Hot tubs combine heat therapy and hydrotherapy. Many people may find these forms of therapy as an effective way to help alleviate arthritis pain and loosen stiff joints.

A hot tub is a large tub of heated water that may also feature powerful jets to provide a massaging effect on the body. Some people use hot tubs for relaxation purposes, while others use them to improve health and well-being.

This article explains how heat can help alleviate arthritis pain and describes some of the potential benefits of using a hot tub for arthritis. It also outlines some important risks and considerations when using a hot tub and lists some alternative forms of heat therapy.

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Heat therapy may help reduce arthritis pain and stiffness. Applying heat to the joints causes the blood vessels in and around the joints to dilate or widen, increasing the delivery of blood, oxygen, and nutrients to the area. This can help with:

  • decreasing pain
  • relaxing the muscles and other tissues surrounding the joints
  • improving range of motion in the joints

An older study from 2010 involving 46 participants with knee osteoarthritis (KO) investigated the effect of local heat application on arthritis symptoms. One group of participants received a 20-minute application of heat every other day for 4 weeks in addition to their usual medication. The control group received only their usual medication.

The researchers found that the heat application statistically decreased KO pain and disability. It also led to improvements in the following:

  • physical function
  • general health perception
  • quality of life

A hot tub is an excellent way to combine heat therapy and hydrotherapy for arthritis pain. Potential benefits of hydrotherapy include:

  • increased blood flow
  • relief from pain and stiffness
  • muscle relaxation
  • increased range of motion in the joints
  • improved sleep quality
  • reduced stress and anxiety levels
  • enhanced well-being and quality of life

A hot tub or another form of warm water therapy may be beneficial for various types of arthritis, including rheumatoid arthritis (RA) and psoriatic arthritis (PsA).

Rheumatoid arthritis

A 2018 study compared standard care for RA with standard care plus spa therapy. The spa therapy intervention included 20-minute daily sessions in a thermal water pool.

The study implemented a crossover design, in which each participant took part in both arms of the experiment at different times.

The results showed that standard care plus spa therapy was associated with significant improvements in joint swelling compared with standard care alone.

Psoriatic arthritis

PsA is a form of arthritis that affects some people with the inflammatory skin-related condition psoriasis.

Some people with PsA may find that warm water stimulates blood flow and improves their arthritis symptoms. However, others may find that warm water triggers or exacerbates their psoriasis, increasing skin dryness and irritation.

A person with PsA should consult a doctor before deciding to use a hot tub to help treat their condition.

A person who uses a hot tub may have an increased risk of swimming-related illnesses. These typically occur as a result of infection with one of the following pathogens:

Individuals can get an infection if they swallow or come into contact with contaminated water, or if they inhale steam from contaminated water.

Swimming-related illnesses can cause infections in various parts of the body, including the skin, eyes, and ears. They can also affect the respiratory and gastrointestinal systems.

Possible symptoms of swimming-related illnesses include:

Certain people have an increased risk of becoming ill, including:

  • Children: Hot tubs are not suitable for children under 5 years of age.
  • People who are pregnant: A person who is pregnant should seek medical advice before using a hot tub, especially if they are in the first trimester of pregnancy.
  • People with certain health conditions: Anyone with the following health conditions should avoid using hot tubs:
    • impaired sensation, known as neuropathy
    • impaired ability to communicate
    • a cognitive impairment, such as dementia

Various types of heat therapy may help ease arthritis symptoms, including:

  • Taking a warm shower: The gentle massaging effect of a warm shower can help loosen stiff joints.
  • Bathing in warm water: Soaking in a tub full of warm water for about 15–20 minutes helps relax the weight-bearing joints.
  • Stretching after heat therapy: A person can perform gentle stretching exercises after a warm bath or shower to help increase joint mobility.
  • Applying heat packs: A person can purchase moistened heat pads or wraps from their local pharmacy. Alternatively, they can make their own heat pack by placing a damp, folded towel in the microwave for 20–60 seconds. Before applying the towel to the affected joint, a person should check that it is not too hot. If necessary, a person can wrap the towel in a thin, dry cloth before holding it against the affected joint.
  • Trying a paraffin bath: This method may be suitable for arthritis of the hands or feet. It involves coating the affected hand or foot in paraffin wax and wrapping a towel around the body part to help retain the heat. Generally, a person needs to wait for 20 minutes before peeling off the solidified wax.
  • Trying mineral oil and heat: A person with arthritis of the hands can try applying mineral oil to their hands, covering the hands with rubber gloves, and holding them under hot running water for 5–10 minutes.
  • Therapeutic ultrasound: This method involves applying high frequency sound waves to the affected joints to create heat deep inside the joint.
  • Diathermy: This therapy uses an oscillating high frequency electromagnetic field to heat the affected tissues.

Hot tubs are a form of heat therapy. Many people find heat therapy an effective way to ease arthritis pain and stiffness.

Besides hot tubs, people may find other forms of heat therapy beneficial, including bathing or showering in warm water, applying heat packs, or using paraffin baths.

Although most people can safely use hot tubs, they are not suitable for children under 5 years of age or people with certain underlying health conditions. A person who is pregnant should consult a doctor before using a hot tub. People should also be aware that using a hot tub can increase their risk of swimming-related infections.