We tend to think that staying hydrated is a simple thing: You drink 8 oz of water per day and you’re all good!
Or there are the more serious folk who are looking at drinking a full gallon of water per day.
Well, I hate to tell you, but it is more complex than that.
Ever since I started training for my Ironman last year, hydration is something that I’ve had on my mind almost every day. It’s more than keeping your pee a certain color: It can dictate how you perform for a competition or race that you’ve been training for, for months or years!
Disclaimer: This does not constitute medical advice, so please consult with a medical professional before you go tampering with your fluids and electrolytes!
With that being said, I found this great article: Practical Hydration Solutions for Sports written by Belval L.N. et al. and decided to do a review, outlining some of the big points of this article that can help you understand, and implement, hydration for your benefit!
So here we go!
Practical Hydration Solutions for Sports (Belval L.N. et al).
When it comes to staying hydrated, we tend to think “I’ll drink when I’m thirsty,” but thirst is not the best indicator of dehydration, especially since tiny deficits (not picked up by thirst) may already be contributing to a decrease in performance. We want to think of both euhydration and dehydration.
Euhydration is the state of hydration that is essential for someone to perform the basic physiological processes to stay alive. Exercise can obviously influence its level and lead to a state of dehydration, which can negatively affect exercise performance.
So, what is optimal hydration? According to this article it is defined as “avoiding losses greater than 2-3% of body mass while also avoiding overhydration.” We want to take in enough fluids to avoid being dehydrated which sounds simple enough; however, there is also the problem of taking in excessive fluid and becoming overhydrated. In severe cases, this overhydration may lead one to develop hyponatremia (McDermott B.P. et al) where your sodium levels are too low, leading to detriments in performance and an increased risk of other serious health issues.
With that being said, it is recommended that in order to maintain good hydration one should:
1. Be properly euhydrated before exercise,
2. Prevent dehydration during exercise, and
3. Replace what has been lost prior to the next exercise session.
Makes sense, right? But it’s more than just pounding one gallon of water each day. Fluid needs are based on a plethora of factors such as:
1. Sweat rate: Do you have to spend 5 minutes mopping up a puddle of sweat underneath your stationary bike after a 90 minute ride like I do? Or can you basically wear the same workout clothing for one week without washing it? (Gross).
2. Exercise structure: # of workouts per day, repetitions, intensity, duration, etc…
3. Fluids: what’s their temperature? How available are they?
4. Type of sport: Are you having to cut weight to make a certain weight class, or will you be exercising non-stop for 12+ hours while doing an extreme endurance event?
5. Environmental conditions: What’s the outdoor temp? Is it humid or dry? What’s the altitude?
6. Clothing: Is what you’re wearing making you sweat more or is it cooling you off?
So where can we start? According to this article, “A comparison of body mass pre- and post-exercise will help guide the athlete in understanding whether their hydration strategy during activity was effective in achieving acceptable fluid balance as well as knowing the volume of fluids that are needed following exercise to return to baseline hydration levels prior to the next exercise session.” So basically, weight yourself naked and dry, BEFORE the exercise, weigh yourself naked and dry AFTER the exercise, and take into account how much fluid you ingested DURING the exercise.
For example: If I weighed 140lb before exercise and weighed 135lb after, then I have a difference of 5lb of fluid that I lost. However, if I also drank 2lb of fluid during the exercise, it’s actually a 7lb difference that I lost during the exercise.
Typical fluid loss through sweat is 0.5 – 1.9L/h (Baker L.B. et al) and there is a wide variability between individuals. Exercise intensity and total duration of the activity are highly influential to the amount of fluid loss. In sports that are more steady-state (e.g. endurance sports), it may be easier to calculate. However, in sports such as mixed martial arts or wrestling, where you have periods of rest sprinkled in with very high bouts of high intensity, one may have to calculate an overall average of exercise intensity.
Environment:
What type of environment are you training in, and what type of environment will your competition/race be in? This area is known for being DRY AF, with some altitude. My Ironman was in Texas, pretty close to Houston. Obviously the environments are very different and my body surely felt it during that run which was hot, humid, sunny, and without much wind. Basically, a field day for dehydration. This is why I blasted myself with a space heater for a 4 and a half hour bike ride on my indoor trainer, so that I would know how to hydrate myself in that heat.
DISCLAIMER: THIS IS NOT WHAT I RECOMMEND PEOPLE DO. I KNEW I WOULD BE ABLE TO TOLERATE IT BECAUSE OF MY EXPERIENCE IN PROLONGED HEAT AND HUMIDITY, SO DON’T GO BLASTING YOURSELF FOR 4 HOURS WITH A SPACE HEATER. DON’T BE DUMB.
However, the cold and higher altitudes are not to be ignored! Exercising in the cold can also produce a LOT of sweating (especially if you’re layered to stay warm) while dampening the thirst response (O’Brien et al.), so basically, you’re still sweating a lot but because you don’t feel thirsty, you don’t drink as much. Oops.
Clothing:
What are you wearing? Or maybe you’re into streaking. I don’t know. Either way, clothing creates insulation and therefore makes it harder to dissipate heat compared to being non-clothed, which I wouldn’t recommend unless you want to get to know the men and women of RPD and the sheriff’s office a little better. With this being said, some research demonstrates that synthetic garments (e.g. polyester) can increase fluid loss compared to cotton garments (Hooper D.R. et al), so you may want to base your clothing on more than what matches your shoes.
