You haven't seen those signs telling you to limit time in the hottub/steam rooms in public places? It messes with your blood pressure and your heart has to work harder.

I did a quick search and found this:

"Why do hot tubs put your heart at risk?

When you submerge your body in hot water, your temperature rises, but your blood pressure drops.

Evaporating sweat normally helps cool you off. But, when you immerse yourself in hot water, that natural cooling mechanism doesn’t work. As a result, you can’t cool off.

When your body gets superheated:

Your blood vessels dilate to try to help cool off the body.Blood diverts to the skin, away from the body core.Heart rate and pulse increase to counteract a drop in blood pressure.

Normally, these events don’t cause problems. However, if you have existing cardiovascular disease, the cascade of events could overtax your heart. This can lead to:

Loss of adequate blood pressure, if your heart can’t pump enough blood. Increased blood pressure, if you have blood vessel disease or narrowing and hardening of the arteries. Dizziness or feelings of faintness. Nausea. Abnormal heart rhythms. Inadequate blood flow to the heart or body. Heart attack. Medications prescribed for heart conditions can also contribute to the problem:

Beta-blockers lower heart rate and limit cutaneous (skin) blood flow. Diuretics increase excretion of water and salt. A cardiologist’s advice Dr. Rimmerman describes the process this way: “A sudden rise in body temperature creates significant stress on your cardiovascular system, predominantly via a cascade of adjustments resulting in an elevated heart rate. The higher heart rate ― especially in the presence of reduced heart function, heart arrhythmias and coronary artery blockages ― can cause a cardiac event such as blood flow problems and, in the worst case scenario, manifest as a heart attack.”

https://health.clevelandclinic.org/hot-tubs-can-land-your-heart-in-hot-water/