle length (muscle spindles) and changes in tension resulting from stretching or contraction of a muscle (golgi tendon organs). This is the body's way of protecting the muscle from over-stretching or tearing. So, next time you’re in a seated forward fold, listen to your peripheral sensory receptors and ease into your pose taking deep breathes along the way!

Joints

When two bones come together, they form a joint. Joint surfaces are covered with a smooth cartilaginous tissue and contain synovial fluid in order to reduce friction and allow for ease of motion. Each and every joint in our body has degrees of freedom (or range of motion). When we are new to a pose, we will likely have a constrained movement in order to make the pose easier, but as we transition to become more advanced, we release some degrees of freedom resulting in a more energy efficient and coordinated range of motion.

Tendons & ligaments

Tendons: connective tissues that join muscles to the bones.
Ligaments: connective tissues that join bone to the bone.

Pranayama

Prāṇāyāma is the formal practice of controlling the breath in yoga and in meditation. Breath is fundamental to our everyday lives; an automatic process that, for the most part, we take for granted. The anatomical structures that facilitate the breath include the lungs, diaphragm, and intercostal muscles. Thus, when you inhale, your diaphragm contracts and presses downward, creating more space in your chest cavity for the lungs to expand. Additionally, the intercostal muscles (muscles between ribs) raise the ribs and also help expand the chest cavity. Similarly, when you exhale, your diaphragm and intercostal muscles relax and the space in the chest cavity reduces. Without getting too much into the physiology of pranayama, the lungs contain tiny balloon shaped structures that allow for the passage of oxygen and carbon dioxide in a process called gas exchange.

Dhyana

Building upon asana and pranayama, dhyāna involves concentration, meditation, and quieting of the mind. Although there are many different forms of meditation; one central theme is stillness — experienced in both the mind and body. In dhyana, we focus the mind on bringing forth of a conscious intention and practice becoming absorbed in it without drifting into concerns about the past or future. Researchers from Harvard Medical School found that mindfulness meditation can actually change the structure of the brain! Their findings suggested that after an eight week Mindfulness-Based Stress Reduction (MBSR) program, participants had increase cortical thickness in the hippocampus (governs learning and memory), posterior cingulate cortex (emotion formation and processing), the temporo-parietal junction (comprehension of our body’s position in space), and the cerebellum (regulates motor movements). Their findings suggest that meditation not only changes the brain, but it changes our perceptions, mood, level of arousal, and overall psychological well-being.

Below, I have listed some other great meditation studies that have come out in the last couple of years.

• Forever Young(er): potential age-defying effects of long-term meditation on gray matter atrophy

• Meditation Programs for Psychological Stress and Well-being

• Meditation experience is associated with differences in default mode network activity and connectivity

• Change in Brainstem Gray Matter Concentration Following a Mindfulness-Based Intervention is Correlated with Improvement in Psychological Well-Being

• Neural correlates of mindfulness meditation-related anxiety relief

Thanks for reading!

Cass

Reference:

Hölzel, B. K., Carmody, J., Vangel, M., Congleton, C., Yerramsetti, S. M., Gard, T., & Lazar, S. W. (2011). Mindfulness practice leads to increases in regional brain gray matter density. Psychiatry research, 191(1), 36–43.