Cold Plunges: Influencer Craze or Real Longevity Booster?

Most influencers don’t have the most likable personalities. But of course, this gives them the superpower of luring people into hate-watching them. We seethingly consume their content start-to-finish without giving an iota of attention to the substance in it (or lack thereof). For health discourse, it’s actually helpful most of the time to keep influencers in this “so bad it’s good” zone and disregard what they’re advocating for. But on rare occasions, the thing they champion might have merit.

Earlier this year, several (mostly male) influencers took over TikTok with the morning routine trend in which they boasted the lifestyle habits that make them the startling successes they are. Their practices varied, from waking up wearing a red light mask to being greeted by bowing ladies who are just thrilled to be at their service. But most of them featured one constant: the facial cold plunge segment. This ritual of dipping their faces in cold water with ice and citrus fruits inspired a slew of memes.

But could cold plunges, whether facial or full-body, be one of those few instances where influencers are onto something?

Today, we examine everything about cold plunges on the Rejuve.AI blog. We will look at the history, the science, and the practical advice you need to know.

A Practice as Old as Time

Despite current influencer hype, deliberate cold exposure is not a new wellness trend. Its use for health and therapeutic purposes is a practice that spans millennia. The Edwin Smith Papyrus, one of the oldest surviving medical texts, made references to the therapeutic use of cold as far back as 3500 BC [1]. 

Ancient societies from Egypt to Greece used water for medicinal purposes [2]. Hippocrates, around 400 BC, documented the use of cold water to alleviate fatigue and reduce pain [1]. The practice continued through history. The third President of the US, Thomas Jefferson, reportedly maintained his health by soaking his feet in a cold bath every morning for six decades [3].

Fast forward to today, we live in the age of gurus like “The Iceman” Wim Hof, who holds 21 Guinness World Records for his cold-defying feats, such as swimming 66 meters under ice [4]. Curiously, Hof doesn’t believe he possesses special abilities. Instead, he thinks we could all be “Icemen” and benefit from the stress cold exposure exerts on our bodies.

The Science of a Beneficial Shock: What is Hormesis?

To understand how a shock of cold water could possibly be good for you, we need to talk about a concept called hormesis. Hormesis is a biological phenomenon where a low dose of a harmful or stressful agent can actually be beneficial. It triggers adaptive responses in the body that improve health and resilience [5].

Think of it like exercise. A session of intense exercise is a physical stressor. It causes microscopic damage to muscle fibers and temporarily increases inflammation. Yet, the body adapts to this stress. It repairs the muscles to be stronger and improves its cardiovascular and metabolic systems [6].

Cold exposure works in a similar way. The sudden, intense cold is a mild stressor that forces your body to adapt [7]. This adaptive response involves a cascade of physiological and biochemical reactions that may have beneficial effects on the immune system, mood, and metabolism. This is the core principle that turns a brief, uncomfortable experience into a potential health tool. 

The key to hormesis is the dose. The stress must be brief and controlled, enough to stimulate a positive adaptation without causing actual harm.

This Is Your Brain on Cold Water

The experience of a cold plunge begins the instant cold water touches your skin. Your skin is densely packed with cold receptors that send a massive electrical signal to your brain, initiating a powerful and immediate cascade of events. This is the "cold shock response," an ancient survival reflex. Your sympathetic nervous system—the "fight or flight" mechanism—kicks into high gear. Your heart rate and blood pressure spike, and you might take an involuntary gasp of air [8].

Consequently, your brain is flooded with a potent mix of neurotransmitters. Norepinephrine levels can skyrocket by as much as 530%, while dopamine, the molecule of motivation and reward, can jump by 250% [9]. This is the source of the exhilarating rush and heightened alertness that some influencers describe as “taking two espresso shots”.

But that is only half the story. As your body responds to the shock, another, opposing reflex is triggered. This is the "diving response," a mechanism that activates the vagus nerve. The vagus nerve is the main highway of your parasympathetic nervous system—the "rest and digest" system that counteracts the fight or flight response. It sends signals throughout the body to calm down, slowing the heart rate and promoting a state of relaxation [10].

Potential Health Benefits of Cold Plunges

Studies show these powerful physiological responses to cold exposure translate into a wide range of potential health benefits, which we'll plunge into now. However, it’s crucial to note that the body of research is still relatively limited, with a need for more long-term studies using larger, more diverse samples and stronger methodologies.

