Soaking in a hot tub or spa can be therapeutic and relaxing, but there are a number of health concerns associated with hot tub use.
If you have been diagnosed with heart disease or high blood pressure and are being treated medically, the increased heat from a hot tub can have an undesired interaction with medication. Speak with your doctor prior to use.
Pregnant women should not use a hot tub due to the health risks associated with a mother's increased core body temperature when pregnant. Increased heat can injure a fetus.
Extended exposure to heated temperatures—such as those found in most hot tubs—can result in lowered sperm production.
Extended Periods of Soaking
In general, one should spend no longer than 20 minutes in a hot tub at a time. Staying longer can result in dehydration and elevated body temperature, which can result in more serious health issues.
Using a hot tub that has not been properly maintained and chlorinated can result in the contraction of any of a number of unpleasant illnesses, from a treatable itchy rash to genital herpes. Make sure a hot tub has been maintained before using.