It’s an idyllic image: a group of friends celebrating one event or another, drinks in hand, sitting in a hot tub full of frothing water that bubbles from the hot tub jets. The night is young and everyone is smiling and having a great time.

While this image is just–an image–the hot tub has been seen often as a tool for get togethers, whether that is with friends or with families. Resorts will tout hot tubs as an opportunity to spend time with others, often in a partying sense.

Hot tubs, however, have other purposes aside from having fun. 22.4% of hot tub owners purchased their tub with the primary purpose of recovering from an injury, for instance, and recent studies in the New England Journal of Medicine showed that people with Type 2 diabetes had an easier time controlling plasma sugar levels and weight after soaking in a hot tub six days per week.

This is a guide on the health benefits of a hot tub. To start, here are some statistics about hot tubs generally in the United States:

• A well-constructed hot tub can last 20 years or more
• As of spring 2014, about 20 million Americans owned a pool, spa, or hot tub
• 42% of hot tub owners say they use their hot tub to bond with their family

Hot tubs have health benefits. Here are a few to think on.

Improving Sleep

33.3% of hot tub owners purchased their tub with the primary purpose of improving sleep. In fact, its a truism that taking a late night bath or shower can ease a person into sleep. Science has shown that when you’re feeling cold, your body’s rhythms are disrupted, meaning you’ll take longer to fall asleep and have more disruptions when you do.

Sleep is, in fact, central to our body’s functioning. REM sleep, which is the deepest period of sleep and when you dream, is associated with increased performance, a more stable mood, and overall better cognitive effectiveness. Times when you don’t get enough sleep lead to poor overall health, less productive work days, and worsened mood.

A hot tub, then, improves sleep quality, leading to more productivity during the day, a better mood, better functionality, and improved cognitive performance.

Reduced Stress and Anxiety

Scientists have shown that hot tubs reduce stress and anxiety. But it may surprise you to know how. Much of it, of course, has to do with the warm feeling of the water and the gentle soothing motion of the jets, but there is another factor that has to do with why hot tubs reduce stress and anxiety:

Weightlessness. A hot tub, much like a swimming pool but even more so because of the jets, which add force, leads to a feeling of ‘zero gravity’ where in essence you feel weightless. This is a pleasurable feeling and can lead to reduced stress and anxiety.

Reduced Joint Pain

Hot tubs can ease arthritic pain, which is pain caused with the small joints, generally in the hands, wrists, ankles, and feet. This is due to a few factors. First, the heat from the hot tub reduces inflammation, which is a factor in joint pain. Also, like the section above, the weightlessness of a hot tub eases pressure on joints.

This reduces stress on the joints and relieves pain. In effect, when in water, you actually weigh only 10% of your body weight, which relieves pressure not just on joints but on damaged bones or any other injury.

Hot tubs and spas have the general ability to reduce both mental and physical health symptoms, whether those symptoms are arising from stress and anxiety or from inflammation in the joints. Almost 45% of hot tub owners showed a preference for taking a dip in the hot tub late at night, this to help them sleep.

While most hot tub owners prefer a temperature between 100 degrees and 102 degrees, the temperature from hot tub to hot tub may vary. Hot tub owners may have their personal preferences, as will a gym spa temperature, and a resort spa temperature.

One particular brand of hot tub that has garnered recent acclaim are the Sundance hot tubs. They are made by a reliable manufacturer and get the job done fairly well.