For many, meditation's greatest challenge is not to feel sleepy in the act. Of course, it is wonderful that meditation can bring about such a relaxed state, however, it is ultimately counter-productive. There are many things you can try when you catch yourself nodding off in meditation (or to prevent nodding off altogether).
First, ensure that your posture is upright. Sit on the floor with a pillow under you (causing your hips to tilt slightly forward) for help. Still others recommend sitting directly on the hard ground in the lotus position if sleepiness is an issue. Furthermore, many people do sit up straight while meditating, but they do it with the aid of leaning on a chair back or wall. While this might seem like good posture, the very best stance for proper meditation is to support your own weight. If sitting up straight doesn’t do the trick, standing is also an option.
Another tip is to simply be mindful of the sleepy feeling. When a drowsy sensation arises, simply take note of it without concern or sentiment. As you know with other intrusive thoughts and feelings during meditation, the practice of mindfulness allows one to acknowledge the disruption without losing focus or getting distracted from the meditation. Let the sensation of sleepiness fade away as you would any other unwanted thought during meditation.
If sleepiness is a chronic problem, consider changing the time of your daily meditations. Maybe a before-bed or after-waking meditation is not appropriate for you. Studies show that our minds are most active in the late afternoon—try meditating or 3:00 or 4:00 PM everyday. As counter-productive as that may sound, it will certainly teach mental discipline and flexibility. Also, meditating right before a meal (preferably lunch or dinner) is a recommended time.
Having a cup of green tea before your meditation is another option. Green tea is naturally caffeinated and known to invigorate and energize. Drinking too much tea might create the feeling of agitation or needing to use the restroom during the meditation (which can certainly help keep you awake but also be highly distracting). Take a few sips of green tea on an empty stomach for the best results.
You might also consider trying walking meditations or open-eye techniques so the meditation is less like sleep. In walking meditations, you simply walk around your neighborhood or a natural area (river, lake, hill, garden, forest) and practice mindfulness. You see what you see, noting it but not allowing a mental dialogue to flow in your mind. Likewise, open-eye techniques involve staring at a spot on a soft-colored wall or allowing your eyes to glaze over and become foggy so that you are seeing but not looking. In general, any non-rhythmic focus during the meditation can help keep you awake (such as focusing on listening rather than breathing).
Still other meditation gurus argue that sleepiness during meditation is not really a concern. They say as long as you come out of the meditation to find greater peace and serenity, your purpose has been accomplished. Whether this sentiment resonates with you or not is entirely up to you. If your purpose in meditation is to connect with God or the Universe (not relaxation), then sleepiness may still be an issue.
~ Jillian Avey, purelifemeditation.com