Here’s our inaugural swim tips video. The idea for doing this came to me while I was shoveling snow all day on Tuesday!
All humor aside, this is a great way to manage immersion shock prior to swimming in colder water temperatures. Obviously, you need access to snow. But for those of you who don’t have the luxury of snow storms, I’ll be producing a separate video on an equally effective priming technique – the progressive cold shower. So stay tuned!
After your body finally gets acclimated to the colder water, you’ll be surprised at how easily you can complete a 30-minute swim. However, as we have discovered on multiple occasions, your biggest challenge will not be during the swim itself.
As strange as this seems, you will be much more at risk for developing hypothermia during the 10-20 minute period AFTER you get out of the water. This is due to a physiological phenomenon known as the “afterdrop.”
So let’s take a look at what actually happens leading up to and during the afterdrop.
When you first enter the water and begin your swim, your body reacts by constricting the peripheral blood vessels in your arms and legs. This helps prevent heat loss by consolidating your body heat into your core. And as long as you continue with your physical activity, you will easily preserve a stable temperature.
However, once you end your swim and exit the water, your body sends your blood back to the skin to “warm up.” Because your skin is very cold at this point, your blood actually gets colder and is then recirculated back to your core. In essence, your core body temperature actually decreases during this rewarming period in a phenomenon known as the “afterdrop.”
There are two keys to managing the afterdrop:
1) When you end your swim workout, get out of the water right away. Don’t dally around and expose your skin to the cold water while your heart rate begins to drop.
2) Rewarm your core – not your periphery. This means placing warm, dry layers onto your torso and head and getting some hot liquid into your stomach to warm up your core from the inside. You may have cold hands and feet, but these are secondary concerns.
After I get out of the water, I trot back to the car immediately, and my modus operandi is to get out of the wet neoprene as quickly as possible. I’ll start with my hood and gloves, and I’ll immediately place a warm cap on after I dry off my head. I’ll then remove the top part of my wetsuit and throw on a warm, long sleeve shirt or sweatshirt (or two).
Next come the booties and the rest of the wetsuit. After a quick dry off, I’ll swap out my inner swim gear for some warm sweat pants and then start layering onto my torso. By the time I’m finished, I’ll have 2-3 layers underneath my North Face parka along with a thick cap and winter gloves. Plus, I’ll already be drinking the first of many cups of hot tea from my thermos.
But even with all these post-swim preparations, you can still get a pretty mean afterdrop! I’ve had ones so intense that my jaw has locked up and I couldn’t hold a full cup of tea without spilling it all over the place due to the shivering! But, fortunately, if you do all the preparation on the front end, you can keep these experiences to a minimum as well.
Just remember, the key to it all is to keep the heat in your head and torso.
Note - I wrote the first draft of this post last month, and it’s a bit dated given that the lake has already started to warm up. So basically, you missed out on all the “fun” for this winter!
When you let go of the ladder and start to wade out into the lake during the winter, the first thing you want to do is get the hell out as fast as you can. The initial gush of 32F water into your wetsuit is nothing short of overwhelming – especially if you suddenly discover there are tears in the neoprene around the more sensitive areas of your anatomy.
And this is just the beginning.
Unless you plan to backstroke, at some point you will need to get face down in the water. But you may as well be plunging your head into a vat of liquid nitrogen. The moment your face hits the water, you get an excruciating “pins and needles” sensation that triggers an immediate gasp reflex. And the sudden change in temperature disrupts the pressure in your sinuses, causing the most intense ice cream headache imaginable.
Fortunately this only lasts for about 2-3 minutes…
Believe it or not, you can actually acclimate to this experience and reach a point where this “cold shock” has a minimal impact on you. The key to achieving this is two fold – 1) proper pre-swim preparation, and 2) effectively managing the experience in the moment.
In the previous post in this series, we went into detail about point one. And I can’t emphasize enough how much easier it will be for you to swim year round in the lake if you adequately prepare accordingly. But I won’t candy coat it for you – there is no way you can completely eliminate the shock of entering and remaining in the lake under these temperature extremes.
The key, then, is to effectively manage the first few minutes of this “shock zone” so that your winter swim is an invigorating challenge that excites and inspires you versus a horrifyingly painful ordeal that you don’t care to repeat. And as we touched on in earlier posts, this involves getting your physical and emotional brains on your side.
