You're More Thirsty in Winter Than You Think - Coach Tip Tuesday

50% of humans worldwide are not sufficiently hydrated.

To put this into perspective: That means that if you are sitting with another person right now, one of the two of you isn’t sufficiently hydrated.

Over the years, I’ve written about and talked about hydration more than any other topic on the blog, on The Full Circle Podcast, and in my conversations with athletes themselves.  The reason for this is straightforward: Hydration is the simplest intervention that athletes can make that will improve both their overall health and their athletic performance.  Nothing is more important than our health, and for athletes, performance is usually running a close second in terms of importance.  As such, I try my very best to encourage athletes to hydrate sufficiently and to treat hydration with the reverence that it deserves.

Yes, there are other things that are significant and important for athletes to do, but the interventions and fixes for those things are a little more complex.  While sleep is critically important, it is generally harder for people to make meaningful changes that rapidly increase the quality or quantity of their sleep.  Consistency of movement and in training is also incredibly important, but like sleep, changes to an athlete’s level of consistency are harder to make and therefore slower to implement.

But making changes to hydration status can be implemented literally immediately (as in by the time you’re done reading this article) and the positive effects from these changes can be felt just as immediately (within a day or two).  However, despite the simplicity of this intervention and this fix, literally half of all people still do not hydrate sufficiently. 

Why is Hydration so Important?

Approximately 60% of an adult human body is water.  (Fun Fact: We start off as 78% water when we are born, and this slowly reduces as we mature through adolescence to settle around 60% when we are adults.)  In an adult human, the brain and heart are 73% water, the lungs are 83% water, the skin is 64% water, muscles and kidneys are 79% water, and bones are 31% water.  (Yes, even bone - one of the most “solid” structures in the body - is composed of water!)  As such, hydration status impacts literally every system in the human body.  Just to name a few: Water plays a vital role in the proper functioning of the circulatory system, the vestibular (balance) system, the digestive system, the adrenal system, the muscular system, the nervous system, and the skeletal system (especially in joint function).  Additionally, adequate hydration status reduces our chances of developing chronic diseases, being biologically older, and dying early.  As athletes, maintaining adequate hydration status helps facilitate adaptations to training and with achieving better performances.  

There is not one single thing that being dehydrated enhances or makes better.  Not one.  But being sufficiently hydrated can help improve the functioning of every system in your body, thereby increasing your chances of performing well in training and racing and achieving your goals.  Its health benefits are numerous; being sufficiently hydrated can also reduce your chance of developing a chronic disease by 64%, your chance of being biologically older by 50%, and your risk of dying early by 21%.

And yet…literally half of people do not hydrate properly.  Why is this?  There’s no agreed upon, definitive, concrete answer, but I have my own hypotheses developed from years of working with athletes and being a human myself.  The most likely reason is that hydration is, in fact, simple.  Consuming water is a very simple action, especially in the developed world where continuous access to clean drinking water is such a way of life that we don’t even consider what a miracle it is or how revolutionary it is when compared with a majority (literally 99%) of human history.  

I’ve seen and experienced first-hand just how challenging it can be for humans to accept that something simple - such as increasing hydration intake - could be the appropriate and conclusive resolution to what appears to be a complex issue or problem (such as joint stiffness, gut issues, headaches, performance declines, and more).  We often mistakenly think that complex problems must require complex answers and solutions.  But this is inaccurate; more times than not, the answers to complex problems are, paradoxically, simple.

Creaky joints?  Getting sick?  Feeling dizzy?  Not recovering from workouts well?  Feeling like you’re fading by the end of a workout?  Not achieving the performance you feel like you’re capable of in a race?  All of these things can - and do! - benefit from looking at your hydration status and seeing if it’s adequate.  If you are not hydrating sufficiently on a daily basis and/or you are not hydrating during your workouts and you are experiencing any/all of these things, then yes, something this simple might actually help make you feel better and be the answer to what ails you.

What is a Good Amount of Hydration?

Hydration needs vary from individual to individual, but there are good general guidelines that all people (and therefore athletes) can start from to help them determine what a sufficient amount of hydration is for their individual body.  The National Academy of Medicine found that women who are adequately hydrated consume an average of 91 ounces of total water per day; they report that men who are adequately hydrated consume an average of 125 ounces of total water per day.  Total water means the total amount of water someone consumes, including water from both beverages and foods.  On average, people get approximately 20% of their hydration from water-rich foods such as soups, fruits, and vegetables, so assuming that those foods are part of one’s daily diet, this means that women need to consume around 72 ounces of water per day via drinking and men need to consume around 100 ounces.

