When to Use Ice vs. Heat for Pain Relief

Ice vs. Heat: Which Therapy Should You Use for Pain Relief?

Whether to use ice or heat for pain depends on your injury type, stage of recovery, and symptoms. While ice is known to reduce inflammation, swelling, and bruising, heat is best known for increasing blood flow and relaxing muscles. A general rule of thumb—use ice for new injuries and heat for long‑term tightness or pain. But to better understand the differences, let’s dive further into the biomechanics of your body.

How Ice (Cold Therapy) Works

To better understand the positive effects of ice, it is important to understand how nerves work. Nerves use electric and chemical gradients to transfer information and signals to and from the spinal cord and brain. Information about any sensation you feel is collected by the nerves and sent to the brain to be organized and understood. The brain determines if the sensations you are experiencing are “painful.”

Ice and cold can reduce the speed at which the nerve transfers information and signals, which reduces the amount of information the brain has to organize. This reduces the overall amount of pain you will feel. These effects are not permanent, however. Depending on the extent of your pain, the remedy may not last long. Repeated icing may not help either, as there are diminishing returns after a certain point.

🧊 Use Ice for:

• Acute injuries (within 48–72 hours)

• Inflammation or swelling

• Bruising

• Sharp or sudden pain

• Post‑surgical swelling

Examples: Sprains, strains, joint inflammation (like from overuse), contusions

How it helps:

• Reduces blood flow

• Minimizes swelling and tissue damage

• Numbs the area for pain relief

How Heat (Heat Therapy) Works

While ice targets the nerves, heat targets the tissue around it. Muscles and tendons are known to get tight, and this results in discomfort in either a very pinpoint area or a broad area, depending on the size of the muscle or tendon. Tightness from muscles and tendons can result from joint stiffness, muscle weakness, or overuse. Soft tissue, like muscle and tendon, has a structural property that can be changed by heat. Sustained heat from a warm towel or electric heat pack can reduce the degree of tightness present in the muscle by allowing the tissue to become more malleable. Following up with light exercise will help maintain the effects of heat on the tendons.

Note: Existing inflammation and swelling can be made worse with the addition of heat, as more heat can contribute to the continuation of the inflammation cycle, so be cautious if you are actively managing swelling.

🔥 Use Heat for:

• Chronic pain or stiffness

• Muscle spasms

• Tight or sore muscles

• Joint stiffness (arthritis, old injuries)

• Before stretching or physical activity

How it helps:

• Increases blood flow

• Relaxes muscles

• Improves flexibility and range of motion

Ice vs. Heat: Quick Decision Guide

When deciding whether to use heat or ice, it can be valuable to attempt some light stretching where you are not causing high levels of pain.

Regardless of which you choose, remember that neither is a substitute for medical treatment or guidance from your primary care physician or physical therapist—both are intended only to modulate pain.

⚠️ Avoid Using Ice or Heat When:

• Applying heat on fresh injuries (can increase swelling)

• Applying ice right before intense activity (may reduce muscle flexibility)

• Treating open wounds or areas with poor circulation without medical advice

Need personalized guidance on managing pain or planning your rehabilitation? Schedule a free injury assessment with AzOPT and let our Doctors of Physical Therapy help you choose the right treatment approach.

References

1. Law L, Rayi A, Hendrix JM, Derian A. Cryoanalgesia. StatPearls [Internet]. 2024 Feb 14–. PMID: 29489178.

2. Malanga GA, Yan N, Stark J. Mechanisms and efficacy of heat and cold therapies for musculoskeletal injury. Postgrad Med. 2015 Jan;127(1):57‑65. doi: 10.1080/00325481.2015.992719. PMID: 25526231.