So let’s take a look at each area.
1) Cold water priming - Ideally, you’ve already done this with a progressive cold shower about an hour before the swim start. However, if you get a late start, you may not be able to fit this in before your swim. Fortunately, there is a quick fix you can do to help take the edge off the initial immersion shock.
Take a bottle of cold water and pour it on your head, face, and neck shortly before entering the water. You can store one in your fridge and grab it on your way out to the lake. Or you can bring a large tumbler and dip it in the lake to do the same thing. In either case, you’re priming your skin temperature receptors which will immediately start acclimating your body to the colder lake temperatures.
2) Mammalian Diving Reflex – This is a very effective technique I do immediately before entering the water, usually while I’m still hanging onto the ladder. It involves holding your breath and submerging your head and neck in the water. This triggers an automatic reflex that immediately lowers your heart rate and sends a signal to your brain to start moving blood away from your periphery and towards your core (head and torso).
3) Mindful relaxation – Once in the water, you will want to pay special attention to the level of tension in your neck, shoulders, and arms. The large muscles in these areas tend to seize up immediately and stay very tense upon initial immersion. So make a conscious effort to relax these areas. Because if they stay tense, your heart rate will stay elevated and you’ll burn off a lot of energy – and energy conservation is key to swimming effectively in colder temperatures!
4) Mindful breathing – Closely related to the prior point, make a special effort to take longer and deeper breaths versus short and shallow ones. This will be difficult at first since you will probably experience a “gasp reflex” which will shorten your breath temporarily. But stay aware of your breathing during the first few minutes and transition to longer and more controlled breaths as soon as possible.
1) Think “2-minutes” – Once you manage to get control over the physical shock of cold water immersion, your biggest challenge will be managing your emotions. Your logical brain, somehow present just a short while ago, will be conspicuously absent. Instead, you will likely be in a highly emotional “fight or flight” state where you are very susceptible to forming associations and memories.
The key here is that you want to form positive ones.
The best way to do this is to perform all the physical techniques cited above while thinking “2 minutes” over and over in your head. During this time, the discomfort on your face and head will subside, and the cold water in the wetsuit will warm up. When this happens, things will stabilize for you physically and you will actually become quite comfortable in the water.
This is the critical “breakthrough” moment.
When you reach this point, you will immediately begin forming healthy and positive associations and memories to winter swimming. And this forms the “success foundation” for practically all of your future lake swims.
So now that you’re acclimated to the frozen lake, you’ll find that you can conduct a fairly lengthy swim workout rather comfortably. As a result of all these preparations and techniques, your body is now optimized to operate efficiently and effectively in this setting. Your heat is concentrated in your core, yet you’ve created a warmer layer on most of your skin surface that you are maintaining through your relaxed physical exertion.
The only downside now is that your fingertips might start to get cold since your body heat has moved towards your core and away from your periphery. Candidly, that’s really the only current challenge we’re having right now during our winter swims. And, of course, you still have to experience and manage the dreaded afterdrop once you finish your swim!
But that’s the next (and final) piece in this series.
As noted in a prior post, 80% of the challenge involved with swimming for extended periods of time in the open water involves managing our physiology and our emotions.
And of these two, managing our physiology is the key factor when swimming in the sub-40F zone.
According to Dr. Alan Steinman, former U.S. Coast Guard Surgeon General and rescue physician, there are three phases to our physiological response to cold water immersion:
1) Initial immersion and the cold-shock response (1-4 minutes) – Rapid skin cooling that causes an immediate gasp response, hyperventilation, and the inability to hold a breath. Concurrent responses included peripheral vasoconstriction and increased cardiac output, heart rate, and arterial blood pressure.
2) Short-term immersion and loss of performance (5-30 minutes) – Continued skin cooling causing compromised neuromuscular activity and loss of fine motor control.
3) Long-term immersion and the onset of hypothermia (30 minutes+) – Apathy, amnesia, and loss of consciousness followed by cardiorespiratory failure.
Obviously, we want to stay as far away from phase two and three as we possibly can.
So our goal then becomes twofold – 1) Reduce (or eliminate) immersion shock which unduly stresses our cardiovascular system, and 2) limit the skin cooling which leads to neuromuscular dysfunction.
Winter Swimming Series – Part 1: Gear Selection already discussed one way of managing this. However, for the remainder of this post, we’re going to outline some key actions and techniques you can do to further prepare yourself physically for the colder water exposure outside of just selecting your swim gear.
