Question: If I meditate too little I don't have energy throughout the day and if I meditate too long, I can't maintain my aspiration. How can I stabilise my energy level?Sri Chinmoy: The problem is that you are going to extremes. Sometimes you overeat and then you can't digest what you have eaten; sometimes you don't eat at all and you feel weak. When you don't meditate you feel miserable, and when you meditate beyond your capacity you feel worn out. But you don't have to pull, you don't have to push. You only have to know how much capacity you have. In your case twenty minutes in the morning and in the evening is more than enough. If you meditate for only two minutes or five minutes, naturally you will not be inspired: but if you meditate for an hour or two you will strain your capacity. So meditate devotedly and soulfully for twenty minutes in the morning and twenty minutes in the evening, and in the afternoon if you have a chance you can meditate for two or three minutes more. That will be ample in your particular case.
Sri Chinmoy, Meditation: God's Blessing-Assurance, Agni Press, 1974