Von Collins is an accomplished triathlete and endurance cyclist, and the author of four fitness and training books: Smarter Running, Your First Triathlon Guide, Fit Foods, and 30 Rut-Busting Workouts. He has been cited as a triathlon, cycling, and fitness expert by Healthline, CNET, Forbes, Eat This, Not That and other major outlets.
Cold plunges are popular, in fact they are seemingly everywhere. My big health club now has a 12-person cold plunge pool. The local Crossfit place has a cold plunge next to their sauna. I read of more and more people who created a home cold plunge tub.
Do cold plunges work? And does it make sense for athletes, runners, cyclists, or triathletes to incorporate cold plunges into their workout routine and training plans?
I decided to review as much research as I could find, and here is a summary:
Promising Link Between Cold Plunges and General Health
A recent review suggests that taking cold plunges might be good for your health, but more research is needed to fully understand the benefits. Some areas suggesting promising initial findings are on how it affects the immune system, heart health, insulin resistance, and mental well-being. The researched noted a need to educate people on how to do it safely and understand its specific benefits better. Overall, while there’s some evidence supporting the health benefits of cold water immersion, this study was careful not to suggest that it had all the answers. The debate on its effectiveness will no doubt continue.
Other studies have found that cold plunging increases activity of something calls brown adipose tissue (BAT) which in turn helps burn fat and can have positive preventive impacts against diabetes, in part by activating and regulating one’s metabolism. That could be notable to those who have stubborn bodyfat levels and are trying to break through their training plateau.
Specific Benefits Might Exist of Cold Plunging Right After a Workout
The next study I examined is more directly relevant to endurance athletes. A study from Singapore and published by the NIH found that after intense training or competition, the body gets stressed and tired, but this can lead to better performance later on. When you’re immersed in cold water, the pressure of the water pushes fluid from outside your blood vessels into them, which can reduce swelling in muscles and soft tissues caused by exercise. This also increases the amount of blood circulating in your body, leading to better heart function and blood flow throughout your body. These changes happen without you having to use more energy.
This suggests that cold plunge might be useful after an intense workout, like a hard indoor cycling workout or a triathlon race day. I find I like to do my cold plunges after a good threshold of VO2 max workout where I really spent myself and might rest the next day.
The same study suggested a few other post-workout things that are perhaps more proven than cold plunges, like:
- Rest enough to let your body recover naturally.
- Stretch gently to help your muscles recover faster.
- Cool down gradually instead of stopping suddenly.
- Eat a balanced diet to fuel your recovery.
- Drink enough fluids to stay hydrated.
- Consider getting a proper massage.
Some athletes also use alternate hot and cold baths or contrast water therapy, where they switch between hot and cold water. But more research is needed to understand how effective these methods are and what the best way to use them is. Overall, it’s better to take a holistic approach to recovery, rather than relying on just one technique.
The Benefits of Cold Plunging on Muscle Soreness Recovery are Short-Term
A more skeptical study was done by the American College of Sports Medicine Research. This study compared the effects of cold water immersion versus active recovery after exercise on muscle inflammation, stress, and recovery in humans for the first time. They found that exercise increased inflammation and stress markers in muscles, but using cold water immersion didn’t significantly reduce these markers compared to active recovery. Other studies on animals have shown mixed results regarding the effectiveness of cold therapy for reducing inflammation. The researchers also noted that cold water immersion didn’t affect the expression of certain genes related to inflammation and stress in muscles.
There were some differences between this study and previous animal studies, including the type of injury induced and the comparison with inactive recovery. The researchers found that cold water immersion didn’t significantly reduce muscle soreness after exercise, but it may still have short-term benefits for athletes in terms of reducing fatigue and improving muscle function. However, using cold water immersion regularly might not be good for long-term muscle strength and growth.
Combined with other things like foam rolling, a cold plunge might help athletes be generally less sore between workouts.
Australian Researchers Put Cold Plunging on Par With Active Recovery
A team of Australian researcher found that cold plunging probably helps with muscle soreness but might not be idea for those trying to build new muscle. The study compared how cold water immersion and active recovery after intense resistance exercise affect muscle growth and repair. They found that both methods had similar effects on the genes and proteins involved in these processes. Contrary to previous animal studies, cold water immersion didn’t seem to reduce muscle growth factors or promote muscle breakdown pathways. The results suggest that cold water immersion might not be the best choice for long-term muscle strength and growth, despite its short-term benefits in reducing fatigue and muscle soreness. They believe that regular use of cold water immersion might hinder the body’s ability to adapt to strength training over time.
Perhaps the Most Commonly-Cited Benefit is on the Immune System
Multiple studies suggest that repeated cold plunging might help activate the immune system in a stronger way than not cold plunging. An old study from 1996, for example, investigated if cold water immersion can activate the immune system in young athletes. They found that a single session had minimal effect, but doing it three times a week for six weeks led to small increases in certain immune markers like monocytes, lymphocytes, and tumor necrosis factor alpha. Some acute phase proteins also increased. There was a trend towards changes in other immune markers like IL6 and T lymphocytes. However, markers like IL1 beta, neopterin, and immunoglobulins showed no significant changes. Overall, repeated cold water immersion slightly activated the immune system, likely due to the stress it induces, but the significance of these changes isn’t clear yet.
Cold Plunge Takeaways for Endurance Athletes
It seems that whenever you go down the rabbit hole of various studies, you walk away less certain than before! But here are a few things I would say are takeaways for the endurance athletes reading this:
Cold Plunging Can Relieve Short-Term Soreness
I think there is enough evidence mounting, and lots of anecdotal trending, to suggest that you can reduce short-term soreness by using a cold plunge. What that means for me is that ofter a couple back-to-back hard training days, or perhaps after a long training ride, I might do a cold plunge as I transition into a day or two of rest. It seems to make my legs feel better and give me more “snap” in my step for the rest of the day.
Cold Plunges Might Inhibit Muscle Growth
This applies more to those who are spending time in the trip doing lots of strength work. If you are training for a century ride or marathon, it is likely that you are trying to tone your muscle and train it for distances. But if you are actively trying to build muscle and add mass, be careful with cold plunges. There seem to be enough suggestions that it could inhibit muscle growth, and where there is smoke, there is fire.
Immunity Can Probably Benefit
One of my most optimistic takeaways from the research is that regular cold plunges probably help your immune system, to some degree. This is big for me, because when I get a cold I’m down for the count and my training plan really suffers. If 3 cold plunges a week can help my immunity, sign me up.
If you are new to cold plunging, start slow. There have been reports of people with heart conditions struggling with cold plunges, and other reports of delayed onset muscle pain from people doing too much too fast. I recommend that if it is a normal 45-50 degree temp cold plunge, start with 2-3 minutes. Work your way up to 5, 8, and 10. There is really no reason to do any more than that.