For athletes, it’s incredibly important to note that these recommendations are for “normal” humans who are not athletes training for endurance sports goals.  Endurance athletes are literally extra ordinary; an incredibly small percentage of people - less than 0.05% (yes, less than five hundredths of a percent) - actually train for endurance sports events such as running races, cycling races, and triathlons.  Even if we consider the number of people who run or jog for exercise (versus to train for a goal), only about 15% of people in the United States do so.

Training for endurance sports goals increases one’s need for water, which means that endurance athletes will need to consume more than these baseline recommended amounts if they want to maintain a sufficient hydration status.  Based on my experience as a coach and athlete, I can confidently say that training for endurance sports increases daily hydration needs by a minimum of 16 ounces per hour of workouts.  So if you are an average-sized female who has a three-hour workout on your schedule on a given day, you need to consume at least 120 ounces of water that day (72 base ounces + 48 ounces for your workout = 120 ounces total).

This being said, not all bodies are created equal.  People with lower body mass (aka smaller people) generally have lower hydration needs than people with a higher body mass (aka larger people).  For this reason, a good guideline to start to try and determine your own daily water needs is to take your weight in pounds and divide it by two.  That resulting number is the baseline number of ounces of water you should aim to consume on a non-workout day.  (So for instance, if you weigh 200 pounds, you should be aiming to drink at least 100 ounces of water per day.)  On a workout day, you should be increasing your water intake by at least 16 ounces per hour that you train.  (So using this example, 100 ounces + at least 16 ounces per hour that you exercise.)  To dial this in further, I recommend that you conduct a sweat rate test to determine your own personal fluid losses while you’re training, as your hydration needs per hour may actually be in excess of 16 ounces per hour while you’re doing a workout.

Hydration Needs in Winter

Studies have shown that cold temperatures reduce our thirst sensation by up to 40%.  Thirst sensation is the subjective feeling of needing or wanting water.  Generally speaking, our thirst sensation is a good barometer to gauge if we need water or not.  However, this is not true in the Winter since it is suppressed, so we can’t fully trust it during this time of year.  Thirst sensation is reduced in colder temperatures because the body constricts our peripheral blood vessels near our skin and in our extremities, which forces more blood volume to go away from these areas and into our core.  The body is always prioritizing the most important tasks and body systems to maintain homeostasis as we go about our day.  Homeostasis is the state of steady internal and chemical conditions maintained by living systems.  In other words: Homeostasis is a state of balance among all of the body systems needed for the body to survive and function correctly.

When we are in a cold environment, maintaining an appropriate core body temperature becomes more important than many other things, including maintaining fluid balance, when it comes to maintaining homeostasis.  Rerouting blood and creating a fluid imbalance between different parts of the body is excellent in terms of helping humans stay warm when it’s cold outside, but not so great when it comes to our hydration status, as this rerouting of blood effectively tricks the brain into thinking that the body is sufficiently hydrated, when it is not.  

Basically, since it sees the increase in blood volume at the core, the brain doesn’t detect the blood volume decrease elsewhere in the body that made that increase in the core possible.  This makes the brain (inaccurately) think that all parts of the body have an appropriate amount of fluids and that body is sufficiently hydrated.  Since it thinks it is sufficiently hydrated, the brain doesn’t trigger our thirst sensation.  And this makes us feel like we don’t “need” water or to drink…when we actually do.

As previously discussed, athletes - and humans in general - don't hydrate themselves properly year-round.   So it’s very unfortunate that the Winter season makes it even tougher for people to maintain an adequate hydration status since it triggers false lack of thirst perceptions.  We are actually at a greater risk of getting dehydrated in cold weather since we have a diminished physiological stimulus to drink.  Just because we don’t feel like we “need” water or to drink as much in the Winter doesn’t mean that we don’t.  In order to maintain adequate hydration status in colder temperatures, we need to effectively “override” this sensation and drink anyway, despite the fact we may not feel thirsty.

In a practical sense, what this means for athletes is this: You need to drink a baseline, sufficient amount of hydration every day.  And you need to hydrate every workout you do.  Yes, even in the Winter.  Yes, even if you don’t think you “need” it because you are not feeling thirsty.   As previously discussed, the body is exceptionally adaptable and will go to great lengths to maintain homeostasis, up to and including significantly reducing or shutting down some body systems to prioritize others.  Just because you can “get away” without drinking doesn’t mean that your lack of hydration isn’t costing you somewhere and that you’re not dehydrated.  Yes, you can be dehydrated and still function and exist.  But it comes at a cost: Failing to consume an appropriate amount of water (aka being dehydrated) could be impairing your health as well as your athletic performance.

