Carbohydrates and the Endurance Athlete

Carbohydrates are key to athletic performance and are required to provide energy during exercise, and are stored primarily within the muscles and liver and are important to maintain blood glucose and replace muscle glycogen. They are central to an athlete’s diet, particularly on intense and heavy training days and improve performance by fuelling high-intensity efforts, reducing perceptions of fatigue, and enhancing cognitive drive. As you can see, carbohydrates are essential for athletes, as it’s the only macronutrient that can be broken down rapidly enough to provide energy during periods of high-intensity exercise.

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Generally speaking, carbohydrate intake ranges from 5-7 g/kg of body weight/day for general training needs and 7-10 g/kg of body weight/day for the increased needs of endurance athletes.

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Interestingly, studies have found that many athletes fail to consume enough carbohydrates to fully replenish muscle glycogen stores. This is something I see quite with new clients who approach me to carry out a nutritional assessment. I especially find this with both higher end runners and younger athletes more so.

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Depending on the sport or duration of a workout, it is recommended that athletes time their carb intake to enhance performance. Here are some general recommendations surrounding carb intake for athletes:

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Pre-workout - Try to consume complex carbohydrates 2–3 hours before exercise, and simple carbohydrates (energy gels, jelly beans) 30–60 minutes in advance.

During exercise - The amount of carbohydrates needed will vary depending on the length and type of workout.

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• 30-60 minutes: it is not necessary to ingest large amounts of carbohydrate.
• 1-2 hours: 30 - 60 g/h of carbohydrates to keep energy levels up.
• <2 hours: <120g/h of carbohydrates (Fructose + Glucose) to ensure we achieve optimal performance.
  
  

Post-workout - Often, the time available to recover between successive athletic competitions or training sessions is short. In such cases, rapid glycogen synthesis is even more important. Although muscle glycogen concentrations are unlikely to be completely restored to pre-exercise levels, all methods of carbohydrate supplementation that maximise glycogen restoration may benefit performance. Five factors have been recognised as potentially important in promoting restoration of muscle glycogen stores:

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• Timing of carbohydrate intake
• Rate of carbohydrate ingestion
• The type of carbohydrate ingested
• The ingestion of protein and carbohydrate after exercise
• The intake of caffeine

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Daily carbohydrate goals are dependent upon the type, intensity and duration of exercise and can often range from 3-12g/kg of body weight dependent on the five factors stated above.

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• 3-5 g/kg of body weight on light exercise days to.
• 8-12 g/kg of body weight on extreme exercise days.
  

• Average daily intake: Carb intake will vary depending on the intensity, duration, and frequency of exercise, but it's suggested that 6-10 g/kg/day can support daily energy output for endurance athletes

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In the next blog we'll look at Protein ingestion for athletes and breakdown what is important for endurance athletes.