A new study suggests that cold water immersion baths after exercise, also known as cryotherapy, may reduce muscle soreness.
Cryotherapy is an accepted and commonly used practice in sports medicine because it has been shown to reduce the inflammation associated with many athletic injuries. The use of cryotherapy in sports medicine can be as simple as applying an ice pack to a swollen area of the body. It can also be administered with ice massages or cold whirlpools. The cooling of the affected area slows the release of chemicals that cause inflammation and swelling. The cold temperatures also reduce the ability of nerve endings to conduct pain signals.
In a new study, researchers conducted a comprehensive literature search for well-designed clinical trials evaluating the effects of cold water immersion on muscle soreness after exercise. Study quality and data were assessed by three independent authors. Seventeen studies with a total of 366 participants were ultimately identified for inclusion.
Of the 17 studies included, 14 compared the effects of cold water immersion after exercise with a control group. After combining and analyzing the study results, the researchers found that the cold water immersion treatments significantly benefited muscle soreness when compared to the control groups after 24, 48, 72 and 96 hour follow-up periods.
Four of the 17 studies compared the effects of cold water immersion with warm water immersion. The researchers found no significant differences between groups immediately after treatment or at the follow-up periods.
The authors concluded that cold water immersion may reduce muscle soreness after exercise; however, the quality of the studies evaluated was low. Further research is necessary before any firm conclusions can be made.
The mechanism of action of cryotherapy can be divided into three phases, heat transfer, cell injury and inflammation. The mechanism by which cryotherapy destroys the targeted cells is the quick transfer of heat from the skin. Cell injury occurs during the thaw, after the cell is frozen. Because of the hyperosmotic intracellular conditions, ice crystals do not form until -5 degrees Celsius to -10 degrees Celsius. The transformation of water to ice concentrates the extracellular solutes and results in an osmotic gradient across the cell membrane, causing further damage. Rapid freezing and slow thawing maximize tissue damage. The last response to cryotherapy is inflammation, which is usually observed as erythema and edema. Inflammation is the response to cell death and helps in local cell destruction. A thorough cryotherapy treatment causes basement membrane separation, which may result in blister formation.
In addition to cryotherapy, many other integrative therapies have been studied for their potential effects on exercise recovery. Beta-hydroxy beta-methylbutyrate (hydroxymethylbutyrate, or HMB) has been found to reduce muscle damage associated with exercise and to shorten recovery time. Supplementation has been found to inhibit muscle breakdown and enhance protein synthesis. Additionally, several studies of weak design have suggested that massage may benefit post-exercise muscle soreness. However, the data are insufficient to form definitive conclusions.
For more information about integrative therapies for exercise recovery, please visit Natural Standard's Comparative Effectiveness Database.
For more information about cryotherapy, please visit Natural Standard's Health & Wellness Database.
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