I’m an endurance athlete – how much do I need to eat and drink?
Article by Darryl Griffiths - Shotz Sports Nutrition
Learn what works best for YOU! Here’s a snapshot on how you find that out. It’s about learning numbers specific to YOUR physiological makeup, the intensity at which you compete and how you respond when you experience varying environmental conditions.
This is information related to you because you are one of a kind and you don’t want to leave your nutrition to chance. Understanding that you are unique such as the amount you sweat, the amount of sodium you lose in that sweat, how your sweat rate changes as the weather conditions change and how the accumulative loss of sodium alters as sweat rate changes, your calorie expenditure, the amount of fluid your stomach can tolerate and the amount of calories your stomach can tolerate.
You can learn a lot from this book – Sweat. Think. Go Faster – it’s a must read that covers why you need to separate your calories from your hydration to allow you to customise your nutrition strategy to suit your individual needs and adapt it to the changing environmental conditions.
It would be nice if someone could just tell you how much fluid to consume, how much sodium to replace and how many calories you needed to get you to the finish as fast as possible, in just the right amounts to avoid any stomach issues, annoying muscle cramping or early onset fatigue.
- Do you know your calorie expenditure per hour based on the intensity that you compete at?
- Do you know your sweat rate (how much fluid you lose) in varying temperatures at the intensity you compete at?
- Do you know the sodium concentration of your sweat?
Your unique requirements set you apart from everyone else and learning just what they are is key to realising your true potential.
Unfortunately there is no one size fits all nutrition strategy that is going to suit every endurance athlete and given the duration and range of temperatures experienced, a sound understanding of your unique physiological makeup is paramount to having the knowledge to plan and practice what works best for you.
What follows is a guide to learning how to work out what your likely nutrition requirements are going to be and how they change based on intensity and the environmental conditions you are experiencing at the time. If you suffer stomach issues, muscle cramping or you feel you just haven’t got your nutrition strategy right, this information will help you solve these problems so you can enjoy your sport even more, regardless of the environmental conditions.
How many calories do I need to consume per hour?
To perform well at an endurance event you need to measure your effort and that means not going out too fast in the early stages and blowing up long before the finish line. The amount of calories you require per hour has nothing to do with how much you weigh, it is based on the intensity at which you compete. If you are properly prepared for these endurance events you should know the heart rate zone that best suits you based on your level of experience and fitness level. If not, you can go back over your data, if you have it recorded, and you should see a pattern forming showing average heart rate zones for your longer sessions. This data should also provide your calorie expenditure for those sessions specific to the intensity at which you compete at.
For example if your average heart rate is around 130 bpm and you burnt 2700 calories over 4 hours your calorie expenditure per hour is around 675 calories per hour.
If you don’t have this data available and you want to learn what your calorie expenditure is per hour you simply do a one-hour test holding the intensity, using heart rate, that you expect to compete at for the event. It’s important to do this testing relative to the event you are training for meaning wearing what you would wear and carry on race day. Mimicking race day as close as possible will highlight any issues that need to be rectified, such as chafing, balance and distribution of weight and comfort so you can just concentrate on getting to the finish.
Once you know your approximate calorie expenditure per hour you can begin to plan your likely calorie intake per hour. The goal for any endurance athlete when planning a nutrition strategy is to bridge the gap between how much you are expending and how much your stomach can tolerate/process. The challenge, more so for runners, is that the stomach is limited to how much it can tolerate/process per hour and there will always be a gap between how many calories you are expending per hour and how many calories your stomach is able to tolerate/process. The faster you go, the larger that gap becomes. While we are on the subject of stomach’s it highlights why I prefaced earlier that you are one of a kind simply because your stomach’s tolerance to a certain amount of calories per hour will vary between individuals, some athletes can consume a larger amount of calories than others regardless of their size.
To emphasize this even more the preference to flavour, texture, mouth-feel, ingredients and a whole range of other factors will vary wildly between individuals. Learn in training what works best for you long before you get to the start line.
Getting back to the initial question- how many calories do I need to consume per hour? Learn through training how many calories you are likely to expend per hour at the intensity you plan to compete at. Plan some key long sessions in your training schedule to practice consuming varying amounts and different types of foods and take note of how your stomach tolerated the amount and whether there were any signs of stomach distress. As a guide only, lets say your calorie expenditure is 650 calories per hour.
The goal here is to learn, through utilising specific training sessions, the maximum amount of calories your stomach can comfortably tolerate per hour over an extended period of time. You could practice consuming around 230 calories per hour to see how your stomach tolerates this amount over an extended period of time. It may be too much, or you may be able comfortably tolerate a greater amount. No one can advise you on how many calories to consume per hour, they would only be guessing. If you are able to tolerate a larger amount of calories, for example 290 calories per hour, comfortably without compromising the stomach this is the best you can do in bridging the gap between expenditure and intake.
Remember your stomach influences how well you will compete on the day and not compromising the stomach, but still managing to minimise percentage of loss is the key to a successful nutrition strategy.