So here goes…
Proper hydration involves more than just increasing your intake of water. It also means decreasing your intake of known diuretics such as alcohol and caffeine. Both of these can adversely impact your body’s ability to manage colder temperatures – even if taken the night before. So lay off the booze and double lattes before you swim!
Get quick and easily digestible energy into your muscles as soon as you wake up because they’ll be working extra hard in the colder water. Stay away from most “sports drinks” that are nothing more than non-carbonated soda with the same crappy ingredients (i.e. high fructose corn syrup). My picks – either Cytomax or Hammer Perpetuem.
These are essential to preventing muscle cramping which can take place as you exert yourself much more intensely in the colder water. My current favorite – Trace Minerals ENDURE. I mix this in with my Cytomax, and it makes a huge difference in my performance. I’ve experimented in the past with Hammer Endurolytes, and they also work well. But I prefer the liquid formulation.
The idea here is to get your body already physically attuned to exercising in the cold water about 1 hour before you even get in the lake. To minimize the immersion shock, I recommend the progressive cold shower technique.
In addition, I also try to do about 3-5 minutes of quick, short-burst full body exercises to get my body out of an anaerobic state. My favorite – burpees.
These are tips and techniques we came up with after much trial and error. They are definitely “field tested,” so feel free to try them out to better prepare yourself for an extended cold water immersion.
Here’s a quick exercise I want you to do right now. Take your right hand and make a fist. Now take your left hand and wrap it over your right one. What you’re looking at is a pretty good representation of your brain. Or rather your three brains – your physical, emotional, and logical brains.
And understanding how these three brains work is essential to your success as an open water swimmer – or your success in just about anything else for that matter.
So let’s take a quick look at each one.
This area encompasses your upper brainstem and is roughly analogous to your right lower arm and wrist in our model. Your physical brain (also known as your “reptilian” brain) consists of several structures that manage and regulate autonomic physical functions such as the following:
- Alertness and arousal
- Breathing and heart rate
- Blood pressure and digestion
- Body temperature and thermoregulation
- Basic survival behavior responses
This area encompasses your limbic system and is roughly analogous to your right fist in our model. The emotional brain consists of several structures that regulate motivation, emotions, and memory formation, and it is instrumental in the following:
- Fear, anger, and aggression (“fight or flight” response)
- Pleasure, reward, and reinforcement
- Memory and learning
- Sensory perception and filtering
- Attentional processing
This area encompasses your neo-cortex and is roughly analogous to your left hand in our model. The logical brain consists of the layer of the brain often referred to as gray matter, and it is instrumental in the following:
- Logic and reasoning
- Problem solving and decision making
- Planning and foresight
- Introspection and creativity
- Performance excellence
So why is all of this important, you might ask?
Because 80% of the challenge involved with open water swimming is in effectively managing the physical and emotional parts of our brains – and NOT the logical part.
In other words, you can set detailed swimming goals and make meticulous plans for achieving them – but all of this will collapse if you can’t get your physiology and your emotions on your side.
Whenever I do a swim seminar or one-on-one coaching, this is typically the first area we cover in detail. And the reason for this is that it’s very easy for an athlete to get accustomed to having his or her logical brain in control whenever they are training in an indoor pool.
Think about it – this is a controlled and structured environment with no stressors or surprises. So you can “logically” pound out your precisely formulated workout without all the inconveniences of wind, waves, cold water, or the myriad of other niceties that manifest themselves in the messy realm of Mother Nature.
The challenge lies when you thrust this logic-based swimming “wiring” into a setting that requires much more mastery of the physical and emotional parts of your brain.
And what usually happens in this scenario is that the stress of the situation overwhelms the logical brain, and the emotional and/or physical parts take over.
So as you can see, understanding and managing the physical and emotional parts of your brain is very often the key to excellence in the open water. And as we continue with the Winter Swimming Series, we’ll re-visit this concept often.
I got zapped with one of the nastiest colds of my adult life over the past 10 days, so I’ve been MIA for most our recent swim outings. However, the upside of this has been that I’ve had much more time to ponder over some ideas I had about adding value to the OWC website – and to all of you cherished readers.
