It is an unfortunate fact that in day-to-day living man does not realize the extraordinary importance of relaxation. The very word brings images of some kind of discipline like yoga or something similar to be done at a particular time of the day. As a matter of fact, relaxation can be of three kinds: physical, mental and transcendental - and none of these would necessarily demand a system as such.
Thus, physical relaxation simply means deliberately, consciously releasing the tension that has somehow crept into the body. For instance, merely sitting in the dentist's chair causes tension. The dentist, therefore, has to tell the patient to relax. All that is really necessary in such a case is to make oneself consciously relax all the muscles in the body at one time. This is really the basis of the famous shavasana: you lie down and let all the muscles consciously let go of all tension. You are sometimes told to go gradually from one end of the body to the other, relaxing muscles in each part of the body. But it has been the experience of many that one clear command to the muscles in the entire body consciously to let go works very well. "Slack off" was what one dentist had to yell at his patient before the patient did relax.
The real benefit of physical relaxation is found not in doing the shavasana which needs you lying down, but at any time, whatever you are doing, to stop for an instant and consciously relax the whole body and then while you are so relaxed, to continue whatever you were doing. Or, you could take a minute or two between your tasks, and stay consciously relaxed. You will soon find that you get into the practice of doing your normal work without getting into any kind of tension, and only a gentle reminder to relax is all that is necessary.
There is an in-built mechanism for relaxation unique to the human being: the human being is the only animal who laughs and can laugh heartily. Laughter, even deliberately induced laughter, not only provides emotional satisfaction, but also significant physiological benefits and relaxation. The basis of laughter is a deep inhalation followed by rhythmic exhalation, especially using the diaphragm, the large muscle mass in the body that separates the abdominal and chest cavities. This helps equalize the pressures in both the cavities and apart from aiding venous drainage, also causes massage to the internal organs.
There are four types of laughter described by health practitioners that can be beneficial (people with heart or lung problems or high blood pressure should use caution):
a) 'Etiquette laughter' starts with a smile and extends to mild laughter, with no special attention to breathing. The tempo gradually builds up.
b) In 'pigeon laughter', a deeper inhalation is done and, keeping the mouth shut, you produce laughter making the sounds like hums of pigeons. This is an internal laughter and has its own advantages.
c) 'Soundless laughter' is the most difficult to learn, but very effective. Take a very deep in-breath, and then open the mouth and put the tongue out and let laughter out - but without making any sound! Also, after one inhalation you can exhale as long as possible, with rhythmic jerks to the diaphragm; this 'inner jogging' is vigorous and exhausting.
d) 'Belly laughter' is similar to the soundless laughter, but you let go and laugh loudly - even rolling on the floor or doubling up. Repeated in-breaths are needed and this can last for as long as you like.
Excerpted from Peace & Harmony in Daily Living by Ramesh Balsekar