The Merriam-Webster dictionary defines inversion as a change in the position, order, or relationship of things so that they are opposite of what they had been.
Practicing inverted poses "Viparita Sthiti" positively impacts the body's four primary systems: cardiovascular, lymphatic, nervous, and endocrine. This action of reversing gravity improves overall health shifting the orientation to the head, which affects our mental, emotional and spiritual psyche, reducing anxiety and stress while increasing self-confidence and concentration.
The circulatory system is comprised of the heart and lungs, which feeds the body oxygen, and removes waste products from the cells. Arteries pump freshly oxygenated blood from the lungs outward. The veins return blood to the heart using a low-pressure system called the venous return system, which uses muscular movement or gravity to move the blood along.
One-way valves prevent backwash and keep the fluids moving towards the heart.
The heart also gets a break when going upside down because when upright, it is consistently working to ensure that freshly oxygenated blood makes its way up to the brain. When inverted, this pressure is reversed, allowing blood to move to the brain with minimal effort.
The lungs also benefit from being upside down because gravity naturally pulls the body's fluids downwards when we are upright. The lower lungs are more saturated with blood, thus going upside down ensures more blood flow to the upper region of the lungs bringing more oxygen-to-blood exchange.
The lymphatic system is the body's drainage system and protects the body from germs, viruses, bacteria, and fungi. This system is a network of vessels known as lymph nodes that filter unused proteins, waste materials, and excess fluids from the body dumping the remains back into the circulatory system where they are removed from the body.
This system works the same way as blood returning to your heart via the venous return system. Because the lymphatic system is a closed pressure system, it has one-way valves that keep lymph moving towards the heart. When one goes upside down, the entire lymphatic system is stimulated, thus strengthening your immune system.
There are several endocrine organs or ductless glands in the human body that, when bathed in blood, absorb the blood's nutrients and secrete hormones for a balanced and well-developed body and brain. If the glands fail to function properly, hormones are not produced as they should be, and the body starts to deteriorate.
Headstand and shoulder stand are referred to as the king and queen of all yoga asanas. They have opposite energetics, and it is important to practice them daily for overall health.
Headstand "Sirsasana" stimulates the pituitary and pineal glands while bringing blood flow to the brain cells. These glands are responsible for growth, sex hormones, and the overall chemical balance of the body. Practicing headstand develops more of the masculine qualities of willpower, sharpness of the brain, clarity of the mind, and stimulates the nervous system. Additionally, balancing creates centeredness and presence, which is calming and soothing. Headstand increases the gastric fire "Agni" and produces heat in the body, which improves sleep patterns, memory, and vitality.
Shoulder Stand "Sarvangasana" positively affects the thyroid, parathyroid glands, and lymph glands located in the neck region. While doing shoulder stand, there is a firm chin lock, which increases blood supply to these glands that secrete hormones for the body and brain's proper functioning. Doing shoulder stand cools and neutralizes the body, sedating the nervous system and develops more feminine qualities of patience and emotional stability.
The gravitational pull of going upside down also affects the abdominal organs relieving constipation, urinary and uterine disorders.
Please note it is best to consult with a qualified yoga instructor before you started practicing these poses, especially if you suffer from high blood pressure, eye disorders, cardiovascular diseases, kidney ailments, and spinal, neck or shoulder concerns.
During menstruation, women are advised to avoid inversions. At this time, the energy of the body in a woman's cycle is moving downward, and going upside down during the menses disturbs this natural rhythm. It can result in a feeling of shakiness, disorientation, or nausea.
Time spent upside-down every day, especially in Sarvangasana and Sirsasana, is one of the best things you could possibly do for yourself. These two poses create an essential balance physically, mentally, emotionally, and spiritually, bringing health and vitality to the body while calming and soothing the body, mind, and spirit.