The autumn season is associated with the lungs and large intestines. This is a good time to work at keeping these organs strong and healthy. According to yoga teachings, yoga twists improve the functioning of the digestive system. When performing a yoga twist, the abdominal organs are compressed and squeezed, helping to release impurities from the cells. When you release the twist, the organs are soaked with a rush of fresh blood, bringing oxygen and nutrients to the cells.

Yoga twists also help you open the chest, shoulders, and back, which increases the capacity of the lungs to receive fresh oxygen and expel carbon dioxide. Each twist has its own unique list of health benefits. Ardha Matseyndrasana is specifically designed to increase the capacity of your lungs and tone the abdominal organs.

Instructions for modified Ardha Matsyendrasana
Sit on the corner of a firm folded blanket with the legs extended forward. Bend the knees and place the soles of the feet on the floor. Take your left foot under your right knee and around to the outside of your right hip. Your left knee should point straight forward and the toes of the foot straight back.

Take the right leg over the left and place the sole of the right foot on the floor to the outside of your left knee. The right ankle should firmly touch the outer left knee. Your right knee should face straight up and both knees should align with the center of your torso.

Your buttock bones should contact the blanket equally. If the right buttock bone is lighter on the blanket than the left, for example, increase the height of the blankets under both buttock bones until you can balance the weight between them.
Place the fingertips alongside the hips facing forward.
Press the fingertips down, inhale and extend the trunk up.
Keep the buttock bones stable, exhale and place the right hand behind your right hip. Hold your right knee with your left hand.
To deepen the twist, place your left upper arm to the outside of the right leg close to the knee.

Position the forearm perpendicular to the floor with the fingers of the hand pointing straight up.
Press the bent arm against the knee, exhale and turn the left waist and chest toward the right leg.
Be sure to keep the spine in the center of the posture as you turn.
Release, reverse the position of the legs and feet, and repeat turning to the left.