Well, if you’re like me and in Canada or certain parts of North America .. winter is coming! The temperatures have dropped and you may still brave the cold and train outside, but you’re probably also starting to get the trainer (or treadmill) ready for some indoor training.

But.. how does that impact how much we should be drinking? Do we really still sweat much outside in the cold?
In today’s podcast, I will answer all that and more:
-How does our sweat rate change when we train in colder weather or when we train indoors (and what are all the factors that do affect sweat rate)
-How much should we drink each day, in the few hours leading up to training and during?
-Warm, hydrating beverages you can drink too rehydrate after a run workout in the cold
-How much sodium do we lose in sweat? How do we know if we need electrolytes or if we are a salty sweater?

Full transcript of the episode:

Hey, everyone. Welcome back to another episode of the The Fuelled Trathlete Show. My name’s Andrea, and if you’re like me and it’s starting to get colder where you are, then you’re going to want to listen to this episode. So we are talking all about how to stay hydrated when you are running or training outside in the cold in the winter months.

And, as I was putting this podcast together and putting the information together for you guys, I started thinking about, well, as seasons change, gets colder, a lot of us are doing maybe more training inside. So we’re heading onto the [00:01:00] trainer to do her bike rides or we’re on the treadmill. So I want to touch on that as well today. How to stay hydrated when you’re training indoors.

So if you’re like me, when I first started running I really didn’t think that I needed to bring anything to drink with me on runs in the winter because it’s cold , I’m not sweating as much. And I remember going for a run as long as two hours with, with nothing to drink and no fuel either. So I definitely would not recommend that. If you are someone who believes as well, that you don’t need fluid when training outdoors, hopefully you’ll start to think a little bit differently after today’s episode. So, what we’re going to touch on is one, how does your sweat rate change when you’re running outside and then when you’re also indoor training? And how can we use that information to figure out how much we should be drinking or what should be drinking and overall, how can we make sure that we’re still staying hydrated in these winter months.

So let’s get into it. So how [00:02:00] does our sweat rate change? There’s so many different factors that affect our sweat rate, not just the temperature outside and sweat rate is basically the volume of fluid or the amounts of fluid that you lose through sweat per hour.

So there’s a wide range. Athletes can lose anywhere from half a liter way up to two and a half liters of sweat per hour. So that super high end is, I would say a lot that’s football players, outside in the heat, very large bodies. I would say from what I’ve seen anywhere from like 0.6 liters an hour up to maybe 1.3, 1.5 liters an hour for the endurance athletes that I work with, but there’s always, = to be people less that and above that. So like I said, it’s more than just temperature. One thing that affects it is how hard you’re working or the intensity of your workouts. So you’re working harder, your body’s producing more body heat and going to be sweating more.

 If the weather’s more hot and humid, So the humidity is going to make [00:03:00] us sweat more, as well as the heat. The type of clothing that you wear, if you’re, again, running outside is really hot, you’ve got too many extra layers on. You’re going to be sweating more.

 Your fitness level, how trained you are. And then also genetics. So genetics can kind of determine the number of sweat glands in your body, how well you’re using those sweat glands. So many different factors. The temperature is just one of them.

So when we look at training outside, I think a couple things to make note of is if we’re kind of dressing ourselves properly, we might have a base layer, hopefully have something that’s kind of sweat wicking, meaning that’s going to take the moisture away from your body. So you don’t feel as sweaty, basically. So more of the sweat is getting trapped in that, into your clothing. And if you don’t feel as sweaty, that’s just kind of, one of the reasons why you may feel that you not need, you don’t need to drink.

The other thing is that the cold suppresses our thirst mechanism. So we’re not feeling as thirsty so again, all these kinds of things, making our body feel [00:04:00] like we don’t need to drink, but we are sweating. And especially if you’re still doing a very hard effort workout outside. The other thing to kind of think about too, is that. we lose more fluids through breathing in the wintertime. So when we’re running outside the air is a lot more dry and it’s colder.

So when we inhale cold, dry air during the act of breathing while we’re training, it’s going to be warmed and humidified, as it passes through a respiratory system. And then as we breathe out, we’re actually losing some water. So it increases water loss through the breathing system, through the respiratory system system.

Okay, so now how do we make sure we’re staying hydrated in the winter? Our thirst mechanism is a bit lower. We probably don’t feel as sweaty, but we are still having sweat losses and fluid losses through breathing.

