We have already seen how our body responds in the 'fight or flight'mode. While relaxing, the exactly opposite physiological changes take place in the body.

As mentioned before, two branches of the autonomic nervous system is responsible for the changes. When the relaxation response sets in, the sympathetic branch slows down and the parasympathetic branch take over- the body and mind calm down, metabolic rate of the body slows down. Now our body requires only a very low maintaining energy, similar to the low metabolic rate seen in deep sleep.

Our breathing becomes more regular and the heart rate comes down to normal range. In the sustained state of relaxation, oxygen requirement of our body tissues falls down even lower than that during normal sleep. The blood lactate level also falls significantly, three times faster during meditative relaxation than normal restful state. (Lactate is the chemical that enters the blood through the metabolic activity of the skeletal muscles and is responsible for the muscular fatigue). Blood pressure is also brought down to pre-stress levels. It is easy to see that the relaxation response allows the body to recover from the strains of everyday stress.

The alteration in brain activities brought about by relaxation mode is still more interesting. Usually our brain emits four types of waves, each with its own rhythms:

1. Alpha waves: Prominent when the mind is active, but in a relaxed state.
2. Beta waves: This is seen during everyday conscious rhythms
3. Delta waves: Emitted during normal sleep
4. Theta waves: Emitted during a dream like state; subconscious mind active.