A 30-minute warm bath may lower blood pressure more effectively than moderate exercise such as cycling, according to a new study.
Study details
The research assessed the impact of hot water and moderate exercise on 25 overweight and obese adults aged between 45 and 70. Participants were physically inactive, had resting blood pressure no higher than 140/90 mmHg, and a resting heart rate under 100 beats per minute.
Each participant underwent two sessions separated by at least 72 hours. In one session, they were immersed in 40C water for 30 minutes; in the other, they cycled on a stationary bike for half an hour.
Findings
Researchers monitored blood pressure, heart rate, and body temperature. They found that a warm bath caused a greater drop in blood pressure than moderate cycling over the 30-minute period.
The study also showed that hot water immersion can make blood vessels wider, creating more space for blood to flow.
Expert caution
Researchers stressed that baths cannot replace exercise, but they offer an alternative for people who struggle with conventional exercise. The study, published in the European Journal of Applied Physiology, said: "These data support further investigation of hot water immersion as a practical intervention, particularly for individuals with limited capacity for conventional exercise."
Dr. Adolph Hutter, professor of medicine at Harvard Medical School, previously said: "The high temperatures in a warm tub or sauna cause your blood vessels to dilate, which lowers blood pressure."
However, he warned that "people in their 70s and older whose blood pressure is on the low side also should be extra careful." If the water is too hot, blood pressure may dip too low, causing dizziness or lightheadedness.
He explained: "A water temperature of 100F (37.7C) to 105F (40.5) is reasonable. Get in slowly, so your body can accommodate gradually."