So I’m going to give you some general fluid recommendations and how to stay hydrated, how to rehydrate afterwards. And we [00:05:00] will get into, how to determine your sweat rate so you can know how much fluids you need to be taking. So I think one of the big things, no matter what the temperature is outside, it’s really important to start your runs

well-hydrated. So if you’re already a bit dehydrated already have some fluid losses through the day because we haven’t been drinking enough, then we’re already a little bit behind. So there’s a couple of different general recommendations for how much we should be drinking per day.

 One could be to take your total weight in pounds. Divide that by two. And then that’s the number of ounces of fluids that you want to drink per day. So for example, 150 pounds divided by two is 75 and 75 ounces. So eight ounces equals one cup. So that’s about. Almost 10 cups of fluids per day. The other way is for women to aim for 2.7 liters of fluid a day, and men 3.7 liters of fluid per day.

Now this is just a cover kind of your [00:06:00] day to day basic needs. You want to add on top of that, what you’re going to be losing through sweat. This includes all different fluids that you drink. It’s not just, doesn’t just have to come from water. It can actually come from tea coffee, sports, drinks, juice, milk. Even if you’re eating fruits and vegetables, this can count towards your fluid intake because they have a high water content. It’s going to be your smoothies or soups.

Then you can start to look at how much fluids you’re drinking before you head out for that run. So again, some general guidelines are about two to three hours before drink 16 ounces or two cups of fluids. Then an hour before you want to try to have at least eight ounces of fluid or one cup. Very general recommendation I would say is, you know, if it’s an hour or less and you are starting that workout well, hydrated, you’re going to drink right after. You probably don’t need to be bringing any fluids with you. It wouldn’t hurt, but you don’t necessarily need to do that, or don’t need to add electrolytes to it. After that runs more than an hour. General recommendation, four to six ounces every 15 to 20 minutes. Which works [00:07:00] out to 16. To 24 ounces of fluids per hour.

So again, maybe more on the low end because we do sweat less in the winter, but we do still need to bring fluids with us.

And then afterwards is also key. So this is a part that we also don’t want to skip because when we drink fluids during training or during exercise, the goal is not to replace a hundred percent and the goal is not to drink more than that. When it comes to afterwards, I would say try to have 16 to 24 ounces of fluids afterwards, right away.

Again, you’re on the upper end of that if you had worked out for several hours or maybe you didn’t replace as much as your fluid loss, but at least having one or two cups could be a good start. And try to have some electrolytes with that, and that can be in the form of so salty foods. I don’t know about you. But when I come home from a run outside the thought or having a smoothie or a cold glass of water[00:08:00] is not very appealing.

So it may help you to have some, warm fluids to drink. That also made me think a little bit earlier you may not want be wanting to drink while you’re running, and it’s cold, you may feel like that water’s going to make you cold.

So put, warm water into your, into your bottles and then take that with you. They’re probably gonna cool as are running, but at least they’re not going to necessarily freeze or get too cool to drink.

So when you come back, some things that you could drink, you could do some broth, so regular chicken broth or bone broth. This is a good way to get some fluids, get a lot of electrolytes like sodium. That’s a main electrolyte we want to replace after training. If you’re someone that likes to have a smoothie, just cause you like to drink it or just your appetite’s not super high, go for a blended soup, like a butternut squash soup. This is a good way to get some possibly carbs and proteins and fluids and electrolytes.

I like really like in the winter to make butternut squash soup . Doesn’t have a lot of protein in it though. So I’ll [00:09:00] actually take a, can of white beans, like either white kidney beans or white Navy beans and blend that into my soup and then that adds some extra protein. So that could be kind of like a good way to start the hydration process, the refueling process. Warmup, and then kind of have a meal. You can do chili chicken, noodle soup, all that kind of stuff. So remember I said the soups, the that broth all that still counts as fluid. You could also even do, a protein hot chocolate.

So a couple of ways to do this, Fairlife chocolate milk or just regular chocolate milk. The Fairlife is just a little bit more higher in protein than regular chocolate milk, but you could just kind of try heating that up and just to a point where it kind of gets warm, but not curdled. You could also make a protein chocolate milk. So, what you can do is grab a glass of milk, regular milk, plant-based milk, whatever you prefer. Add in a scoop of chocolate protein powder. Add in like about a tablespoon of cocoa powder, shake that up in a blender bottle, or if you have a milk frother, that’s [00:10:00] gonna, blend really well. And then you can heat that up further on the stove or the microwave. A lot of that rehydration process and recovery process comes from after the run. And like I said, if you’re like me, it’s just sometimes hard to be drinking some cold fluids, even though I’m feeling thirsty I just don’t want to be feeling cold.

