The practice of yoga helps reduce stress and increases productivity. Hence, you are comparatively less tired by the end of the day. This, in turn, leads to sound sleep and reduces the duration of sleep required.
The practice of pranayama (which means ‘breath control’; ‘prana’ means ‘life force’ and ‘ayama’ means ‘control’) potentially slows the heart rate, calms the mind, and relaxes the body. Bhramari, Nadi shuddhi and anuloma-viloma pranayama before going to bed have shown to greatly increase the quality of sleep