I’ve typically posted more educational and health-related content during these colder months, and I thought it would be a good idea to start that once again. And I felt that the best area to start would be to create a “how to” series on winter swimming – since most of the email inquiries I receive are from people asking for advice in this area.
So over the next few weeks, I’m going to post some detailed pieces based on our experiences and lessons learned over the past three years of swimming during the winter months. Here are the upcoming topic areas we’ll be exploring for our “Winter Swimming Series:”
Part 1: Gear Selection
Part 2: Pre-Swim Preparation
Part 3: Managing the Swim
Part 4: The Afterdrop
Hopefully, you can all glean some insights from these articles and perhaps even join us out at the lake for a swim this winter! So here goes…
When the lake temperature dips below 55F, a strange thing happens – namely, most people decide that it’s too cold to continue enjoying the fun and adventure that accompanies outdoor swimming. And that’s a shame, really, since it doesn’t have to be that way.
The truth is that – with the right equipment and preparation – you can comfortably swim and train in the lake year-round.
For Part 1 of this series, we’re going to look at what type of equipment you might need to accomplish this. I say “might” because everybody has his or her own level of tolerance to various temperatures. So while one person might be able to swim comfortably in 45F or below water temperatures in just a swimsuit, cap, and goggles, for others this is nothing short of a Herculean challenge.
So for this post, I’m going to describe a gear setup that we’ve settled on after much experimentation. You may find the need to adjust up or down based upon your own physiology and tolerance to colder water. But we’ve found that this works for most people who’ve come out and braved the lake with us during the coldest months.
My inner layer is essentially the same thing I swim with during the warmer months:
1. Sports “dri-fit” underwear
2. Swim jammers
So basically, wear your normal swimwear or swimsuit as your “base” layer. I used to wear a thermo rash guard underneath as well, but I’ve found that you really don’t need one as long as you have a decent wetsuit. Speaking of such…
1. Full Body Triathlon Wetsuit
It’s important to emphasize using a triathlon wetsuit versus a scuba wetsuit or a windsurfing wetsuit. The latter are not designed for swimming comfortably for extended periods of time. So you want to make sure you use one designed specifically for distance swimming. These typically have 5mm neoprene on the front areas for bouyancy with thinner layers (3mm) on the arms, back, and neck area for enhanced mobility.
But which brand of wetsuit is the best?
I get a lot of people asking which brand of triathlon wetsuit works the best for winter swimming. To be honest, I’m still figuring that out. From my understanding, all wetsuits are pretty much manufactured using the same types of neoprene. The key differences typically lie in the design and fit. So it’s important to try out various brands to see which ones work best with your body style.
One thing I can recommend, though, is to NOT invest in one of the more high-end (read expensive) wetsuits if you plan to swim during the winter. These tend to be constructed with much thinner neoprene and are much more prone to nicks and tearing – which are an enhanced risk during the winter months given the presence of ice in the water. So I’d advise going with the “clunkier” lower end models versus dropping seven bills on a snazzy wetsuit that collapses like papier-mâché in the cold water.
2. Neoprene Dive Hood (3mm/5mm)
These work great for swimming, and we’ve been able to get by with the standard varieties. I tried out a 7mm drysuit hood, and – while definitely quite warm – it was way too constrictive around my neck.
I wear a regular latex swim cap underneath the dive hood for an extra layer of warmth and to keep to colder water out of my ears. Other swimmers just don the hood and use silicone earplugs. Either way works.
One other item – for two seasons, I insisted upon tucking the hood bib into my wetsuit. I did this because the 32F water seemed like hot piano wire on the exposed band of skin around the base of my neck. However, this greatly reduced my swim range of motion and often let in cold water through open areas in my wetsuit neckline.
I’ve since switched to having the bib loose, and I’ve acclimated pretty easily to the cold water exposure on my neck. So I now recommend gutting it out the first few times in favor of a better overall swim experience.
3. Neoprene Dive Booties (5mm)
We’ve all had great luck with the 5mm booties. They seem to work pretty well in keeping our feet warm during the swim. Plus they’re pretty flexible and allow us to maintain a fairly decent swim stroke and kick.
I’ve experimented with two types – the zip up variety as well as the pull ons. The former are much easier to get on and off – which is a HUGE asset in the parking lot when you need to get out of your wet gear ASAP. But the zippers can chew away at the bottom of your wetsuit and shorten its lifespan considerably. They can also come unzipped during the swim causing a horrifying rush of cold water around your ankle that requires some pretty funky in-swim maneuvering to fix.
