A group of 3,000 Dutch study participants voluntary concluded their daily showers with 30-, 60- or 90-second blasts of chilly water for 30 consecutive days. Researcher Geert A. Buijze compared their reactions and lifestyles throughout the experiment to a control group. He found that participants who took a cold shower for any of the three durations above took 29 percent fewer sick days off from work during the 30-day period.