Yoga is an ancient art from india built upon hinduism. According to Sivananda, one of the saints that helped bringing it to the west, it consists of 5 points:
- Proper Excercise - Asanas
- Proper Breathing - Pranayama
- Proper Relaxation - Savasana
- Proper Diet - Vegetarian
- Positive Thinking and Meditation - Vedanta and Dhyana
Proper excercise is very healthy, it increases the strength and length of muscles, increases blood flow to all parts of the body and in general keeps the body young.
Proper breathing or the yogic breathing excercises have been a subject to some scientific studies. To my knowledge, none of those found any long or short term benefits of breathing excercises on the human body or any improvement on breathing related diseases like Asthma. Anyhow, some of them are able to increase the tidal volume (the volume of air inhaled and exhaled with a single breath).
Proper relaxation is indeed one of the most important and also forgotten things of our time. Too many people become sick because of constant stress.
Proper diet is also very important. Being a vegetarian is proven to be better for your health than eating meat every day.
Positive thinking and meditation can also be called psychosomatic. Whenever your mind thinks of something, it can always affect your body. Hence it is very important to keep those positive thoughts coming.