Now relax and breathe normally. American psychologist Dr Kathleen Dillon found that popping bubble wrap reduces stress levels by releasing muscular tension. Just say no. If it seems like an impossible task, start small. Practice being assertive with people you don't know - in queues, on the bus, in shops.
Floatation tanks are a proven stress-buster.
You can gain a little of the benefit in your own bath. Spend at least half an hour soaking. Choose the music you listen to with care. Tests have shown that half an hour of harmonious classical music can be as effective as a dose of Valium in intensive care units. Tibetan chanting may be even more powerful.