Lets assume you want to complete the course in around 10 hours, based on 650 calories per hour, the total calorie expenditure will be around 6500 calories with an estimated intake of 230 calories per hour will provide around 2300 calories. If your stomach is able to tolerate/process the 290 calories per hour as suggested you have consumed 2900 calories over the duration of the event effectively allowing you to bridge the gap even better to your calorie expenditure. If you plan to be on course for longer obviously your calorie expenditure will be lower, lets say for example 300 calories per hour. If you aim to consume 230 – 290 calories per hour it’s simply going to be more than your stomach can tolerate so you will need to adjust accordingly and aim for a calorie intake of maybe around 120 calories per hour.
If you’re on course for around 15 hours, as mentioned, your calorie expenditure per hour is likely to be lower, say 300 calories per hour as a guide. Your total calorie expenditure will be around 4500 calories and your estimated calorie intake might be around 120 calories per hour for a total of around 1800 calories for the 15 hours. Hopefully these two examples give you an idea of what to think about when planning your calorie needs. As you can see there is and always will be a significant gap between calorie expenditure and the amount of calories your stomach is likely to be able to tolerate/process during activity.
There is a lot of talk about being fat adapted for these endurance events and the better conditioned you are the better the body is able to access these natural fat stores for fuel and help to bridge the gap that exists. However there’s only one way to improve your ability to access fat stores and that is getting out there and being consistent with your training.
The good news is once you learn the amount and type of calories that work best for you the amount you consume per hour will not change, regardless of the weather conditions. If your calorie expenditure is constant over the duration of the event, so to is your calorie intake. Whether it is 5 degrees or 35 degrees your calorie intake per hour remains the same. This is very important to remember because while your calorie intake remains the same your requirement for fluid will change throughout the event based on the environmental conditions you are experiencing at the time.
The weather conditions at the time will influence how much fluid you will need to consume per hour. Just this single piece of information should trigger fresh thinking when planning your hydration strategy over an extended period of time.
How much do I need to drink?
Sports nutrition is not a science and this statement could not be more relevant when determining how much fluid an athlete will need to consume during activity, as there are so many variables to consider. The first and most obvious variable is how much sweat you lose per hour and how this sweat rate changes as your intensity and the environmental conditions change.
The time to complete an event will generally be considerably slower when the temperatures are hot/humid and the reason for this is that sweat rates and the accumulative loss of sodium are greater. Your stomach has limits and regardless of how much sweat you are losing you can only consume as much as your stomach can tolerate/process. In hotter conditions the gap between how much sweat and sodium you lose and how much your stomach can tolerate increases and sweat loss (blood volume loss) and sodium loss have the biggest impact on how you function.
Depending on your unique physiological makeup some athletes will naturally have a low sweat rate and low sodium concentration in their sweat and their ability to perform well in hot conditions is due to the fact that they are able to bridge the gap more effectively between losses and their stomach’s tolerance, better than athletes with a higher sweat rate and accumulative loss of sodium. So if you love the heat then that is probably why, but if you tend to struggle in cooler conditions then read on. For those of you who don’t care much for the heat you either have a high sweat rate, high sodium concentration in your sweat or both.
The good news for those athletes who tend to struggle in the heat you can improve your performance in the heat and separating your calories from your hydration is the answer. Those of you with low sweat rates who tend to experience stomach issues in cold conditions separating your calories from your hydration is also the answer.
Sweat loss can vary considerably between individuals in the same conditions from 600 ml per hour up to 2.9 litres per hour. The next variable is the amount of sodium that you lose in sweat and this ranges massively between individuals from as low as 300 mg of sodium per 1 litre of sweat up to 2300 mg of sodium per 1 litre of sweat. As your sweat loss changes, based on the environmental conditions at the time, it alters the accumulative loss of sodium per hour.
Some of you won’t lose as much sodium as others and some of you will lose a huge amount of sodium, so your intake will vary dramatically. If you are confused about what your hydration needs are you can blame all these so called sports nutrition companies who promote these one size fits all powdered drinks that tell you it can provide everything you need in one convenient bottle. They treat every athlete as if they are all exactly the same and that the temperature never changes.
For some of you, certainly not everyone, a one size fits all powdered sports drink might just do the job in certain temperatures suited to you, meaning the volume of fluid you are consuming, the amount of calories and sodium your are accessing is at the right amounts to sufficiently replace what you are losing and not compromise the stomach. If the temperature stays the same you could justify using this one size fits all solution for the entirety of the event. But as we all know the temperature will change, sometimes dramatically, during an endurance event. This is when the powdered one size fits all sports drinks lets you down because it doesn’t allow the athlete the ability to adapt to changing weather conditions.
The fact of the matter is your hydration needs will change throughout the event and the changing environmental conditions will dictate how much fluid you should be consuming. Relying on calories in your drink locks you into a set volume of fluid and if you have experienced stomach issues in the past this could well be the reason.
A sound hydration strategy is built around having an understanding of what your likely sweat losses are in varying weather conditions and then learning the amount of fluid that you need to consume per hour without compromising the stomach. For endurance athletes it’s very possible you could be experiencing a range of temperatures from as low as 0 degrees on a mountain early morning, to as high as 35 degrees during the day.
