Summer is right around the corner meaning warmer days and more training miles logged outdoors in the sunshine. Whether you love or hate training and racing in the heat, grabbing sports drinks to rehydrate and replenish is a must. As more people choose to add endurance racing to their list of hobbies, sports nutrition research has continued to grow. With more options on the market today it can feel overwhelming to figure out which sports drink is right for you and when you should be adding it into your training plan. Here we'll guide you on what to look for in a sports drink and when you'll see the benefits in your training and recovery.
The amount of carbs you need in a sports drink depends on the duration of exercise
While newer research shows that having some carbohydrates during shorter duration exercise, higher intensity workouts can improve exercise performance1, here we'll focus on how to tackle nutrition for longer duration training sessions and events. Below is the recommended amount and type of carbs per hour based on the duration of the exercise.
30-75 minutes: none to small amounts of carbs
1-2 hours: ~30g/hour, single or multiple carbs sources
2-3 hours: ~60g/hour, single or multiple carbs sources
Over 2.5 hours: ~90g/hour, only multiple carb sources
For athletes training at a low intensity, fewer carbohydrates are needed than suggested above due to lower rates of oxidation. For athletes training at a higher intensity, these numbers may be slightly higher. With an increase in exercise intensity, the active muscles become more dependent on carbs for energy.1
Carbohydrates
So what do we mean by single or multiple carb sources? All carbs are not created equal! Different types of carbohydrates consumed during exercise will be broken down and used at different rates. Using only one type of carbohydrate will limit the oxidation, or breakdown to energy at a certain point due to limited intestinal absorption.1 In other words, your body can only absorb so much during one session.
A recent review found that consuming multiple carbohydrate sources during exercise resulted in up to 75% higher oxidation rates than the intake of a single carb source. An example of this is glucose, which is known to use only one metabolic pathway.2
So what types of carbohydrate sources should be looking for on your sports fuel labels if you should be using a variety? Aim to combine simple carbs such as dextrose, fructose, sucrose, maltodextrin, and brown rice syrup. In a study looking at cyclists, a combination of fructose and maltodextrin resulted in significantly faster times and reduced GI distress.1 The multiple carbohydrate sources don't need to come from your sports drink alone! Add in gels, chews, and bars/solids low in fat, fiber, and protein to get that blend. Be wary of products with artificial sweeteners and sugar alcohols-- they may be advertised as ‘low calorie’ but can lead to GI distress. Also, since they are non-nutritive, they won’t provide any energy to fuel your workout! You will see them on the ingredient label listed as sucralose, saccharin, aspartame, acesulfame-K, sorbitol, mannitol, stevia, and xylitol.
Fluid
Along with getting in enough carbs, it is also important to be meeting your fluid needs during exercise. During exercise the body’s thirst mechanism is less sensitive than at rest, making an approach to fluids important especially when working at a higher intensity and warmer environments.3 As an athlete, you can choose a variety of products to fuel and these should be balanced with a plan that incorporates fluids. While solid foods and highly concentrated carbohydrates can be appealing fuel choice, they can reduce the absorption of fluids.1 Grabbing a sports drink is ideal to help to meet both fluid and carbohydrate needs while keeping blood sugars stable through your training session or race.
Sodium
When researching your sports drink options you should also pay attention to the sodium content. Sodium helps to promote fluid retention and possibly prevent hyponatremia, a low sodium concentration in the blood that can occur when an individual takes in too much water and not enough sodium. The ideal amount of sodium is 0.5-0.7 g/L of fluid for exercise lasting one hour or longer.4 Staying hydrated during exercise will also help performance, lower submaximal exercise heart rate, maintain plasma volume, and reduce heat stress, heat exhaustion, and possibly heat stroke.4
Training the gut
Just like you lace up your sneakers and log the miles to train for your event, it's also important for you to practice using sports drinks and fuels in your training. Having a plan is the first step but then you need to practice it to make sure it works! Research shows that athletes who consume carbs regularly or have a high carb intake daily may also have a higher ability to absorb it.1 What your training buddy uses as fuel may work for them, but not for you. Practicing your nutrition in workouts will help you to determine what products work for you.
The takeaway
Much like your day-to-day nutrition, sports fueling is not ‘one-size fits all’. What you need for your training and event will differ with intensity and duration. Choosing a sports drink that works for you while meeting carbohydrate, sodium, and fluid needs can be the game changer in hitting your training and racing goals.
References
1. Jeukendrup A. A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Med. 2014;44 Suppl 1(Suppl 1):S25–S33. doi:10.1007/s40279-014-0148-z
2. Jeukendrup A. Carbohydrate feeding during exercise. European Journal of Sport Science. 2008;8(2):77-86. http://search.ebscohost.com.ezproxy.neu.edu/login.aspx?direct=true&db=s3h&AN=31411750&site=ehost-live&scope=site. Accessed April 12, 2019.
3. Kenefick RW. Drinking Strategies: Planned Drinking Versus Drinking to Thirst. Sports Med. 2018;48(Suppl 1):31–37. doi:10.1007/s40279-017-0844-6
4. von Duvillard S, Braun W, Markofski M, Beneke R, Leithäuser R. Fluids and hydration in prolonged endurance performance. Nutrition. 2004;20(7-8):651-656. doi:10.1016/j.nut.2004.04.011