Okay, so now let’s get into training indoors. So winter months are probably spending a lot of time in the pain cave on your trainer or on the treadmill.

 Inside you’re probably actually going to be sweating more than you were than you would be if you were training outside.

So one, it tends to be hotter inside just a hotter environment. Another big thing is that there’s less air flow, so you’re not outside running through the air so that air can flow through us. And it also tends to be more humid. So it was hotter, humid, less air flow. Our body’s just has to work really hard to keep our keep itself at the right temperature so we’re going to be sweating more. One thing that you can do to kind of help mitigate some of that is to use a [00:11:00] fan. It does kind of bring some of that airflow. So same kind of recommendations I would say that I’ve talked about earlier.

One, making sure that you’re starting well hydrated. Twi, your drinking, leading up to your training and then three you’re you’re drinking during. Wouldn’t be a bad idea probably in those. Training sessions that are under an hour to have some fluids with you. If it’s more than an hour, then definitely have some fluids to drink and I would more so say, bring that up to four to eight ounces of fluid every 15 to 20 minutes also with some electrolytes. So indoors, the nice thing is that you probably have some table space around you. You have the ability to, have more fluids with you. It’s important to maybe set some reminders, on your watch or on your phone to be able to remind yourself, to drink, to get into that habit. And, now is a really good time just to kind of get in that habit of drinking. If you’re not already, if you’re trying to [00:12:00] prepare yourself for next year and the race season, getting yourself used to drinking every so often. Make all the bottles that you gonna need for your whole training ride, keeps them in the fridge, take a pause during your ride or onto your run on the treadmill. And to go and grab some more bottles.

So like I said, there’s general recommendations for fluid, but if you want to have a bit of a better idea of how much fluids or how much your sweat losses are so that you can replace adequately or make sure you’re not overdrinking, then you’re going to want to try testing your sweat rate. So you want to do this for a workout that’s about an hour long. Your sweat rates, is going to change depending on the weather and the climate and all that kind of stuff. So you would want to do a sweat rate for a run outside want to do a sweat rate for a ride inside or run inside. So what you’re gonna do is you’re gonna pick your run that’s about an hour that you’re going to do it for. Just before your run, you want to weigh yourself. You want to make sure you [00:13:00] have no clothes on and you want to have already eaten, had your fluids gone to the bathroom. You basically want to do this just before you’re heading out the door. So stripped down and weigh yourself on a scale.

And you’re going to record this weight. And then you want to make sure put all your clothes back on, head out for your run outside or your bike indoors, whatever that may be. Then you want to come back you then want to take all your clothes off.

If you do have some sweat on your body, like you probably will, if you’re indoors and you want to towel dry off as much of that sweat as you can. And then also if your hair is very wet, you want to maybe just try and Squeeze out some of the sweat that could be in your hair. You then are going to weigh yourself.

So if you took in no fluids at all during this one hour session, Then you don’t have to do any steps, but if you do think that you will be drinking during this time, you just want to make sure that you know exactly [00:14:00] how much that you drank. So how many ounces of fluids that you had. Try to do it where you’re not necessarily having any extra food .

So first we want to go back to that starting weight minus our ending weight. And let’s say you lost one pound. Whatever weight, whatever weight you lost you’re gonna multiply that by 16, because about one pound of weight loss is equal to 16 ounces of fluids or about half a litre.

So if you lost one pound, then you lost 16 ounces of fluid. If you ran one hour, you could say, okay, my sweat rate on that run was 16 ounces of fluid. If you drank anything, you want to actually add the volume of fluid that you drank to that amount that you lost. So let’s say you drank eight ounces of fluid and you lost one pound. That one pound loss is 16 ounces.

We’re going to add that eight ounces of fluid that we drank, and [00:15:00] that’s going to give us 24 ounces of fluid lost per hour. So, what that tells you basically is in that type of run. So in that intensity of that run or bike or an in that temperature and climate that’s about how much fluid I’m losing. So, like I said earlier, you don’t want to take this number and say, okay, now I have to drink 24 ounces of fluid an hour.

