Breathe Yourself to Sleep
Janet Wilson, who has taught yoga for more than 25 years, recommends this breathing technique for people who have sleep problems. It combines two important elements of relaxation: deep breathing and mental focus.
1. Lie on your back in bed. Take 4 diaphragmatic breaths (long, slow, and deep) through your nose.
2. Turn onto your left side, and take 8 diaphragmatic breaths.
3. Return to your back, and take 16 breaths.
4. Then (if you are still awake), turn onto your right side, and take 32 breaths.
5. Continue to turn in this sequence, doubling the number of breaths with each turn.
Janet assures me that people usually fall asleep long before they have exhausted their mathematical skills.
from How to Sleep Soundly Tonight: 250 Simple and Natural Ways to Prevent Sleeplessness by Barbara L. Heller