Given the change in temperatures you are likely to experience, learning what your likely sweat rate is in varying conditions is an excellent way to plan and adjust your fluid intake according to the conditions you are experiencing at the time. Having this knowledge may also explain why sometimes you may have experienced stomach issues in the past.
This is common, especially in cooler conditions, if you are drinking a volume of fluid beyond what you require at the time because you are trying to access the calories in your drink. If it’s cool and you’re not sweating much, you don’t have to drink much. You need to adjust the volume of fluid you are consuming according to the environmental conditions at the time. Being mindful that your calorie intake per hour remains constant.
It’s quite simple to learn your approximate sweat loss per hour and you can do this at the same time you are testing your calorie expenditure. You want to mimic race day as close as possible so you may have to perform this sweat testing a few times at different temperatures. If it’s raining when you do the test take note of this so you can look back over your notes and see what your sweat rate was at a certain temperature in the rain and see if it’s different to when it’s the same temperature without rain.
If you ever experience an event where it is likely to rain, you will have information to draw on and plan accordingly. Make sure you are wearing and carrying all the equipment that you would be during the event, this includes any fluids, mandatory safety equipment, etc..
- Weigh yourself on a digital scale, nude, holding the bottle(s) of fluid that you will be consuming. If you intend on filling up bottles along the way calculate the weight and add this to your pre weight. Record the weight. (If you need to go to the toilet, do so before pre weight).
- Make sure you have a device that measures heart rate and calorie expenditure. Ensure that all your essential data has been entered correctly to give an approximate reading.
- Record the temperature and humidity during the test period.
- By using heart rate, run or ride for one hour at the intensity you would run or ride at on race day using average heart rate zone. If you intend on a run/walk strategy for the event use this same strategy for the test.
- Once you have finished, remove all your sweat soaked kit, dry yourself down and weigh yourself nude holding the same bottle(s). You may have some fluid left in the bottles, which needs to be recorded to provide a net weight loss. Record your weight.
- Calculate the difference between your pre and post weights. The weight differential is an approximation of your sweat loss per hour.
- Perform this same test in varying temperatures similar to what you may experience on race day to learn how your sweat rate changes based on the environmental conditions. Be sure to maintain a similar intensity for each test.
As you build an understanding of what your likely sweat rate/loss is per hour in varying temperatures you can practice the volume of fluid you need to consume per hour to ensure you’re not drinking too much to compromise the stomach in cool to cold conditions, but drinking enough in warmer conditions to minimise percentage of loss.
As mentioned throughout this article there are many differences that dictate what will work best for you. The amount of sodium you lose in sweat is another important consideration when planning a hydration strategy and unfortunately there’s no one size fits all amount.
The fact is you can’t plan your hydration strategy until the day before (sometimes even the morning) of the event once you have an understanding of what the likely temperatures are going to be. This is why it’s important to learn what your likely losses are going to be in varying temperatures because your fluid intake will change as the weather conditions change. Separating your calories from your hydration allows you to alter the volume of fluid you consume based on your individual needs and the changing temperatures you will encounter during an endurance event.
As a guide only, lets assume your sweat rate per hour in temperatures around 6 degrees might be 800ml per hour, your stomach may only be able to tolerate/process 200 – 300 ml of fluid per hour. On the flip side your sweat rate per hour in temperatures around 21 degrees might be 1.4 litres per hour, your stomach may only be able to tolerate/process around 750 ml per hour. In warmer conditions around 32 degrees your sweat rate might be 2.1 litres per hour, you will need to learn the maximum amount of fluid your stomach can tolerate to minimise percentage of loss, this might be as much as 1.2 litres per hour.
There is a limit to how much fluid your stomach can tolerate comfortably per hour. If you are a heavy sweater you will need to learn what this amount is, especially for events where it’s going to be warm to hot. Remembering as sweat rates increase in warmer conditions so to does your accumulative loss of sodium, which needs to be addressed as well. Learn what you lose in varying temperatures and then learn what your stomach can tolerate based on those temperatures.
Relying on calories in your drink does not allow you to make changes along the way and these one size fits all formula’s treats us as if we are all exactly the same and weather conditions never change.
Darryl Griffiths has been working with athletes for the past 20 years using common sense strategies to assist athletes learn how to maximize their performance by teaching them how to plan a nutrition strategy based on their own needs and how to adapt that strategy to changing environmental conditions. If you suffer from stomach issues and/or muscle cramping or early onset fatigue you no longer have to as Darryl has been solving these issues for many years.
There is a very good reason why Darryl has developed a sports nutrition range of products that separates calories from your hydration. It’s reason why when you combine his knowledge with the products that he has developed that so many athletes are now realising their true potential.
Check out Shotz Sports Nutrition and feel the difference when you separate your calories from your hydration.
To learn the sodium concentration of your sweat there is a sweat test kit you can purchase online, it’s easy to use and provides information about your unique requirements. Particularly important for those of you who tend to suffer in the heat. To learn more about planning a nutrition strategy for your individual needs don’t forget to read Sweat. Think. Go Faster - go to www.thinkgofaster.com