I first saw this breathing meditation in a yoga book in 1969. This is a good meditation to do for several rounds when you need a short centering pause, or as a starting off point for a yoga routine, an exercise warmup, or a longer meditation. When I do this simple meditation, I calm down, I come back to my centre, and I feel better.

How to Practice

Blow your nose if it's stuffy and get that out of the way. Sit in a comfortable easy position.

Put your right hand up to your nose. Gently rest your index and middle fingers on your forehead just above your nose. Your thumb will be resting on the right side of your nose and your ring and baby fingers will be on the left side. If you're left-handed, or prefer to use the other hand, reverse this.

The idea here is to breathe from one side of the nose for one breath and the other side on the next, BUT you switch half-way between breaths. So you breathe out with your thumb pressing gently against the right nostril to keep it closed, and breathe in on the same side, then before you breathe out, switch sides, pressing your ring finger gently against the left nostril to close it, breathing out on the new side and in again on the new side. Switch back and breathe out pressing your thumb and in, then continue in the same way.

Some people suggest you need to count to four, some say to eight in each position, I say just breathe easily and quietly. The whole idea is to work with your breath where you are at the time and enjoy it. If you find the position of the index and middle fingers on the forehead a bit awkward, try curling them down towards your palm instead.

Continue for a few rounds.

To simplify:
    In through the left,
    switch sides,
    out through the right,
    in through the right,
    switch sides,
    out through the left,
    in through the left,
    switch sides,
    ... and so on

It might take you a couple of rounds to get the hang of it, but that's all it takes if you're paying attention.

At any given time through the day, we will find that we get more air through one nostril than another, and this shifts sides throughout the day. If we have one side that dominates too much, this meditation can help bring the cycle back into balance and bring our energy channels back into balance. It has also been shown that these airflows correspond to brain activity. More air through the left brings more activity in the right brain. And vice-versa. So it's no surprise that we feel more balanced afterwards.

Notes

If you are really stuffy or have a cold, you can still participate. Keep both nostrils open so that you can breathe comfortably, but go through the rounds as though you were closing and opening as directed. The attention you pay to the process can create a small but noticeable change in energy flow.