The experts at N.I.H. say you may have to repeat this process a few times.Use water that is body temperature.If the water is cooler or warmer, it could make you feel dizzy.

• 的专家表示，这个过程可能需要重复数次，所使用的水的温度要与体温相同，如果水温有一点冷或一点热，都可能使你感觉头昏。