You don’t need to drink a hundred percent or more. You never want to drink more. When you’re getting close to a hundred percent, maybe 80 to a hundred percent is more going to be during, like half or full iron man, because basically the longer that you’re training the closer to your sweat rate, that you’re going to be drinking because those fluid losses are going to accumulate more and more and more over time. But if you are going out for an hour and a half drank, maybe about half or so of your sweat rate.

 Anywhere from a third to three quarters, depending on how long that training. [00:16:00] Session is going to be. With my clients, I do work on with them especially when we’re looking into race season and we’re trying to plan hydration needs for a race, like either a marathon or half Ironman or full iron man we do sweat rate test, try to do it in a similar temperature that the race is going to be in or a similar intensity as well. And then once we have the information of how much sweat is lost per hour, we can start to figure out, okay, this is about how much we need to be drinking per hour to stay on top of those sweat losses and to not get dehydrated.

 Getting into sodium. So sodium is a bit, different too. So I would say, like I said, over an hour, you want to probably start bringing in some electrolytes into your fluids and unlike, your sweat rate, which can vary into different amounts, the amount of your sodium sweat concentration which basically is the amount of sodium per liter of sweat [00:17:00] is pretty consistent.

So if you do sweat more, you’re going to be losing more sodium cause you’re losing more sweat or more fluid in general, but that concentration of the sodium is probably going to be pretty similar to if you weren’t sweating as much. But when you’re not sweating as much, you’re not losing as much fluids, you’re losing less sodium.

So the research shows us that sodium sweat losses is a pretty big range. It can be anywhere from 200 milligrams of sodium per one liter or 32 ounces all the way up to 2000 milligrams of sodium per liter. So it’s a huge range. The average is about 900 milligrams per liter. So that doesn’t mean that if you lose a litre of s weat that you need to take in 900 or whatever your concentration . You can start to evaluate this on your own, if you’re not doing any kind of specific sweat sodium concentration. Some questions you can ask yourself to determine if you’re a salty sweater or not. [00:18:00] So, if you tend to get kind of white salty stains on your skin or your clothing after training sessions or races, then you might have a saltier than average sweat.

 If your sweat tastes salty or if it stings your eyes. So if maybe if you’re indoors training, you’re probably not wearing a hat. So more of the sweat is going to be kind of dripping into your eyes and he’s kind of stinging your eyes. Or if you have a little cut on yourself, then that again can be salty sweater. If you feel kind of dizzy after, and when you haven’t taken enough electrolytes or if you’re craving salts after workout, that can also, be some signs.

So you may just need some more higher sodium amounts in your fluids during your training. So speaking to what we were talking about, I think if you running outside in the cold an hour or less water should be fine. If you start taking it some fluids for over an hour, you may want to take some, some electrolytes.

So maybe start with about 200 milligrams of sodium per hour that you’re looking at ingesting and then monitor how you’re feeling are you feeling [00:19:00] dizzy, are you really craving sodium? Maybe you need to take in a little bit more during that run, or maybe need a little bit more throughout your day to get your needs. Looking at the indoor training again, because it’s very hot and humid when it’s an hour or less and if you do have a really high sweat rate and you feel that you’re a very salty sweater, you probably want to take in some fluids and have some electrolytes in there at all times on your trainer. So again, start with maybe 200-250mg per hour work and then see how you feel, work your way up if you feel that it’s warranted, depending if you’re, again, you’re feeling.

Okay, so that’s all for today’s episode.

So we touched on reasons why our sweat rate changes in the cold. And the main thing I kind of wanted to get across is that yes, we still do need to be hydrating. So hydrate, well, leading up and bring some fluids with you for training that’s over an hour and you made.

If you want to see how much you need, maybe do a sweat rate analysis. And then look at afterwards, maybe having some warm fluids [00:20:00] to drink after.

And then if you’re doing a lot of training indoors, have a fan to help with an airflow. So you’ll be sweating more than your runs outside and especially if the higher intense that that workout is on your trainer or on the treadmill, the sweat is going to be higher.

 And the same thing with afterwards, have some fluids right away. So you’ve made, you know, it’s cold. You may still want some of those warm fluid options that we talked about. But you could look at, having some liquid with your food so maybe some chocolate milk, a sports drink. You could do a smoothie. Really work on that rehydration process right away afterwards.

Thanks for tuning in to today’s episode. Really appreciate you joining. And if you could do me a huge favor and share this podcast with your fellow runner or triathlete friends, and it also really helped me and it would help more people find the podcast, if you could leave a rating or review.

And yeah, I really appreciate that. So have a great day,happy training and I’ll see you guys next week.