Key facts
- Modality: Heat therapy (thermotherapy)
- Primary effects: circulation support, muscle relaxation, stiffness reduction, pain modulation
- Common contexts: stiffness, muscle guarding, longer-lasting discomfort patterns
- Common forms: heating pads/wraps, warm compresses, warm water exposure, sauna-style heat
- Poor fit: active swelling early after injury, impaired sensation, heat intolerance
- Decision support: Heat vs Cold Therapy
How heat therapy works
Circulation
Warming tissues is associated with vasodilation and increased local blood flow, delivering more oxygen and nutrients to the area.
Pain modulation
Heat stimulates sensory receptors that can reduce pain signal transmission and change pain perception.
Muscle relaxation
Warmth can reduce guarding and support tissue elasticity, which can help movement feel easier.
System effects
Whole-body heat exposure is associated with cardiovascular and autonomic responses that vary by individual health status and exposure type.
Cellular maintenance
Repeated heat exposure can activate heat shock proteins involved in cellular protection and stress adaptation.
When heat therapy is commonly chosen
Heat therapy is commonly chosen for stiffness, muscle guarding, and longer-lasting discomfort patterns. It is often used to support comfort and movement as part of a broader rehabilitation or self-care plan.
Common forms of heat therapy
Localized heat
Heating pads, warm compresses, wraps, and similar options used on a targeted area. These are common for back, neck, and joint stiffness contexts.
Warm water exposure
Warm baths, warm showers, and therapeutic pools used for broader warmth and relaxation. Individual responses vary with water temperature and exposure time.
Sauna-style whole-body heat
Traditional saunas heat the surrounding air. Infrared saunas use infrared emitters that warm the body more directly. Both are used for whole-body heat exposure and have different "heat feel" characteristics.
For implementation details and configurations, see Contrast Therapy Setups.
When heat therapy is a poor fit
Heat therapy is commonly avoided early after injury when swelling is prominent, and in situations where sensation is impaired or heat exposure creates excessive discomfort.
Risks and safety considerations
Heat exposure can cause burns and can place additional demand on the cardiovascular system (especially in whole-body heat settings). Use a barrier for localized heat, monitor skin response, and stop if pain, burning, dizziness, nausea, or unusual skin changes occur.
How heat therapy fits in the system
Heat therapy is one of the two foundational thermal modalities. It is commonly paired conceptually with cold therapy because the two modalities are chosen based on timing and symptom profile.
For decision support, see Heat vs Cold Therapy. For the alternating approach, see Contrast Therapy.
Where to go next
- Cold Therapy
Learn about cold therapy mechanisms in depth.
- Heat vs Cold Therapy
Choose the modality based on timing, symptoms, and goals.
- Contrast Therapy
Understand the alternating approach and its safety considerations.
Sources & review
Reviewed: 2026-01-21. Reviewed for clarity and citation coverage.
- [1] AAPM&R PM&R KnowledgeNow. Therapeutic Modalities – Thermal. now.aapmr.org
- [2] Cleveland Clinic (2025). Ice vs. Heat: What Is Best for Your Pain? health.clevelandclinic.org
- [3] Cleveland Clinic (2024). Heat or Ice for Arthritis Pain? health.clevelandclinic.org