Heat and Cold Therapy in Physiotherapy: When and How to Use Each

What are heat and cold therapy?

Heat therapy (thermotherapy) is the application of warmth — via hot packs, heat wraps, or warm towels — to ease pain and stiffness. Cold therapy (cryotherapy) is the application of cold — via ice packs, gel packs, or cold wraps — to a painful or freshly injured area. Both are simple, non-invasive, and among the easiest modalities to use safely at home.

How they work

Heat widens blood vessels and increases blood flow to the area, which helps relax tight muscles, ease stiffness, and soothe aching joints.

Cold narrows blood vessels and reduces blood flow, which numbs the area to dull pain and helps limit swelling and inflammation after a fresh injury.

When to use heat versus cold

As a general rule, heat suits ongoing, chronic problems and cold suits fresh, acute ones — though a physiotherapist can advise for your situation.

• Heat: chronic stiffness, muscle spasm, ongoing aches (for example, osteoarthritis or long-standing back stiffness).
• Cold: acute injuries and swelling (for example, a fresh sprain or strain), and for short-term pain relief.

What the evidence says

Heat has the firmer evidence base. A Cochrane review found moderate evidence that heat-wrap therapy gives a small, short-term reduction in pain and disability in acute and sub-acute low back pain, with better results when combined with exercise. For cold, the same review found insufficient evidence to draw firm conclusions for low back pain.

The "ice everything" mindset has also softened. Reviews found only limited evidence that ice improves clinical outcomes in acute soft-tissue injury, and newer frameworks such as PEACE & LOVE (which replaced RICE) emphasise protection, gentle early movement, and progressive loading over prolonged icing. Cold can still help short-term pain, but it is no longer seen as essential to healing.

Using heat and cold at home

Both are highly portable and inexpensive — reusable hot packs and heat wraps, or ice packs, gel packs, or a bag of frozen peas wrapped in a cloth. This makes them ideal for home use under a physiotherapist’s guidance.

Typical guidance is to apply for about 15–20 minutes at a time, always with a cloth or towel between the pack and the skin, repeated every few hours as needed.

Safety and cautions

Heat and cold are low-risk when used sensibly, but a few precautions matter.

• Always place a towel or cloth between the pack and the skin — heat can burn and cold can cause ice burns.
• Keep to time limits (about 15–20 minutes) and never fall asleep on a heat pack.
• Take extra care, or seek advice, if you have reduced sensation, diabetes, poor circulation, or Raynaud’s.
• Do not apply to broken skin or open wounds, and avoid heat on a fresh, swollen injury.

Sources

• French SD, et al. Superficial heat or cold for low back pain. Cochrane
• Dubois B & Esculier JF. Soft-tissue injuries simply need PEACE and LOVE. Br J Sports Med, 2020
• Harvard Health — Cold versus heat for pain relief: how to use them safely and effectively

Other modalities

• TENS (transcutaneous electrical nerve stimulation)
• Therapeutic ultrasound
• Muscle stimulation (NMES / EMS)
• Interferential current therapy (IFC)
• Low-level laser / red-light therapy (LLLT)
• Resistance bands
• Weights & resistance training
• Pneumatic resistance training
• Cable functional trainer
• Motorised cycling therapy
• Supported treadmill gait training