How to fuel during exercise

We have learned here that our glycogen stores are very important for performance. Our next question is how do I fill up my glycogen stores so that I am ready for exercise? I.e., how can my energy intake prior to exercise influence my performance. In addition, it is especially important to replenish these glycogen stores with carbohydrate intake for improved recovery and future performance. As you have probably heard before, the timing of carbohydrate consumption is best immediately after exercise. When glycogen stores are depleted, the body begins to use other fuel sources like fat, but this can lead to fatigue and reduced performance. So, we need to have full stores of glycogen at the beginning of our training sessions and races to continue pushing the limits of our bodies and achieve maximal performance.

Let’s think about this more practically. What do we need to do to help our glycogen stores give us energy? (note: this is even more important for longer events and training days)

Goal 1 is to increase calorie intake (especially carbohydrates) and prepare the body. By not preparing yourself nutritionally and coming into the race depleted, it is almost like you are asking for trouble and declines in performance. For me personally, it is generally not easy for me to eat in the morning of the race (especially when I was younger and putting a lot of pressure on myself). For me, I do not follow a specific diet (you can if it helps), but I do best when I focus on simply getting food in. Food that tastes good to me. I fill up my glycogen stores by preparing and eating what is a healthy quantity and quality with something I want to eat, as eating is the most important. 

Goal 2 is to focus on recovery after each session or race. We already mentioned above that it is important to eat immediately after the session. I have also personally experienced that the more and better I take care of myself (eat and hydrate) during an intense session (especially during long efforts), the better I feel, and quicker recovery is for my body. 

Goal 3 is to improve hydration by focusing on increasing electrolyte consumption, being hydrated before exercise, staying hydrated during exercise, and replenishing hydration after exercise. This can include water as well as carbohydrate concentrations mixed with fluids (liquid calories), with attention to electrolytes including sodium/salt. Special awareness should come in consuming sufficient fluids during training and racing, while also paying close attention to the signals of the body in how it responds (more on that in a moment).

If we specifically look at racing for a moment, no matter what distance is planned, there are a few main things to consider for fueling. These are having a good, healthy (including carbohydrate rich) dinner the night before, along with an appropriate breakfast with carbohydrates and maybe some good coffee to fill up glycogen stores. From there, in your warm-up and preparations for the race to begin, you may consider taking a banana or gel to boost you into the race fuel (especially if you have done a considerable warm-up and can consume some nutrients prior to the race starting, be sure to give yourself 10-15 min of digestion time afterwards). The longer the race duration, the trickier this concept of adequately fueling your body might become. For example, in races 20-50+ km, you will need to consume some calories along the way with feeds or aid stations or nutrition you carry with you (aiming for 60-90 grams of carbohydrates per hour). Hydration is of the first importance, thinking to get some calories in there with carbohydrates and electrolytes is ideal. These distances will require you to have quick logistics and planning to consume while exercising (ideally on a flat or downhill section so you can focus on swallowing and have less demand of breathing). There start to be many things to think about regarding strategies. Hmm. Let’s take it a step further to consider races lasting several hours (50km +, maybe into some multiple day adventures). We start with similar strategies, eating well the night and morning before, but we must begin to secure glycogen in our bodies in the days leading up to the race. Think a couple/few days of boosting calories with healthy nutrients including carbohydrates. This is not an article focusing on carb-loading, but it is focused on emphasizing that we need good food prior to racing. This will help our bodies perform the best they can. So, back to the longer race strategies for fueling…you will likely consume a lot of fluids, ideally water but also liquid calories with carbohydrates, aiming for a 50/50 mix of glucose and fructose for stomach tolerance. As the duration increases it will become of greater importance to match salt in relation to your sweat ratio and how ‘salty you sweat’, you will start introducing solid foods (bars, real food) to bring in more calories, paying attention to fat and carbohydrates, you might work on some caffeine strategies in addition to increased calorie consumption for aid in lack of sleep situations. Ideally in these longer races it becomes 100+ grams of carbohydrates per hour – and really comes down to consuming as much as you can take (related to stomach, response of digestion, fluid carrying capacity, etc.). See the figure below to help you brainstorm about carbohydrate intake during exercise.

Let’s dive into some signals our bodies can give us about the response we have to the fuel we choose; it is about what kind and how often we fuel. This is a very individual process, what I am about to share is based on my own experiences and what I have heard from others. It is vital for you to do some trial and error in your own ‘experiments’ to figure out what tastes, works, and feels the best for your body. These can be questions about sugar, fluid volume, calorie content, protein intake, salt intake, etc. For example…what is too sugary (i.e., high concentrations of glucose, simple sugars)? What do I do to recover if my stomach feels too sugary (i.e., increase water intake, focus on other fuels until stomach settles, get some carbonated drink to help burp and get digestion moving again, try to take a break from complex fuels and stay simple until you try to ‘reset’)? What fluid volume can my body handle? What volume of fluids can I carry/do I need to carry to properly fuel my body (these questions depend on the distance/duration/sweat rate)? Can my system handle high calorie intake foods (high fat content foods, bars with lots of calories, what foods work best)? Can my body digest protein during competition (how does it make me feel?) If it does digest ok, this can be a great fuel strategy to spark recovery along the way. 

Another important area of consideration is around salt intake. Sodium is an important electrolyte as some of us lose a lot of salt through sweat. I am one of these salty sweaters…and one of my strategies is to experiment with salt tablets. I have struggled quite a lot in my days with cramping and have found that for me, taking in a greater amount of salt tends to help my muscles keep up with the higher demand (usually due to lots of incline/decline during long running events, where the demand on my muscles is very high). One of the best prevention strategies for cramping is adequate training and conditioning for the specific terrain/style of race. From there, some of the best cramp treatment strategies might include stretching, massage, reducing exercise intensity/pace, focusing on nutrition with adequate electrolytes and fluids. 

With all the differing responses to fuels that also depend on the frequency of consumption and combinations of fuel types, it is logical to say that practicing and training these fuel plans is important. Not only from the logistics of what, how to carry, when to take, but also from the response of the body and ability to absorb and digest these fuels. From there it is about figuring out how to respond when your body gives you a signal or when something happens that is not ideal (tummy turns and you can’t intake what you wanted due to sensations or reactions). Training to fuel during exercise is a skill that needs refining. I will send you on your way to experiment with different strategies and encourage you to pay attention to your body’s response for digestion and preferences as you try various fuels differing in glucose, fluid volume, salt, calorie content, and protein content. This takes time but this process to learn your body and responses will support you in all your athletic endeavors. Have fun playing with your nutrition!