So we’re still experimenting with these.
4. Neoprene Dive Gloves (5mm/7mm)
This is an area where we’re also still experimenting. Nick and I use the XS Dry Five 5mm gloves. They’re slip ons, but they do a pretty good job of keeping out the water if placed on properly. The problem is that it’s often ridiculously difficult to put these on with one hand already gloved.
Dave and Mike use Deep See 5mm scuba gloves with velcro wrist fasteners. I used to use these and might go back since they are easier to put on and adjust. However, we all still have issues with cold fingertips during our swims, so what we use going forward might change once we find a better solution.
When I first started out swimming in the sub-40F water, I used a full-face Cressi freediving mask. However, since I’ve become much more acclimated to the cold water on my face, I now use a pair of wider view swim goggles – like Barracuda or AquaSphere. I put them on over my hood, and so far they’ve worked fine without leaking.
So there you have it!
This is the current setup that we use when we swim for 20-40 minutes in lake temperatures below 40F. And other than having numb fingertips on occasion, this setup works very well. We’re comfortable during the swim, and we can get in a challenging open water swim workout without over-stressing our bodies.
NEXT IN THE SERIES – Part 2: Pre-Swim Preparation
Be sure to keep checking the site for the next article in this series. In this one, I’ll go over the physical and psychological preparation you need to do to make the transition to swimming in these more extreme conditions. Many of these tips and techniques will also help you with acclimating to water temperatures that might not be as extreme – but are still colder than you’re comfortable with right now.
“So many things can go wrong in an open-water swim,” Dr. Stuart Weiss, the New York City Triathlon medical director, said last week. “There’s some combination of water, adrenaline, pushing yourself hard, and all these things somehow work together to put people into an abnormal heart rhythm.”
Two years ago, after yet another reported triathlon swimming fatality, I highlighted what I believed to be a growing area of concern for the endurance sports community:
We’ve gone beyond this being an incident or a series – we now have an established pattern. I personally think it’s high time the endurance sports community recognizes this potential risk and addresses it during both training and events. In other words, we need to look more at how we’re preparing people to manage both open water swimming conditions as well as the high stress/anxiety scenarios inherent with triathlons.
I still stand by these comments.
The bottom line is that triathlons have exploded in popularity over the last five years, and legions of event organizers and triathlon coaches have sprung up all over the country trying to service this demand.
But unfortunately, there is very little science-based training given to amateur athletes in the critical area of pre-race and in-race heart rate management.
Whenever I do individual open water swim training, the cardinal point that I hammer home to my clients is the importance of effectively monitoring and managing your heart rate – and by extension your respiration rate – at the front end of the swim. I explain the science and physiology behind immersion shock, hyperventilation, and panic, and I teach specific techniques to manage one’s heart rate to avoid the downward spiral into such niceties as sinus tachycardia and drowning.
Why? Because you can learn all the latest swim techniques from any number of certified triathlon coaches. And you can drill for hours on end in the pool.
But none of this really matters if you can’t effectively manage your own unique physiology within the highly uncertain – and often chaotic – environment of open water swimming.
1. Water enters the lungs of a person triggering automatic spasms to the larynx
2. These spasms temporarily seal the air pipe in order to prevent additional liquid from entering the lungs (a natural defense mechanism)
3. This “choking” sensation triggers a panic response which accelerates the person’s heart rate
4. An accelerated heart rate coupled with a sealed air pipe causes generalized hypoxia, an inadequate supply of oxygen to the body as a whole
5. Deprived of oxygen, the person’s cells shift to anaerobic metabolism and flood the muscles with lactic acid, causing rapid fatigue which quickly leads to exhaustion
6. Unable to remain afloat, the person inhales additional water which accelerates the above cycle
7. The continuing oxygen deprivation leads to cerebral hypoxia causing unconsciousness
8. As the person loses consciousness, the larynx relaxes allowing the lungs to fill with water
End Game – Unless rescued at this point, the person dies from either advanced cerebral hypoxia or myocardial infarction (heart attack)
Not drowning is also just as easy.
The key is to interrupt this lethal cascade of events as early as possible – and one of the best ways to do this is to become comfortable with the technique known as drownproofing.
