This posture stimulates the thyroid and parathyroid glands, increases blood supply to the brain and also strengthens the upper body, opens the chest and stretches the neck, shoulders and uppper back muscles.
lie on your back and bend your legs and gently bring your thighs as much toward your chest as possible. Use your hands to help you move your hips up off the mat. Place the palms of the hands on the back of the ribs, resting the shoulders well on the floor. Tip your hips backward and bring your legs up to a 45 degree angle. Push from your toes, tip your hips backward into a more pronounced dog-tilt and allow your feet to leave the floor, bringing them until they point upward. Move your spine into your back, open and expand the chest and make your back slightly concave.
If you find it too difficult to raise your buttocks off the floor, then lie sideways by a wall with enough space between you and the wall for your buttocks and then swivel your body round to face the wall and climb your bent legs up the wall. Support your back as above (in bold) and stay here for as long as is comfortable.