A whirlpool bath works by recirculating the water already in the bath. The whirlpool pump once activated draws water into the chamber compresses it and forces it back through the jets with an infusion of air to create the massaging effect. A soak in a hot tub could be just the thing to relax you after a long day. The warm, bubbly water also eases aches and pains from conditions like arthritis, low back pain, and fibromyalgia. But hot tubs might not be safe for some people, including pregnant women and those with heart disease.