One of my biggest beefs with the endurance sports community is that they never seem to teach this as part of their open water swim training (as least I’ve never seen it being taught anywhere). Instead, they teach you how to tread water, swim faster, sight in open water, and navigate the chaotic scrum of the swim start.
But never how not to drown in the first place.
Whenever I work one-on-one with a swimmer for an open water lesson, the first thing we go over is drownproofing. I make sure they’re comfortable handling any situation that might potentially trigger the drowning process.
And drownproofing is really easy to learn – even a small child can do it:
So the next time you’re out in the open water with your swimming or triathlon training group, be sure to ask everyone whether or not they know how to drownproof.
And if the coaches don’t teach it – or if they don’t know what you’re talking about – you have my permission to nail them on it…
NOTE – Here’s a timely piece for all you “pool rats” out there who are just beginning your training out in Lake Michigan.
If you spend all your time training in a swimming pool, you really miss out on the fun experience of swimming in choppy, wavy water. And yes – you did read that right. It can be a heckuva lot of fun as long as you approach it prudently and armed with the best possible information.
So here are some tips:
Swimming out in the elements means forgoing the static, artificial environment of a swimming pool. It also means leaving a calm and controlled setting for one that can be highly unpredictable and even chaotic. As Dave notes:
Panic sets in once you realize that the surface is not flat, that it’s difficult to spot a point in the distance to aim for, and that the water is not clear. So it’s like swimming in a fog while looking in the water, which can be quite freaky.
The key theme here is control. In a swimming pool, everything’s controlled for you. The water is calm, clear, and temperate. You’re never more than a few feet from the edge of the pool, and you can see and touch the bottom at all times. You are essentially exercising in a very large bathtub.
Out in the lake, there are no such safety nets (or limitations, as we like to call them). You give up external control over your immediate environment in exchange for the (fun) challenge of interacting with the elements as they are. So you need to shift your locus of control internally. Namely, you need to give up trying to manage the water and instead focus on managing your reaction to everything.
2) Find the rhythm of the water
Nature may be whimsical at times, but it tends to defer to rhythms, cycles, and patterns that you can use to your advantage if you can just relax and keep your head during the swim. Even in the most ferociously choppy conditions, there is an ebb an flow pattern that you need to identify and work with – not against. Dave again:
You need to learn how to tell when your body is rising and falling in the waves to determine when it might be best to take a breath without the free mouthful of water. And all of these things will make you change your breathing pattern and stroke sequence in order to swim with the chop.
3) When in nature, mimic nature
Have you ever watched the activity patterns of aquatic mammals and waterfowl? They’re all masters at navigating chaotic water conditions because they instinctively know how to move and act in those circumstances. So do you – but all those hours of pool swimming have dulled your animal instincts.
The key is to act primal in the water. This means to throw out your pre-programmed swim/workout routine and apply short-burst, omni-directional movements that conserve energy by working with the patterns of the water – and not against them.
If you look at a seal or an otter, you’ll notice that they take an indirect, angular approach to currents and waves. If the chop is too large, they’ll time it right and dive underneath it versus expending energy fighting it. And they’re also quite adept at snatching a quick breath at any time and from any direction. You need to do this too.
4) Enjoy the adventure
In a nutshell – stop keeping score. This isn’t the high school state swim championship, and you don’t (hopefully) have a micromanaging coach and helicopter parents screaming at you from the beach. Think of it as just another fun adventure that happens to provide you with intense but manageable physical, mental, and emotional challenges – all of which you can brag about when you get together with your unenlightened pool swim buddies!
GET THE EDGE OVER THE PACK!
Call us at +1 (312) 927-0299 or send us an email, and we’ll talk about your specific needs and how we can tailor a training session just for you.
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Ed. – Here’s a repost from 2009. Get out of that damn pool and experience reality as you were designed to do!
As many of you may already know, I am a strong proponent of the health benefits of cold water. My argument for this is simple – cold water exposure seems to trigger positive gene expression. And from an evolutionary standpoint, this makes perfect sense.
It is quite unlikely that paleolithic hunter-gathers – especially those who migrated across several continents during the last Ice Age – would have come across lukewarm or hot water during their daily existence. In fact, our ritual of starting off one’s day with a hot shower is a very new and very unnatural phenomenon.
Here are a few examples of studies where cold water exposure seemed to have a significant positive health impact. Check out the individual links for more details.