Increase your vital energy through Pranayama which means controlling (Yama) the vital energy (Praná) through yogic techniques. This control happens through the change of the dimension of breath to a healthier one through the breathing techniques which we call Pranayama. Thus Pranayama increases the life force in you enhancing the vitality and energizing the body and mind by strengthening the nervous system.
The technique is totally scientific and can be medically explained. Flow of more oxygen through breath or the techniques of changing the dimension of breath supplies more oxygen to lungs and more oxygenated blood to the brain and all parts of the body. This in turn energizes the central nervous system (CNS) increasing the bio-energy in the body and putting the body more in rhythm with its natural bio-rhythm. This itself energizes the immune system and frees you of the diseases and ailments or even future diseases too. It takes care of the subtle energies and the aura and prevents any negative influence to enter even at the subtle levels too. Thus it prepares you for a body free of diseases, mind free of inhibitions and a soul free of grief and sorrow.