Premanand Maharaj Ji
What can I do when I feel sleepy and lazy during bhajan?
Give sleep its six hours, then fight it
Give the body its six hours of sleep at night, and keep to sattvic food. After that, fight sleep and laziness during bhajan by standing, walking or holding cold water in the mouth.
If sleep comes, you should stand and do bhajan. Start walking. Keep cold water in the mouth like this.