High Glycemic Sports Drinks & Beverages Impairs Sports Performance

High Blood Glucose is a Detriment to Athletes
Low Glycemic Index Beverages Improves Recovery from Prolonged Exercise

The Glycemic Index of the carbohydrates consumed in a sports drink or beverage determines metabolic response during exercise. So, choosing the right sports drink/beverage has a profound on sports performance.

High Glycemic Carbs Result in
Reduced Exercise Capacity

In a clinical study of 1000 athletes, elevated blood sugar levels result in reduced exercise capacity and reduced sports performance. Differences in clinical characteristics, exercise hemodynamics, perfusion imaging, and univariate as well as multivariate predictors of exercise capacity were determined(1).

Maximum oxygen consumption (VO2max/maximum oxygen consumption) and maximal watts were also measured.

The trial results showed that subjects with impaired fasting glucose or elevated blood glucose levels (126 mg/dl), experience lower VO2max and lower peak watts.

Imbalanced blood glucose levels are triggered by drinking High Glycemic sports drinks and beverages. This includes beverages containing High Glycemic carbohydrates, such as sucrose, and/or High Fructose Corn Syrup, Glucose, Agave, and/or Maltodextrins, as well as beverages that do not contain any carbohydrates or calories (High Cephalic), such as diet sodas, and sports drinks that claim -0- calories/carbs.

High Glycemic and High Cephalic beverages can also cause Reactive Hypoglycemia (low blood sugar), which impairs sports performance.

Consuming a High Glycemic or High Cephalic index beverage less than an hour prior to an athletic event can cause hypoglycemia at the start of the event, which drastically reduces sports performance and endurance.

Low Glycemic Index Beverages Improves Recovery from Prolonged Exercise

Low Glycemic Time-To-Exhaustion
Benefits Evidenced in Endurance Capacity

The Low Glycemic Index of a sports drink or beverage determines endurance capacity and time-to-exhaustion in active humans.

Subjects running for 90 minutes at 70% VO2max ingested Low Glycemic Index carbohydrates (8g CHO/kg body mass) vs High Glycemic Index carbohydrates.

Time-to-exhaustion during was longer in the Low Glycemic Index trial (108.9 +/- 7.4 min) than in the HGI trial (96.9 +/- 4.8 min).

Fat-oxidation (fat-burning) rates and free fatty acid concentrations were higher in the Low Glycemic Index trial than the High Glycemic Index trial.

Increased endurance capacity is a primary consequence of increased fat-oxidation following ingestion of a Low Glycemic sports drink/beverage.

Sports drinks and beverages containing Low Glycemic Index carbohydrates with a Low Glycemic Index (GI) maintain balanced and sustained blood glucose release and fat-oxidation, which spares muscle glycogen. The lower the Glycemic Index of the drink, the better blood glucose is sustained. In pre-event fueling, this is essential.


The vast majority of sports drinks and functional beverages on the market are high glycemic
High glycemic sports drinks overly-elevate blood glucose levels and reduce endurance capacity and fat-oxidation
Exercise capacity is tied to blood glucose levels
Elevated blood glucose levels impairs sports performance
Reduced sports performance is directly tied to ingestion of High Glycemic sports drinks and beverages

Copyright © 2008 Human Sports Performance® (HSP)

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