by TC Luoma
Stand By for Some Chilling News
People used to call an ambulance when someone fell through the ice into freezing water. Nowadays, it's called therapy. Does it work?
If you've ever narrowly escaped death, you've experienced an intoxicating brew of hormones and neurotransmitters rush through your body. That's in some ways similar to what happens when you take one of those cold-water immersions (CWI) embraced by the famous and relatively well-to-do. We activate the sympathetic nervous system by embracing the "danger" of frigid temperatures. It's the classic "fight or flight" response.
Just in case you're not familiar with this trend, businessmen, actors, various elites, and wannabe biohackers often start their day by immersing themselves for 10 to 20 minutes in cold plunges chilled to below 59 degrees Fahrenheit that can cost as much as 65 grand. Similarly, athletes, including bodybuilders and lifters, often do the same thing after a workout.
You feel like you're going to die (which you could if you stayed in there long enough) and suddenly, when your nervous system compels you to get the eff out, you feel exhilarated.
Why do this to yourself? The thinking, in the case of the elites, is that their brief interlude as a human popsicle will reduce stress and prolong their lives. Athletes do it to reduce soreness and feelings of fatigue and hasten recovery, presumably by reducing inflammation. Bodybuilders do it in the hopes of improving recovery from eccentric-exercise-induced muscle damage.
I'll grant that you might feel good after playing polar bear, at least temporarily, but unfortunately, you might not be doing yourself any good, particularly if you're a lifter. While there haven't been that many studies of the effects of CWI on resistance training, the few that do exist suggest that it slows down muscle growth.
What's more, certain people should avoid the practice altogether as it might bring on a cardiac event.
Cold Puts the Kibosh on the Training Response
T Nation contributor and Ph.D. type Dr. Brad Schoenfeld and some muscle physiology cronies performed a meta-analysis of the effects of post-exercise cooling and resistance training on muscle growth. While only eight studies met their criteria, the results were telling. In short, CWI appears to hamper muscle gains.
Various factors come into play. One study (Fuchs et al.) found that CWI slowed down muscle protein synthesis (MPS) for up to 5 hours post-dunking.
Researchers also found diminished activation of transcriptional factors involved in ribosome biogenesis and suppressed satellite cell activity. Regarding the former, that just means that there was a work stoppage or slowdown in building new muscle protein. In the latter's case, it means no new muscle cells were recruited from young cellular recruits. Both of those phenomena persisted for up to 48 hours after CWI.
This post-immersion blunting might also be caused by something as simple as reduced blood flow to the muscles, which slows down nutrient delivery.
All the preceding might be precipitated by altering the acute inflammatory response to resistance training, which plays a positive role in muscular adaptations to training. For instance, if you quell inflammation via non-steroidal anti-inflammatory drugs (NSAIDs), you throw a monkey wrench into the anabolic signaling necessary to carry out muscle protein synthesis. The same thing appears to happen after CWI.
Are You Suggesting that Inflammation is Good?
CWI is regarded as beneficial because, in theory at least, it reduces acute inflammation (among other things). It likely does reduce inflammation, but let's make something clear here: acute inflammation is necessary for healing, including the type of healing that occurs after a tough workout and leads to new muscle growth.
Acute inflammation is what happens after an injury like a cut, a bruise, or even after a hard workout. It's not long-lasting, and it's localized.
Contrast this with chronic inflammation, which starts as a gross overreaction to some stimuli that's usually benign. It's like bringing a cannon to a pillow fight. It's what you see in common allergies or gluten sensitivity.
You also see chronic inflammation as a response to the body attacking its own tissues. Examples of this include Crohn's disease, Type I diabetes, and rheumatoid arthritis, and these conditions – along with dozens of others – are collectively known as autoimmune diseases.
The big difference, of course, is that chronic inflammation doesn't stop; it continues against all practicality and logic. It's a toilet that won't stop running; an air conditioner with a broken thermostat that keeps the room at bone-chilling temperatures.
But let's get back to acute inflammation. Let's assume I'm Freddie Krueger and my hand came through this computer screen and scratched your cheek with my razored glove. Opportunistic microbes would attack the exposed tissue within seconds, and cells under direct attack would respond by "calling 911," which, in this case, equates to flinging out an ammonia-like substance called histamine.
A lot of this fluid splashes uselessly onto other cells that are under similar attack, but some of it manages to slosh onto the ultra-miniaturized blood vessels that permeate the area.
The tiniest amount of histamine acts like a cattle prod to these vessels. Almost immediately, they swell and double in size, and in doing so, create holes or gaps in the cellular tissue. These gaps allow a special protein-loaded fluid, always on hand in the bloodstream, to come flooding in. This fluid attacks the invading microbes and smothers them dead.
Through these same gaps, sometimes doubling over on themselves to squeeze through, come ravenous white blood cells called macrophages. Amoeba-like, they extend one "foot" through a gap, fold over, and then suck the rest of the body into the battle area, sort of like a fat man trying to step into a pup tent. There, the macrophages can simultaneously engage and destroy up to 100 bacteria each before they fall victim to their own gluttony and die from their own digestive enzymes.
Later come the antibodies, specifically programmed to attack the invaders in the area.
