Cold Plunges are everywhere, and people are swearing by the benefits of a seemingly tortuous experience, but why? How have cold plunges become the poster child for health, and do we really need them? Today we’re going to dive into the world of cold plunges! By the end of this post, we should be able to determine whether this is a fad we can avoid, or whether it’s truly worth the collapsible cold plunge pool I’m thinking of buying for my living room.
Are cold plunges as beneficial as we think? Let’s find out!
I remember watching my college athlete friends struggle with ice baths after a hard workout. Not a bone of envy was felt as I watched them ease into the absolutely frigid water, remaining in there, shivering, for what felt like an eternity, before quickly rushing out and running for their towels. I remember thinking, “couldn’t EVER be me”, happy to watch the torture from the sidelines.
Now, by some twisted hand of fate, I find myself regularly searching high and low for a budget friendly cold plunge, not something easily found in NYC. Somehow, this thing I absolutely dreaded the thought of doing 10 years ago has become a health conscious necessity!
How did I get here? How have cold plunges become the poster child for health? Do we really need them?
I’ve found myself asking myself these questions multiple times over the last few months, and finally decided, let’s see what the science says!
Today we’re going to dive into the world of cold plunges! By the end of this, we should be able to determine whether this is a fad we can avoid, or whether it’s truly worth the collapsible cold plunge pool I’m thinking of buying for my living room.
Let’s begin with the basics!
What is a cold plunge?
The technical name for a cold plunge is “Cold-water immersion”, and, as the name sounds, it involves putting part or all of our body in water that is colder than our normal body temperature1. Our body temperature is a comfortable 98.6°F, and we start to get a bit uncomfortable when temperatures drop to around 75°F, that may have us reaching for a sweater. A cold plunge typically needs to be 40 to 59°F for us to see changes in our body2,3.
That means we’re dipping ourselves into water 16 to 35 degrees lower than what our body finds comfortable!
What happens to our bodies when we plunge them into these cold temperatures? Let’s find out!
What immediately happens to your body after a cold plunge?
We can think of our body’s response to cold plunges as being two parts, immediate changes that can happen during a plunge, and longer lasting changes that come with repeat plunges. We’ll start with talking about the immediate changes.
Let’s think back to the last time we jumped into a frigid pool of water and the immediate response our bodies had– the gasp for air, the increase in heart rate, the desire to escape3. That’s called a “cold shock response” and is a perfectly natural way for our bodies to respond to the sudden immersion into cold water3.
It’s actually the body activating something called the “sympathetic nervous system”3, a brain to body connection that is in charge of our fight or flight response, the response that usually prepares our bodies to deal with stressful situations or periods of intense physical activity.
The sympathetic nervous system turns on in response to the cold water and tells our heart rates to increase. Along with our heart rates increasing, it tells our blood vessels to get smaller, and the blood to get back to all of our important organs (e.g., heart, lungs, stomach)3,4. The goal of this response is to make sure those organs don’t get too cold. The brain is basically thinking, “we can live without a couple of fingers and toes, but we need our heart”, and this is the body’s way of working towards keeping the organs safe.
The sympathetic nervous system also tells our body to release a bunch of hormones that can help with attention, focus, and overall mood4,5. The huge release of these hormones is why we sometimes experience the feeling of more clarity and a better mood after a plunge, pretty similar to when people describe a runner's high3,6.
During this initial plunge, it’s really important for us to focus on breathing deeply, making sure we don’t hyperventilate and enter a danger zone.
If we can get past the initial cold shock response and keep coming back for more cold plunges, something magical, beyond just a better mood begins to happen in the body.
What happens to our bodies if we make cold plunging a habit?
There are three big changes that may happen in our bodies when we make cold plunges part of our routine, each of which, over time can lead to a healthier and stronger us!
Bare with me as we get into the nitty gritty. These changes are pretty complex and mostly happen in the cells.
Change #1
When we talk about fat we’re usually referring to something called “White Adipose Tissue”. It’s the type of fat that accumulates the most in our bodies and is typically the one we can see from the outside, but there’s another type of fat called “Brown Adipose Tissue”7. We’ll call these white fat and brown fat to keep it simple.
Brown fat is specifically activated by cold temperatures and when activated, begins to break down to produce heat8. Over time, as we repeat cold plunges, the body may start to think we need more brown fat to deal with the new cold environment we’re constantly in, and can start converting our white fat to brown8. This conversion can reduce the overall amount of fat we store, and be super helpful in combating risks for some metabolic diseases 9,10.