Fluid Availability:
What does the availability of fluids look like? Are you going to a jiu jitsu class where the water fountain is on the other side of the gym and you have to slip on your shoes and get off the mat? If that’s the case, you’re less likely to take in fluids (and not to mention, you’re probably wearing some type of synthetic fabric that makes you sweat, more). With that being said, then you’ll need to be more proactive with bringing your own fluids to class.
Or are you doing a full Ironman where you’re going to be on a bike for 112 miles with aid stations every 15 miles, followed by 26.2 miles of running with aid stations every mile? You may be able to get away with picking up some fluid at every aid station without having to carry an additional 120 oz of fluid on your bike. (I literally did this because I tend to be over-prepared).
Basically, know what you’re getting into so that you can plan your hydration strategy, accordingly. If you’re a slower athlete who doesn’t sweat much but you have access to a lot of available fluid, then you may want to take the necessary measures to prevent drinking too much, since this can increase the risk of hyponatremia (Chorley J et al.).
Type of Fluid:
What are you going to be drinking, and how much of it? Will it be palatable over the course of your event? Ironman Texas provided Gatorade Endurance and water. Luckily, I didn’t have any issues with the Gatorade, itself, but I will tell you that I had a really hard time taking in much else that tasted sweet since I was already inundated with so much sugar. With that being said, you may need to look into less sweet alternatives.
Sweating.
Anyone who has trained jiu jitsu with me probably knows how much I sweat. Sometimes I feel like that scene in Airplane where Ted Striker (played by Robert Hays) literally looks like someone is pouring buckets over his head. If you’re not sure about what I’m talking about then 1. You should watch Airplane! because it’s a classic and 2. Just look up “airplane sweating scene” and you’ll see a bunch of images.
If you sweat more, you’re losing more. Typically, bigger individuals sweat more than smaller individuals (though there are exceptions such as myself). Furthermore, if you’re acclimatized to the heat, chances are you’ll sweat more which will increase your chances of hypohydration (Tyler C.J. et al).
What’s your sport?
Having a background in jiu jitsu and mixed martial arts, I’ve spent a bit of time having to cut weight before my match/tournament. Most of the time, people do this by shedding water via sweating and saunas. Honestly, I don’t want to do this ever again but I can understand why people do it, for they believe that it may give them the upper hand (e.g. a bigger people dropping down to a lower weight class believing that when they rehydrate, they’ll be equal (or better) in performance and size compared to their opponent).
If this is what you want to do, then it’s your party and you can cry in the sauna if you want to. However, I think it really demonstrates the need for smart rehydration strategies so that 1. Your health isn’t totally messed up and 2. You can perform well. Looking back, I would have definitely done my weight cut for my MMA fight much differently, knowing what I know now.
In sports such as cycling and running (where the activity is more steady over a period of time), then the frequency of taking in fluids may be easier to calculate and perform. I know some individuals who set an alarm on their GPS watch so they know to take in fluids at specific intervals.
More details on rehydration and electrolytes will be assessed at a different time but for now, just know that hydration is something you need to PRACTICE. Everyone is different, and there are a lot of variables to consider regarding your training, races, events, etc. The last thing you want is to totally bonk or perform like crap because you weren’t adequately hydrated.
My job as a physical therapist is to have people perform well, and do what they love. Hydration is a part of that!
With that being said, I hope you are now well-enlightened to take your hydration, seriously and learn more about it!
Or are you an active individual who wants to stay active for as long as possible? Reach out, and let's get you crushing your goals!
References:
Baker L.B., Barnes K.A., Anderson M.L., Passe D.H., Stofan J.R. Normative data for regional sweat sodium concentration and whole-body sweating rate in athletes. J. Sports Sci. 2016;34:358–368. doi: 10.1080/02640414.2015.1055291.
Belval LN, Hosokawa Y, Casa DJ, Adams WM, Armstrong LE, Baker LB, Burke L, Cheuvront S, Chiampas G, González-Alonso J, Huggins RA, Kavouras SA, Lee EC, McDermott BP, Miller K, Schlader Z, Sims S, Stearns RL, Troyanos C, Wingo J. Practical Hydration Solutions for Sports. Nutrients. 2019 Jul 9;11(7):1550. doi: 10.3390/nu11071550. PMID: 31324008; PMCID: PMC6682880.
Chorley J., Cianca J., Divine J. Risk factors for exercise-associated hyponatremia in non-elite marathon runners. Clin. J. Sport Med. 2007;17:471–477. doi: 10.1097/JSM.0b013e3181588790.
Hooper D.R., Cook B.M., Comstock B.A., Szivak T.K., Flanagan S.D., Looney D.P., DuPont W.H., Kraemer W.J. Synthetic garments enhance comfort, thermoregulatory response, and athletic performance compared with traditional cotton garments. J. Strength Cond. Res. 2015;29:700–707. doi: 10.1519/JSC.0000000000000783.
McDermott B.P., Anderson S.A., Armstrong L.E., Casa D.J., Cheuvront S.N., Cooper L., Kenney W.L., O′Connor F.G., Roberts W.O. National Athletic Trainers′ Association Position Statement: Fluid Replacement for the Physically Active. J. Athl. Train. 2017;52:877–895. doi: 10.4085/1062-6050-52.9.02.
O′Brien C., Freund B.J., Sawka M.N., McKay J., Hesslink R.L., Jones T.E. Hydration assessment during cold-weather military field training exercises. Arct. Med. Res. 1996;55:20–26.
Tyler C.J., Reeve T., Hodges G.J., Cheung S.S. The Effects of Heat Adaptation on Physiology, Perception and Exercise Performance in the Heat: A Meta-Analysis. Sports Med. 2016;46:1699–1724. doi: 10.1007/s40279-016-0538-5.
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