Heart Health

The cardiovascular system experiences an intense workout during a cold plunge. The immediate shock squeezes blood vessels—caused by sympathetic activation. This action increases blood pressure and forces the heart to work harder. While this is a risk for people with heart conditions (more on that in a bit), it can lead to positive adaptations in healthy individuals. A five-month study also shows cold water immersion can lower LDL, aka “bad”, cholesterol and triglycerides [11]. Over time, thanks to repeated parasympathetic activation, the practice can lead to a lower resting heart rate and improved heart rate variability, which are signs of a resilient heart [12].

Inflammation and Immunity

The body’s inflammatory response to cold is complex. Immediately after a plunge, inflammatory markers can actually increase. This is likely a short-term metabolic reaction, not a sign of harmful systemic inflammation. The anti-inflammatory benefits appear later. Studies show a significant decrease in hsCRP, a key marker of chronic inflammation. Regarding immunity, the evidence suggests a boost. One large study found that people who took regular cold showers reported 29 percent fewer sick days from work [13].  

Metabolic Health

Cold plunges can significantly influence metabolism. The primary mechanism is the activation of brown adipose tissue, or brown fat. Unlike white fat which stores energy, brown fat burns calories to generate heat. This process increases the body's metabolic rate and improves its sensitivity to insulin. These effects may help protect against metabolic diseases [14]. 

Exercise Recovery

Athletes often use cold water immersion for recovery, and for good reason. The intense cold has pain-relieving properties by reducing the speed of conduction between nerves [15]. A review of 17 trials showed evidence that cold plunges reduce delayed onset muscle soreness (DOMS) up to 96 hours after exercise [16]. There is a crucial trade-off, however, for those focused on building muscle. Regular cold plunges immediately after resistance training can blunt long-term gains in muscle size and strength. The cold appears to interfere with the cellular signals that trigger muscle growth [17].

Skin Health

The direct benefits of facial plunges for skin appearance, such as reducing wrinkles, are not well supported by evidence. Most claims are anecdotal. The primary effect on the skin could lie in the sympathetic narrowing of skin blood vessels. This temporarily reduces blood flow, acting like a natural compress to diminish swelling and calm angry, inflamed areas. Following this initial tightening, as the skin begins to rewarm or adapt, a compensatory parasympatheitc mechanism kicks in, leading to a gentle improvement in circulation. This reactive dilation of vessels brings a fresh surge of oxygen and nutrient-rich blood to the surface.

Anti-Aging

Cold exposure may influence the aging process at a cellular level. One key mechanism is autophagy, the body's system for cleaning out damaged cells. A recent study showed that after an initial stress response, a week of daily cold plunges significantly enhanced autophagic activity [18]. This suggests the practice can tune up this vital cellular maintenance process. Cold exposure also increases adiponectin, a hormone linked to improved insulin sensitivity and longevity [19]. Finally, the production of "cold shock proteins" like RBM3 helps protect brain cells and may slow aspects of neurodegeneration [20].  

Know the Risks: This Isn't for Everyone

Alright, so you’ve seen the potential gains of cold water immersion. But before you rush into trying the Wim Hof Method, it’s important to know that, unfortunately, 32 people have died due to this method. So risk of adverse events with cold exposure is always looming.

As leading cold plunge researcher, Dr. François Haman, says:

“This type of exposure is extreme, which means that there is always the risk of creating some damage tissue.”

The most serious immediate risk is cardiovascular. The sympathetic response causes a rapid increase in heart rate and breathing, while the parasympathetic response causes a slowing of the heart rate. The simultaneous activation of these two opposing systems can create an "autonomic conflict" that may lead to irregular heart beats [21]. This is especially dangerous for individuals with pre-existing heart conditions. 

A Practical Guide to Taking the Plunge

If you decide to try cold water immersion, it is important to do so safely. Research suggests some general guidelines for temperature and duration.

Temperature: A range of 10°C to 15°C (50°F to 59°F) appears to be effective for most benefits, such as reducing muscle soreness [22]. 

Duration: An immersion time of 10 to 15 minutes is a common and effective protocol [22].

It is crucial to adapt gradually. Start with shorter durations or slightly warmer water and slowly build up your tolerance. Never plunge alone, and always get out if you feel dizzy, light-headed, or excessively uncomfortable.

Conclusion

So, are cold plunges just influencer madness? The science suggests there is a method to the spectacle. However, as we've seen, the research is still young and requires more data from more people to draw firm conclusions. This is precisely the gap the Rejuve Longevity App is designed to fill. 

