A study published in June 2025 by the American Physiological Society examined how hot baths, dry saunas, and infrared saunas affect the body. Researchers found that hot water provides more health benefits than the other two methods.
They tested this by checking how each method affects body temperature, heart function, blood flow, and the immune system. The hot bath clearly came out on top.
What the Study Found
- Hot baths raised body temperature more than saunas
- Heart rate and blood circulation improved more during hot baths
- The immune system reacted more strongly to hot water
- Heat therapy could help people who don’t or can’t exercise
Why Hot Water Has a Bigger Effect
Water transfers heat better than air. That means a hot bath warms your body more than a sauna can. In a sauna, your body cools off by sweating. But in water, your body keeps heating up.
As a result, your core temperature rises more in a hot bath. That stronger heat seems to trigger more health responses.
How It Helps the Heart
The heat from the bath made people’s hearts beat faster. Blood started flowing more freely, which can support heart health.
The researchers say this kind of heat exposure may:
- Improve circulation
- Lower blood pressure over time
- Keep blood vessels flexible
These effects are similar to what you get from light exercise.
Effects on the Immune System
The hot bath was the only method that activated the immune system. The study showed that immune cells and helpful chemicals in the blood changed after hot water exposure.
This may help the body stay alert and ready to fight off illness.
A Good Option If You Can’t Exercise
If you’re not able to exercise due to injury, age, or health problems, a hot bath could offer similar benefits.
It may help improve:
- Heart and blood vessel health
- Immune system activity
- Body temperature regulation
Still, people with certain health conditions should talk to a doctor before starting heat therapy.
Simple Tips for Safe Use
- Start with short sessions, about 15–20 minutes
- Drink water before and after
- Avoid using very hot water
- Take breaks if you feel dizzy or lightheaded
- Ask your doctor first if you have medical conditions
Final Thoughts
Hot baths may be more than just relaxing—they might improve your heart, blood flow, and immune health. This study shows that regular hot water immersion could be a simple way to support your well-being.
If you’ve ever wanted to boost your health while lying still, a hot soak might be your best option.
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Benjamin Spencer
Benjamin Spencer is the co-founder of Healthy Living Magazine. With a focus on health tech, fitness trends, and real-world longevity tools, he’s passionate about breaking down complex wellness ideas into practical, everyday habits that actually work.
