Question

A sports beverage contains 15 grams of carbohydrate in 8 ounces. How many ounces of this beverage should an athlete participating in recreational cycling lasting more than 2 hours consume per hour to provide the maximum recommended grams of carbohydrate per hour for recreational cycling (if no other carbohydrate source is consumed)? Explain how you calculated your answer.

Would you recommend carbohydrate loading for a short distance runner during the week before a track meet? Why or why not?

(Both are short answer)

Answer 1

1. Recreational cycling has a recommended carbohydrate intake of 30-60g/h. This is because the maximum amount of glucose that can be absorbed in GI tract if 60g/h. Hence, for recreational cycling, maximum carbohydrate intake should be 60g/h.

There are 15 carbohydrates in 8 ounce of the sports beverage. Hence to obtain 60g of carbohydrate in 1 hour, the person should take 28 ounces

15g= 8 ounces

60g= ? (A)

A= 60g/15g X 8 ounces= 4 X 8 ounces= 24 ounces

The athlete should consume 24 ounces of this beverage per hour.

2. Carbohydrate loading diet is used by endurance athletes such as marathon runners, swimmers or cyclist for a week before the actual exercise/event. This diet increases the amount of fuel storage in the muscle. Food contains starch, which is broken down to glucose in GI tract. Glucose is used by muscle during exercise to provide ATP. Excess glucose is also stored in liver and muscle as glycogen, which can then be used when required. Endurance athletes exercise for longer duration or their muscular activity is quite high. Any exercise for more than 90 minutes will deplete the muscle of stored glycogen, allowing accumulation of lactic acid. Carbohydrate loading allows more glycogen to be stored in the muscle, which can then be broken down to produce ATP. This will allow muscular activity for longer duration.

Short distance running includes running a 5K or 10K. Short distance running is only for a maximum time of 60 minutes (10K race averages at 57 minutes). Our body’s glycogen stores are sufficient to provide fuel/ ATP for 90 minutes. Further, carbohydrate loading does not include the extra energy food such as drinks, gels, or bars, fruit, or candies that are consumed to maintain carbohydrate levels of 30-60 g/h. This carbohydrate intake, which is not included in carbohydrate loading diet, will provide sufficient glucose for the short distance runners. Hence, carbohydrate loading diet is not recommended for short distance runners. The extra glycogen provided by the carbohydrate loading diet is not required by these short distance runners.