It allows users to track and understand how different interventions affect their health. By opting to share their results, they can contribute to a broader scientific understanding, helping to separate the real longevity hacks from the fleeting social media trends.

In any case, it’ll be exciting to follow the growth of cold water immersion research. One thing’s for sure: the more good results come out, the more insufferable influencers will be (and the more we hate-watch them).

References:

[1] Kunutsor, Setor K, et al. “The Untapped Potential of Cold Water Therapy as Part of a Lifestyle Intervention for Promoting Healthy Aging.” GeroScience, 30 July 2024, https://doi.org/10.1007/s11357-024-01295-w. Accessed 26 Aug. 2024.

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[11] Tóth, Štefan, et al. “Effect of Repeatedly Applied Cold Water Immersion on Subclinical Atherosclerosis, Inflammation, Fat Accumulation and Lipid Profile Parameters of Volunteers.” Wiener Klinische Wochenschrift, 2 Aug. 2023, pubmed.ncbi.nlm.nih.gov/37530998/, https://doi.org/10.1007/s00508-023-02246-9. Accessed 5 Oct. 2023.

[12] Jdidi, Hela, et al. “The Effects of Cold Exposure (Cold Water Immersion, Whole- and Partial- Body Cryostimulation) on Cardiovascular and Cardiac Autonomic Control Responses in Healthy Individuals: A Systematic Review, Meta-Analysis and Meta-Regression.” Journal of Thermal Biology, vol. 121, 1 Apr. 2024, p. 103857, www.sciencedirect.com/science/article/abs/pii/S0306456524000755, https://doi.org/10.1016/j.jtherbio.2024.103857.

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[14] Søberg, Susanna, et al. “Altered Brown Fat Thermoregulation and Enhanced Cold-Induced Thermogenesis in Young, Healthy, Winter-Swimming Men.” Cell Reports Medicine, vol. 2, no. 10, 19 Oct. 2021, https://doi.org/10.1016/j.xcrm.2021.100408.

[15] Algafly, A. A, et al. “The Effect of Cryotherapy on Nerve Conduction Velocity, Pain Threshold and Pain Tolerance * Commentary.” British Journal of Sports Medicine, vol. 41, no. 6, 8 Mar. 2007, pp. 365–369, bjsm.bmj.com/content/41/6/365.short, https://doi.org/10.1136/bjsm.2006.031237.

[16] Bleakley, Chris, et al. “Cold-Water Immersion (Cryotherapy) for Preventing and Treating Muscle Soreness after Exercise.” Cochrane Database of Systematic Reviews, vol. 2, no. 2, 15 Feb. 2012, www.ncbi.nlm.nih.gov/pmc/articles/PMC6492480/, https://doi.org/10.1002/14651858.cd008262.pub2.

[17] Roberts, Llion A., et al. “Post-Exercise Cold Water Immersion Attenuates Acute Anabolic Signalling and Long-Term Adaptations in Muscle to Strength Training.” The Journal of Physiology, vol. 593, no. 18, 13 Aug. 2015, pp. 4285–4301, https://doi.org/10.1113/jp270570.

[18] King, Kelli E, et al. “The Effect of 7‐Day Cold Water Acclimation on Autophagic and Apoptotic Responses in Young Males.” Advanced Biology, 27 Nov. 2024, https://doi.org/10.1002/adbi.202400111. Accessed 29 Mar. 2025.

[19] Imbeault, Pascal, et al. “Cold Exposure Increases Adiponectin Levels in Men.” Metabolism, vol. 58, no. 4, Apr. 2009, pp. 552–559, https://doi.org/10.1016/j.metabol.2008.11.017. Accessed 30 July 2021.

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[21] Shattock, Michael J., and Michael J. Tipton. ““Autonomic Conflict”: A Different Way to Die during Cold Water Immersion?” The Journal of Physiology, vol. 590, no. 14, 14 June 2012, pp. 3219–3230, https://doi.org/10.1113/jphysiol.2012.229864.

[22] Machado, Aryane Flauzino, et al. “Can Water Temperature and Immersion Time Influence the Effect of Cold Water Immersion on Muscle Soreness? A Systematic Review and Meta-Analysis.” Sports Medicine, vol. 46, no. 4, 18 Nov. 2015, pp. 503–514, www.ncbi.nlm.nih.gov/pmc/articles/PMC4802003/, https://doi.org/10.1007/s40279-015-0431-7.