Change #2
While it’s pretty cool that cold plunges can tell our bodies to change white fat to brown fat, fat changes can’t get all the glory here. How our cells work also begins to change with repeat cold plunges.
If we think back to grade school biology, one of the main things that was drilled into us was, “Mitochondria are the powerhouse of the cell”. They’re our cell’s battery, creating most of the energy needed for our cells to run.
With repeat cold plunges these mitochondria begin to change. They start to increase in number, size, and health11. These changes make our cells more efficient at working and can lead to us having more energy, a better capacity for physical activity, improved metabolisms, and more mental clarity!
Less fat and more energy? This all already sounds too good to be true, but wait, there’s more!
Change #3
Repeat cold plunges can help cells get better at recycling and removing waste.
Think of the inside of a cell like a city, full of buildings and workers. Over time, garbage can build up, and the cell’s “sanitation department”, a process called autophagy, has to clean it up, throwing some things away and recycling others12.
Cold plunges over time can act like a regular supply and infrastructure revamp for this sanitation department, prompting them to work more efficiently and keep the city in better shape12. With time, this may reduce cellular damage and support overall health, immunity, and resilience.
Overall, these changes sound amazing, but it’s important to note that the impact of cold plunges on the body can vary from person to person. A lot of the evidence showing these changes are from smaller studies or is anecdotal. To really understand the true impact of cold plunges on the body, more research is needed.
Cold Plunges sound great, but are there risks?
I have to admit, as I was researching all things cold plunges I was quickly becoming more and more convinced by the benefits.
It truly sounded like there couldn’t be any possible downsides, but anything that sounds too good to be true usually is.
While uncommon, the biggest risk we face when we jump into cold plunges is the risk of irregular heart beats that can turn life threatening. This happens because along with the sympathetic nervous system, another brain to body connection called, “the parasympathetic nervous system” turns on13. These two systems essentially do opposite things, with the parasympathetic nervous system trying to slow heart rates down and send blood back out to our limbs.
Normally these systems aren’t activated at the same time, but in a cold plunge they can be. These two conflicting systems being activated at the same time can lead to life threatening changes in heart rates and, in extreme cases, death13.
Another risk is drowning3. Drowning may be a higher risk if we’re plunging into cold water in less controlled environments (e.g., lakes or pools), than if we’re at a spa, but is a risk in both settings nonetheless. Basically, if we fully jump into the water, submerging our heads, and experience the gasping reflex that comes with a cold plunge we may swallow the water and run the risk of drowning, something that we can probably avoid if we initially keep our heads above water.
It’s also important to avoid cold plunges if we’re ever under the influence of alcohol or other drugs, both can disrupt the brain to body systems and may increase our risk of irregular heart rates.
Other risks are more limited to people with preexisting conditions, but are important to note.
Cold plunges can significantly increase our heart rate and blood pressure, stressing our hearts, so if you’re someone who is living with a heart condition, you may want to think twice before cold plunging. This can include heart problems, high blood pressure, and other blood flow issues5.
Cold plunges also, obviously, make us cold. So if you’re someone who may be living with a condition that can impair circulation or increase your sensitivity to cold, it may be worth thinking twice before jumping into cold water5.
Overall, it’s always best to consult a doctor before taking the plunge! We should remember to listen to our bodies and never push ourselves further than we should.
What’s the best routine to see the benefits of Cold Plunges?
We’ve evaluated the benefits and the risks of cold plunges, but seem to be skirting around the most important question. How do we actually get these benefits? Is there a routine to follow? What do we do?!?
This is probably the simplest question out of all the questions we’ve answered today, but somehow also the hardest.
Why hardest?
The research is still a bit behind the plunging craze. Cold plunges have blown up more quickly than science has been able to keep up! We’ve had enough time to research all the benefits above, but it will take a bit more time to pin down the best regimen.
Right now the suggested regimen below seems pretty popular:
While these are popular guidelines in the wellness community, it's important to know that researchers are still working to pinpoint the best duration, frequency, and temperature. It’s always best for us to start out with less and gradually work up to longer periods of time as we build our resistance to the cold. This will allow our bodies to reap the benefits at lower risks.
There may still be a lot to learn about cold plunges, but, if we take it slowly and remember our limitations, there seems to be a lot of benefits to taking the plunge!
Written by: Nahdia Jones, PhD
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