Congratulations Jen M. and Jeff W., for completing Saturday’s Lawyer’s Have Heart 10k!
In January, we asked about your interest in a town hall-style dialogue—any question-and-answer session(s) that would better your experience as an MPH athlete. We received many comments, both on the website and via email. Let’s start with one from Jessy C.: why recover in a bath or shower by alternating hot and cold water?
Question One: Recovery and the Contrast Shower
We often suggest contrast showers after a hard workout—repeating cycles of hot water (for two to three minutes) and cold water (for one minute) several times. Contrast showers and baths are reported to be effective in treating delayed-onset muscle soreness (DOMS), or stiff, painful muscles a day or two after training, as well as swelling. Anecdotal evidence from athletes in a wide range of sports, including CrossFit and Olympic weightlifting, attests to the effectiveness of the contrast shower. The question is: what is the mechanism?
The most common purported mechanism is the “pumping action” created by switching from vasodilation to vasoconstriction, and then back again across multiple cycles. Heat causes blood vessels to vasodilate, or become wider, allowing a temporary increase in circulation and an increase in clearance of waste products that contribute to discomfort and swelling. Vasoconstriction, on the other hand, is the narrowing of blood vessels caused by cold application, and it forces an initial decrease in blood flow, controlling hemorrhage and localized swelling.
These effects can best be realized if the tissue is heated or cooled beyond a surface level. Myrer et al conducted two studies (1994, 1997) that demonstrated that hot and cold immersions predominantly impacted superficial muscle temperature, less than one centimeter from the skin, while deeper tissue temperature remained unchanged. The findings in these studies were echoed by Wertz (1998) and Higgins and Kaminski (1998): temperature change in muscle tissue during contrast therapy is not consistently great enough to stimulate the pumping mechanism of vasoconstriction and vasodilation. However, it is important to note that a handful of additional studies with variant protocols is not corroboration; whereas, tens or hundreds of models with similar standards are more sufficient.
Alternatively, the response of lessened soreness from contrast treatment may simply be the combined individual effects of hot and cold therapy. In addition to vasodilation, heat application increases the elasticity of muscle tissue, ligaments and tendons, and decreases muscle spasm, allowing a worked, contracted muscle to release. Aside from vasoconstriction, cold therapy has a large anesthetic effect. Also, a temperature decrease reduces metabolic rate and helps tissue survive hypoxia, or the lack of oxygen to a tissue caused by cellular damage.
Finally, we know that published exercise science often lags behind practice. While the mechanism for contrast baths and showers is inconclusive, this does not diminish the effectiveness of the treatment for many athletes. We encourage you to test this yourself and see if you experience improved recovery (time) from training.
If you would like to do more reading on this topic, please review these two studies:
–Melody and John