CLAIM: Sauna Session May Be As Good As Exercise For The Heart. “Relaxing in a hot sauna may not only feel good — it might affect your heart and blood vessels in ways that are similar to moderate exercise. That’s the finding of a new study that tested the effects of a 30-minute sauna session. The researchers say their results may help explain why people who regularly use saunas tend to have a decreased risk for heart disease and even dementia.”