The ultimate guide to cold plunge
What are the real benefits of using a cold plunge?
This sums up the benefits of cold plunging pretty well. However, some of these benefits are more scientifically backed than others
Physical and mental recovery
Although there are scientifically backed benefits of cold plunging, there are almost as many unproven benefits. Here are the facts. Cold plunging became popular due to high performance athletes using it to recover faster and more effectively after events. This has now been concretely proven, in a meta analysis of 17 peer reviewed sources it was found that cold plunging was effective in: reducing delayed muscle stress (DOMS), reducing CK levels (a key indicator of training readiness), improving muscle recovery power. All of which was proven to be effective if you cold plunged within 48 hours intense exercise. (7)
Other benefits have also been tested and proven; for example stress reduction. Researchers found across 11 studies involving 3,177 people ice baths reduced stress 12 hours after immersion. (1) There have been a number of studies that cold plunging can act as a mood enhancer and has been shown to help those suffering from chronic pain. Doctor King, a Sports Medicine physician in the Department of Orthopaedic Surgery, mentioned it can be a great help to some people.
So, stress reduction, mood enhancement and physical recovery are the 3 key benefits of cold plunging which have the most evidence. Often cited additional benefits are: boosting your immune system, improving sleep quality, metabolic boost and activating brown fat causing additional fat burn. These have some evidence but are not as universally agreed upon as physical recovery and stress reduction.
Immune boosting benefits
Probably the benefit with the least evidence is boosting your immune system. However, there is some evidence to support this claim. In a study of 3,018 participants, each were asked to take a specific 30 day shower routine. One group were asked to end with a 30 second cold shower 2 other groups were the control and had a hot shower only. This resulted in a 29% reduction in reported sick days in those that ended with a 30 second cold spritz (4). But those same adults also reported the same rate of infection, they just had greater willingness to bear the sickness and go to work. So there may be something to say for cold plunging training your resilience even if it does not 100% improve your immune system. Similarly, there has been a study involving 60 Egyptian males whose immunoglobulin levels (a key indicator for immune system strength) were monitored after 30, 60 and 90 days of using a cold shower or a hot shower daily (5). Those who consistently used a cold shower showed a significant increase in immunoglobulin compared to the control group, but this is a relatively small sample size.
So in short, there is substantial evidence for cold plunging: improving DoMs, reducing recovery time and reducing stress. There is not substantial evidence for cold plunging enhancing your immune system.
Sleep improvement
Cold plunging can directly help you fall asleep due to the physiology of our circadian rhythm. As we approach our expected bed time our body will begin to lower our body temperature, a key trigger for feeling sleepy. Ergo, cold plunging beforehand can aid in this process. It’s not just that cooling down is something that happens as you get sleepy. It's part of what makes you sleepy in the first place(9). It’s important to time your cold plunge appropriately, taking a plunge 1 to 2 hours before your desired bed time to allow your body to deal with the shock and rush of the cold. There are also claims that the other benefits of cold plunge produce a positive knock on affect on sleep. If you have a reduction of stress, muscle inflammation and muscle stress you are more likely to have improved sleep quality. One study of 12 male high performance athletes found that their sleep had markers of greater athletic recovery when paired with whole body cold plunge immersion(10).
Anecdotally I am cold plunging every day for 100 days to prove or disprove some of these factors, and I have so far found it easier to fall asleep following a cold plunge that evening. Furthermore, in a meta analysis encompassing 11 studies and 3177 participants found evidence of immune boosting affects, sleep improvement, mood boost, physical recovery and quality in life were all improved. ‘However, the current evidence base is constrained by few RCTs (trials), small sample sizes, and a lack of diversity in study populations.’.(8) To put it another way there are trials and research that has been done that support all the benefits of cold plunging but they are not a sufficient body of evidence to say all of these benefits are definitive and universal.
Metabolism boosting and brown fat activation
The physiology of cold plunging and how it affects our fat reserves is very simple. When put into extreme temperatures our body must burn more fuel in order to regulate the temperature, specifically it burns significantly more fat and sugar to do so. The body actually reserves a specific kind of fat to perform this action called ‘brown fat’.As a consequence this raises our metabolism. (11). Here is the leading expert on brown fat activation to explain Susanna Soeberg.
She is probably the leading expert on this topic, if you would like to know more I highly recommend checking her out
How do you get the most out of cold plunging?
In a word: 11°C to 15°C for 10 to 15 minutes within 24 hours after intense exercise 3 times a week.
Although, there is no definitive answer to this question. Cold plunging is ultimately a balance between getting the most of the health benefits by cooling your body to restrict blood flow and not cooling your core body temperature to the point of being dangerous. Ultimately it depends on your own tolerance for the cold and your own goals. Generally speaking, medium duration medium temperature is shown to have the greatest benefits for muscle soreness (DOMS)(6). This is defined as 10 to 15 minutes at 11°C-15°C. For most effective for recovery for exercise again, the study used biochemical markers (CK) and neuromuscular recovery (JUMP). These basically assess how sore your muscles are from being torn and your literal ability to jump which indicates how ready you are to train again due to the bio mechanics involved in jumping. So for efficiency of training recovery the best session is a medium temperatures (11°C to 15°C) for 10 to 15 minutes (6). Although getting to extreme temperatures is popular, there is little evidence lower temperatures yield better results as the body cannot cope with (generally) more than 1 to 2 minutes in these extremes and you increase the chance of cold water shock or muscular ‘cold nip’. From my experience, low temperatures do give you more of a dopamine hit but I find a greater sense of calm in longer session and my body feel less sore if followed by exercise.
Where do you get started with cold plunging?
That part is really up to you. Cold plunging in the sea, in a lake, in an at home tub or a professional grade dip all of them are valid and can have equal positive affects on your body. If you want to get technical about your recovery, being able to track the exact temperature is easier in a man made cold plunge. But you could start at Relaxation Station, come to our site anytime and say the magic words ‘coldness is next to goodness’ and we’ll give you a free cold plunge taster session!
References
2 https://onlinelibrary.wiley.com/doi/full/10.1002/lim2.12 and https://www.tandfonline.com/doi/abs/10.3402/ijch.v63i2.17700 and https://onlinelibrary.wiley.com/doi/full/10.1002/lim2.53
3.https://pmc.ncbi.nlm.nih.gov/articles/PMC8044518/
4.https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0161749
5.https://www.sciencedirect.com/science/article/abs/pii/S030645652400189X
7.Cold water immersion and recovery from strenuous exercise: a meta-analysis
8.https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0317615
9.https://www.edenhut.co.uk/blog-posts/cold-plunge-before-bed
10.Effect of the Depth of Cold Water Immersion on Sleep Architecture and Recovery Among Well-Trained Male Endurance Runners https://pubmed.ncbi.nlm.nih.gov/33870188/
11.Altered brown fat thermoregulation and enhanced cold-induced thermogenesis in young, healthy, winter-swimming men. / Soberg, Susanna; Löfgren, Johan; Philipsen, Frederik E. et al.
In: Cell Reports Medicine, Vol. 2, No. 10, 2021.