Tips for Hydrating Well in the Winter

Hydrating well in the Winter starts with the understanding that your thirst cues are going to be reduced and that you are going to have to mentally override that by drinking even if you are not feeling thirsty.  But there are other tips to consider when it comes to being able to hydrate well in the Winter.

Choose Hydrating Beverages

Not all beverages hydrate the same, and not all beverages cue or quench our thirst the same.  Your choice about what beverage to consume can have a pretty significant impact on your hydration status.

Fluids are transferred and absorbed into the body via a process called osmosis.  Osmosis is water movement based on the concentration of water molecules on each side of a semi-permeable membrane; water passes from a side with lower concentration to a side with higher concentration.  This osmosis occurs based on the osmolality (the measure of the concentration of dissolved particles in a fluid) of your blood plasma.  The majority of fluid absorption in the body occurs in the small intestine. 

Beverages with osmolalities higher than blood plasma are hypertonic.  An example of a hypertonic beverage would be something that has a high concentration of carbohydrates and/or electrolytes, such as fruit juice, soda, or alcoholic beverages.  A hypertonic beverage is going to cause water to flow from the bloodstream into the small intestine (which is the opposite direction of what we want and is actually dehydrating).  Beverages with osmolalities lower than blood plasma are hypotonic.  Examples of hypotonic beverages include plain water and diluted sports drinks.  A hypotonic beverage is going to cause water to flow from the small intestine into the bloodstream (which is the direction we want it to go and is hydrating).

This principle is why it’s so important to consider the content and concentration of any beverages you consume, both over the course of a day and while completing workouts.  When seeking to actually hydrate the body, we want to consume beverages that are slightly hypotonic because that will cause the flow of fluids to be from the small intestine into the blood stream, and hypotonic beverages will do this quickly.  This is of particular importance when considering what beverage to consume during a workout, when the speed of rehydration matters more than when we are at rest.

Beverages that contain both some carbohydrate (sugar) and electrolytes are the best choice for in-workout hydration.  Sugar-free beverages are poor choices for mid-workout hydration, but more sugar is not necessarily better; there is balance here.  Aim to choose beverages that have a 4-8% carbohydrate concentration.  Electrolytes are minerals that dissociate into charged particles when mixed into water.  In the human body, electrolytes allow for the conduction of electrical impulses, help maintain fluid balance, and play a role in enzymatic reactions.  Sodium is the most important electrolyte related to hydration and exercise because its concentration in sweat is many, many times greater than other electrolytes (such as potassium and calcium).  Seeking to consume a beverage or sports drink that contains 10-25 grams of carbohydrate per liter and 1,000 milligrams of sodium per liter is a good place to start.

Avoid Cold & Carbonated Beverages

Because beverages do not all hydrate the human body the same way, what you choose to consume not only impacts your actual hydration status, but also whether or not you’ll actually feel like drinking.  Carbonated and cold beverages both quench and reduce our thirst sensation more than “flat” and room temperature, warm, or hot beverages do.  Thus, during the Winter when thirst is already reduced because of ambient temperatures, choosing to consume beverages that are at least room temperature or warmer and uncarbonated is worth considering, as then you will not be further reducing your thirst sensation.

Keep Hydration Easily Accessible

The most common excuse I hear from athletes about why they are dehydrated is that they don’t have hydration with them.  This is another situation that has a simple fix: Do a little bit of pre-planning and keep hydration with you at all times.

Any good habit starts from an “easy” behavior, meaning that you need to make something easy for yourself when you start it if you want it to ultimately become a habit that is more second-nature to you.  When it comes to hydration, keeping vessels with you at all times makes it so that you don’t have the excuse of not having hydration.  If you have it, you’re more likely to use it.  And if you see it, you are less likely to forget to hydrate and/or lose track of time between times when you do hydrate throughout the day.

Throughout your day, keep a refillable water bottle with you.  When you go on a bike ride, put a bike bottle in the cages on your bicycle.  When you go out for a run, carry a hydration vest or handheld with you.  When you go to the pool, bring a water bottle to keep on the pool deck.  When you are doing a strength session, keep a water bottle with you.  You get the idea.  Even if it means a little upfront investment to purchase hydration vessels, the long-term health and performance benefits will be worth it.

The Bottom Line

Even if you don’t feel thirsty, you need to hydrate all year long.  Winter can create a situation where our body is sending us inaccurate signals when it comes to our thirst and hydration status.  In order to have both the best health and performance outcomes possible, you need to override this and consume fluids in all seasons, and most especially in Winter.  By understanding the vital role that hydration plays in your health and performance, choosing hydrating beverages, and keeping fluids accessible to you, you can be in the 50% of humans who are sufficiently hydrated and who reap all of the wonderful benefits of being so.

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Sources:

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