Athletes and the human population are continuously pushing new heights and boundaries that can, at least partially, be attributed to the adaptation and modification of training methods they use. However, another aspect of the high-performance level of a modern-day athlete is their recovery modalities – an area that can strongly dictate how efficiently an athlete can compete, and many times affect when they can compete as well.
The optimization of performance isn’t a novel idea, either. Numerous recovery, performance, and training methods exist that are aimed at providing individuals with better ways to manage the increasing stress on their muscles and joints. And, the truth is, we still do not fully understand what’s best, as it’s likely dependent on the individual- the type of athlete they are, the sport they compete in, along with a vast number of other factors.
The discovery and implementation of many of these recovery therapies have not only enabled athletes to recover faster and more efficiently than ever before, but it has also provided individuals with different ways to enhance longevity and performance.
One example of such a recovery therapy is cold to hot therapy, or contrast therapy. This intervention involves near-immediate switching from hot water immersion into cold and brings with it numerous benefits to aid in recovery in performance. This article discusses this recovery strategy in-depth, including what it is, how it works, and the benefits that come with it.
What is cold to hot therapy and how does it work?
Just as the name suggests, cold to hot therapy, commonly referred to as contrast therapy, involves rotating quickly between hot temperatures and cold temperatures to relieve pain, injury, or overexertion of the muscles and joints.
The benefits of ice or cold immersion for injury and pain/swelling management are well defined- the cold temperatures are effective as they induce vasoconstriction of the blood vessels. This narrowing of the vasculature results in less blood flow for a period of time, thereby alleviating inflammatory signals to injured areas throughout the body.
Heat therapy or heat immersion works in opposition to cold therapy. In response to heat, blood flow and circulation increase due to expansion of the blood vessels, known as vasodilation. This effect has the potential to increase nutrient delivery to injured areas throughout the body to improve the healing process, as well as relieve cramps and aching muscles.
Clearly, cold, and hot temperatures induce distinct, beneficial behaviors for our muscles and joints. But what happens when you combine the two methods?
When you combine the two methods – first by applying cold directly to the injured area or by full-body immersion, followed by application/immersion of heat, and then alternating between the two for 1-3 minutes each, research suggests that the injured muscles/joints improve recover significantly faster. This is likely due to a simultaneous reduction in inflammation and swelling, followed by an increase in nutrient delivery to the affected rates at a pace much quicker than normal?
How is cold to hot therapy performed?
While research on the topic of when it should be performed is still up for debate, the current understanding is that the therapy should be applied no more than 24-48 hours after the injury or stress to the muscle/joint occurred.
From here, simply begin with either full-body cold immersion or topical application of a cold pack directly to the injured area for a few minutes. Once the time is up, alternate to a heating pad, sauna, or hot tub for a similar amount of time. Some recommend a light to intermediate stretching during the hot phase as well. To finish the therapy session off, go directly back to the cold therapy and alternate for at least 4 rounds.
You’ll want to finish the session just as you started- with cold exposure. This is to mitigate the inflammation and swelling that can result via vasodilation during the hot phase.
And remember, stay hydrated! The quick temperature changes can lead to dehydration.
What are the benefits of cold to hot therapy?
So, what specifically are the benefits of cold to hot, or contrast therapy? Here, we’ll go through the primary ones using peer-reviewed research to back them up.
1. Significant alleviation of pain and swelling
Previous clinical studies indicate that contrast therapy can dramatically reduce swelling, even more so than hot therapy/exposure, in athletes with Grade I or Grade II lateral ankle sprains1. In the study, patients aged 13-50 underwent multiple sessions (3 days) of local contrast therapy (i.e., therapy only at the injury location) or heat therapy one or two days following the ankle injury. The researchers found that the cold to hot intervention to the ankle increased range of motion and reduced swelling and overall pain.
2. Increased range-of-motion
This was outlined in the previous bullet point, but it’s no secret that injuries- whether it be a pulled muscle or joint inflammation, can significantly decrease range-of-motion of that joint/muscle. Cold to hot therapy strongly reduces swelling to recover that range of motion and movement.
3. Quicker recovery from soreness
Cold to hot therapy has been shown to hasten the body’s ability to recover from muscle soreness following a hard, stressful training session. A clinical study on recreational athletes over 6-weeks found that following a delayed-onset muscle soreness (DOMS)-inducing leg workout, the strength and recovery (as shown by isometric force production) was markedly higher in individuals receiving cold to hot therapy compared to those who were not2.
Cold to hot therapy has also been found to increase muscle strength post-recovery as well. Athletes exposed to contrast therapy had a higher 1-rep max on the leg press, more muscle power (as measured by isometric force), and performed better on the jump squat compared to recreational athletes who were not receiving the therapy2.
5. Decreases inflammation
As mentioned throughout this article, cold exposure causes vasoconstriction and reduces blood flow to injured areas. This reduction in blood flow decreases the flow of inflammatory markers to the injured muscle or joint, thereby reducing swelling and pain.
Recent work by a research group in Belgium found that telomere length, a factor highly indicative of increased longevity, was prenatally increased in fetuses from winter swimmers frequently exposed to extremely cold temperatures3.
Research also suggests that people exposed to extreme temperatures have a protective antioxidant adaptation important for mitigating reactive oxygen species throughout the body. This is particularly important for mitigating our body’s internal ability to deal with stress to enhance longevity as well4. This beneficial effect is likely due to extreme temperatures acutely increasing the expression of heat shock and cold shock proteins in our body5.
Despite the lack of a robust amount of clinical evidence on cold to hot therapy in humans, there have been a few studies done displaying its beneficial effects for recovery, strength, mitigating pain, and overall performance and longevity. The therapy provides the best of both recovery modalities when considering whether cold or hot exposure is more appropriate, so next time you may need to nurse an injury or a particularly sore muscle following a tough workout, give it a try and your muscles will thank you later.
If you’d like to learn more about optimization techniques, including contrast therapy, hyperbaric oxygen therapy, peptides, or anything else, seek out your local biohacking expert. If you’re in the New York City area, stop by Physio Logic in Brooklyn, NY, and ask for Dr. Rudy.