The most basic and fantastic answer to why people do yoga?

The most physical reason which can be seen directly and very quickly –

Your muscles will get stronger – the main benefit why people practice yoga asana is, it gives strength to your muscles. It is the main benefit of one of the eight limbs of ashtanga yoga which is – asana. When you practice some yoga asana/yoga poses and try to hold for a few seconds in the posture, that is the main point when your muscles get stronger. After holding in a posture, your yoga expert will make your practice the counter pose of that pose. That counterpose will make your muscle relax and also gives your strength from inside.

The reason which as a whole gives inner peace if you practice pranayama and meditation.
Why did I say inner peace? Even after 10 minutes of pranayama practice, specially bhramari pranayama, one can feel the peace. You will feel that your mind is relaxed, your breathing is longer than normal. You are very satisfied and calm. That state of your mind can be gotten by just some time of pranayama practice. And think if you are able to do this for a long time. Yes, magic will happen to you.

A complete health
Collectively it will improve your immune system. If you practice yoga asana in the morning and pranayama followed by yoga asana practice and after pranayama, you are practicing meditation, this will give you a fourfold development to your health. Like - mental health, physical health, social health, and spiritual health.

Regular practice reduces the risk and intensity of chronic diseases like diabetes and other hormonal diseases.
If yoga cannot cure your chronic diseases, like any chronic pain, diabetes and spinal injury or any malignant issue can be reduced to a very minimal level and in a long period of time, we can cure this. Yoga practices will also give your body strength to fight with any kind of disease.

Yoga asana practice gives your body flexibility and gives your body a toned shape.
As you practice different yoga pose, it gives impact in the form of stretch and contraction on different parts of your body. In this way, if your practice regularly, you will start getting your body in proper shape. And obviously, when you flex your muscles during your yoga practices, you will get a flexible body and relaxed muscles. This way you can improve the life of your organs.

Improves your sleep, reduces stress and anxiety if practices meditation daily.
Physical activity improves the blood flow in the body and breathing practices improves the flow of oxygen to the brain and other body organs. Some special pranayama vibrates the brain and gives a relaxed mind. In the result, you live a stress-free life, you can reduce your anxiety level. This is how yogic practices effect on your brain and the human body. This is why one should spend at least 40 minutes of morning in yogic practices.

Author's Bio: 

This article is just an overview to give you more motivation about yoga practices. Because after I finished my yoga teacher training in Rishikesh from one of the best yoga school in Rishikesh, I realized that yoga practices have the potential to make everyone happy and healthy without any side effect. Please follow this link if you also want to learn yoga from a very authentic source - yoga therapy training India