That whole battle that takes place after a cut or a scrape – the initial responses and the histamine release and the subsequent swelling – is part of inflammation. It's a tightly choreographed offensive designed to heal the body. The swelling allows the super-hero-like proteins, white blood cells, and antibodies to come charging into the area.
Likewise, this same swelling that affords access by antimicrobial defenses also makes it easier for post-battle chemical factors like growth hormones to come into play. These growth factors stimulate fibroblasts, epithelial cells and endothelial cells (which make new blood vessels) to come to the area and begin the reconstruction process.
You know those macrophages that march in after an injury occurs? They also march in after a muscle is damaged, only in two waves. The first wave comes soon after muscle fibers are injured, and they begin to lyse or dissolve injured muscle fibers. They reach their highest concentration about 24 hours after a workout or muscle injury, and their concentration dwindles after about 48 hours.
Then comes a second surge of non-phagocytic macrophages that bathe the injured muscle fibers in the growth hormone IGF-1, significantly increasing the muscle regeneration rate.
Likewise, exercise-damaged muscle cells release protein molecules called cytokines, which initiate healthy inflammation that results in decreased levels of myostatin, the protein that tells the body to stop growing muscle, in addition to initiating muscle catabolism.
Acute inflammation also brings about a rise in cyclooxygenase (COX) enzymes, which play a big part in initiating satellite cell proliferation, differentiation, and fusion (with muscle fibers).
Do you see the big picture? If you impede or stop inflammation by dunking into a cold plunge, you could very well impede your body's ability to heal, including its ability to heal/grow new muscle. Ice or cold constricts blood vessels, which decreases circulation. It stops all those macrophages and leukocytes and healing warriors from coming in, cleaning up, and rebuilding.
Granted, CWI or ice will help with pain, but what's more important, a momentary lessening of discomfort or healing and muscle growth?
I need to mention, though, that all the studies Schoenfeld et al. looked at involved CWI that took place within 15 to 20 minutes after resistance training, so it's possible that the muscle growth attenuating effects of extreme cold might not be as dramatic if it's done an hour or two after a workout.
However, given what we know of MPS and inflammation, it's not likely the effects would be much different. It might also be different if CWI is done sporadically or on non-training days.
Can CWI be Dangerous?
Some people should avoid CWI completely, regardless of their motivations for performing it.
It might surprise you to hear that the National Center for Cold Water Safety, a non-profit established in 2012 "to reduce the incidence of close calls, injuries, and fatalities due to cold water immersion" warns that sudden immersion in water under 60 degrees Fahrenheit could kill a person in less than 60 seconds.
Remind me, what's the average temp of one of those cold-water plunges? Oh yeah, 59 degrees. Granted, the Cold Water Safety group is more concerned about people who venture forth on cold water, whether their sport is canoeing, fishing, open water swimming, or one of those moolyaks who jumps into freezing water on New Year's Day.
Still their lessons/warnings might apply to the occasional CWI practitioner, too. They warn that plunging the body into cold water can initiate what's known as the "cold shock response," which is characterized by an increase in heart rate, breathing, and blood pressure. Now, normally, that might not be a problem for a healthy person, but people with heart problems should practice caution lest they suffer cardiac rest, die, and turn blue like Jack Nicolson at the end of "The Shining".
It might be a good idea for anyone, regardless of age or health, to acclimate oneself to slightly less severe temperatures before taking the plunge into polar bear territory.
So, You're Saying Cold Water Immersion is Caca?
Listen, I get it. I've fixed hangover headaches by dipping my head into frigid Lake Superior waters. I've bathed in streams formed from melted ice in the mountains of Utah. Hell, I'm a Finn. We take perverse pleasure in baking ourselves in steamy hot saunas and then jumping naked into snowbanks, our red hot kikkelis melting tunnels into the snow that are quickly adopted by arctic weasels as pre-fab habitats.
I get it. It makes you feel good. The shock elicits the temporary increase in mood-elevating hormones and neurotransmitters (beta endorphins and dopamine). And I suppose that's reason enough to do it.
Likewise, the flood of feel-good hormones might temporarily increase focus, concentration, and alertness, and doing it every day may well help quell chronic inflammation, the bad kind.
But for bodybuilders? You might want to think twice about installing a cold plunge, but if you do, consider using it sparingly, lest you chill away muscle gains. The good news, though, according to Schoenfeld et al., is that "findings related to acute responses of resistance training should not be extrapolated to chronic mechanisms of hypertrophic adaptations out of hand."
That means that even if turning yourself into a polar bear after a workout might slow down the training response, it's likely only temporary and that muscle-building activity will likely continue after the effects of the cold water plunge have abated – although probably at a lesser degree compared to resistance training without CWI.
The natural inflammation and soreness fighter:
References
- Schoenfeld, B., Pinero, A., Burke, R., et al. Throwing cold water on muscle growth: A systematic review with meta-analysis of the effects of post-exercise cold water immersion on resistance-training induced hypertrophy, SportRxiv, Preprint.
- Espeland, D, et al. Health effects of voluntary exposure to cold water – a continuing subject of debate, Int Jour of Circumpolar Health, 2022, Vol 81.