Cold and heat have long been used to help with the rehabilitation of orthopedic injuries. Both recovery methods are convenient, affordable, and simple remedies for at-home use. However, misuse of heat and cold therapies can hamper recovery and even cause damage. In this month’s Recovery Round-Up, our physical therapists compare cold and heat therapies, outline benefits and drawbacks of each therapy method and provide guidance on how and when to apply them.
Mechanism and Benefits
Cold therapy is the application of any device or medium to the body that removes heat and decreases the temperature of body tissue. The reduction of temperature in the muscle activates the sympathetic vasoconstrictive reflex (i.e., a reduction in blood flow to the cold tissues) to reduce edema (i.e., swelling) and inflammation. Cold therapy is used to reduce swelling and inflammation following acute injuries.1 Reducing swelling and inflammation is important to maintain range of motion in our joints and to decrease pressure that causes pain.2 In addition, cold therapy acts as a local anesthetic, slowing the speed at which our pain-signaling nerves communicate and resulting in less pain and fewer muscle spasms.
Although cold therapy is effective at reducing swelling and inflammation, this does not necessarily accelerate recovery. Research shows that the inflammation following an injury is actually helpful in healing damaged tissue.2 Another argument against cold therapy is that it decreases flexibility and pliability of muscles and tendons, making this method contraindicated if used before activity. Lastly, if used inappropriately, cold therapy can put you at risk for tissue damage (e.g., frostbite). Follow the guidelines below for safe use of ice and other cold therapy methods.
When and How to Use
We recommend using cold therapies for no longer than one week following an acute orthopedic injury to maximize its positive benefits and to minimize any potential downsides. The most common modalities for administering cold therapy include ice packs, ice massage, ice baths, Game Ready® machines, and cryotherapy chambers.
Ice packs are most effective when used within 72 hours of an acute injury.2 Always avoid direct contact with your skin when applying ice packs to an injured body part by using a towel or cloth in between skin and ice packs to avoid ice burn. Ice packs should be applied for 15-20 minutes at a time with at least one hour in between icing sessions. Be alert to signs of skin irritation such as redness, rash, and raised areas.
Ice Baths and Cryotherapy Chambers
Full-body submersion in ice baths (tubs of cold water at temperatures between 45° to 55°F) and cryotherapy chambers (rooms or chambers using liquid nitrogen to cool ambient temperature to -220°) are popular in the active and athletic communities for post-exercise recovery. Individuals use ice baths and cryotherapy chambers within the first few hours following activity to decrease delayed onset muscle soreness (DOMS). A couple of recent studies show that frequent exposure in a cryotherapy chamber may compromise muscle growth and adaptation for the average individual.3,4 Ice baths and cryotherapy chambers are beneficial for athletes that need rapid recovery between strenuous activity sessions but could hinder the recovery process if chronically used for routine training.
Mechanism and Benefits
Heat therapy is the application of heat to the body resulting in increased temperature of body tissue. Heat therapy, in contrast to ice therapy, increases blood flow dilating blood vessels. This therapy decreases pain by relaxing the muscles and providing oxygen to ischemic (i.e., oxygen-deprived) tissues1. Heat also activates temperature-sensing nerve endings that block pain signals.5 Heat is beneficial for improving flexibility and pliability of muscles and tissues.5 The use of heat is especially effective when combined with stretching and physical therapy. For example, many yoga studios choose to heat their rooms to aid in muscle relaxation and improved flexibility.
When swelling or inflammation is present heat is contraindicated, as it may exacerbate these symptoms. This explains why heat is best used after the acute phase (3-5 days) following an injury. Heat also poses a risk for skin burns and other tissue damage if used incorrectly.
When and How to Use
The most common modalities for delivering heat therapy include heating pads, warm towels, saunas, and hot baths. Apply heat pads no sooner than 72 hours after an injury to avoid increasing inflammation and swelling. Heat pads should be applied for 20 minutes at a time with at least one hour in between sessions to provide the skin adequate time to recover. Only use moderate heat temperatures to avoid sweating, discomfort, and burns. Do not apply heat to broken or damaged skin, and be cautious of any adverse skin reactions, such as excessive redness, rash presence, or raised areas. Consume water and electrolytes before and after using heat therapy to counteract any fluids lost through sweating.
Cold vs. Heat Therapy
The table below summarizes the key differences of cold and heat therapy and provides guidance for proper usage of each.
Ice and heat are beneficial for treating orthopedic injuries. Proper knowledge of when and how to apply each modality can greatly improve the effectiveness of musculoskeletal recovery. Despite the positive aspects of ice and heat for recovery, these modalities are best used in conjunction with physical therapy rehabilitation. Please contact your SHIFT physical therapist team (email@example.com) if an injury is significantly affecting your lifestyle or if you have any additional questions on the use of ice and heat for recovery.
In Real Health,
Scott Robin PT, DPT & Avis Jason, PT, DPT
- Malanga GA, Yan N, Stark J. Mechanisms and efficacy of heat and cold therapies for musculoskeletal injury. Postgrad Med. 2015;127(1):57-65. doi:10.1080/00325481.2015.992719
- Wang ZR, Ni GX. Is it time to put traditional cold therapy in rehabilitation of soft-tissue injuries out to pasture?. World J Clin Cases. 2021;9(17):4116-4122. doi:10.12998/wjcc.v9.i17.4116
- Kwiecien SY, McHugh MP. The cold truth: the role of cryotherapy in the treatment of injury and recovery from exercise. Eur J Appl Physiol. 2021;121(8):2125-2142. doi:10.1007/s00421-021-04683-8
- Masato Kawashima, Noriaki Kawanishi, Takaki Tominaga, Katsuhiko Suzuki, Anna Miyazaki, Itsuki Nagata, Makoto Miyoshi, Motoi Miyakawa, Tohma Sakuraya, Takahiro Sonomura, Takamitsu Arakawa. Icing after eccentric contraction-induced muscle damage perturbs the disappearance of necrotic muscle fibers and phenotypic dynamics of macrophages in mice. Journal of Applied Physiology, 2021; 130 (5): 1410 DOI: 10.1152/japplphysiol.01069.2020
- Freiwald J, Magni A, Fanlo-Mazas P, Paulino E, Sequeira de Medeiros L, Moretti B, Schleip R, Solarino G. A Role for Superficial Heat Therapy in the Management of Non-Specific, Mild-to-Moderate Low Back Pain in Current Clinical Practice: A Narrative Review. Life. 2021; 11(8):780. https://doi.org/10.3390/life11080780