Muscle Recovery: Ice or Heat?

An ongoing debate in sports sciences is whether cold or heat therapy is more effective for improving recovery. Although the studies we have on the topic are not conclusive, there are a few interesting findings that I would like to share with you.
–
When it comes to heat therapy, a 2017 study on endurance athletes found that warming up the muscles you just trained to ~38 degrees celsius improves recovery [1]. Muscle glycogen resynthesis also improved after heating the trained muscles. Glycogen is one of the main fuel sources the body uses during high-intensity training, so quicker glycogen resynthesis usually improves performance recovery. Based on this research, you can experiment with having a warm bath or sauna after training. If anything, it could help you relax after working out.
–
Now, about ice baths. Even though using ice baths can slightly benefit recovery, it may also harm long-term adaptation. Using ice baths after training impairs anabolic signaling (this generally results in lower rates of muscle protein synthesis). So if done consistently, ice baths decrease the amount of muscle and strength you gain long-term. A 2015 and recent 2019 study support this [2, 3]. Consistently using ice baths after training reduced muscle growth in the participants of these studies.
–
So if you had to pick between heating or icing your muscles post-workout and the goal is to gain more muscle, your safest bet is heating. But you can also consider alternative recovery techniques like active recovery. 10-minutes of low-intensity cycling post-workout is similarly effective as an ice bath for recovery, without the drawback of lower anabolic signaling [3].
–
References:
1. https://www.ncbi.nlm.nih.gov/pubmed/28980321
2. http://onlinelibrary.wiley.com/doi/10.1113/JP272881/full
3. https://www.physiology.org/doi/abs/10.1152/japplphysiol.00127.2019