Carbohydrate gels are widely used in endurance sports because they act directly on the physiological mechanisms responsible for energy production during prolonged exercise. Their effectiveness is related to energy metabolism, intestinal absorption, and the maintenance of blood glucose levels throughout exertion.
Understanding these processes helps to understand why carbohydrate intake during exercise influences physical and cognitive performance.
Carbohydrates as an energy source in endurance sports.
In moderate to high-intensity exercise, carbohydrates are the most efficient substrate for energy production. They allow for a faster generation of ATP, the molecule that sustains muscle contraction, compared to fat oxidation.
During endurance exercise, carbohydrate availability is directly associated with the ability to maintain pace, power, and concentration throughout the exercise.
Muscle glycogen and blood glucose
The body stores carbohydrates primarily in the form of muscle and liver glycogen. These reserves are limited and progressively decrease during prolonged exercise.
Carbohydrate intake during exercise helps maintain stable blood glucose levels and reduces exclusive reliance on muscle glycogen, promoting continued energy production.
Intestinal absorption during exercise
During exercise, blood flow is primarily directed to the active muscles and to the control of body temperature. Even so, the intestine retains the ability to absorb carbohydrates when they are ingested in appropriate forms.
Carbohydrate gels utilize easily digestible sources, which facilitates absorption and the availability of energy during prolonged exertion.
Intestinal transporters and multiple carbohydrate sources
Carbohydrate absorption occurs through specific transporters in the intestine. Glucose and maltodextrin primarily utilize the SGLT1 transporter, while fructose utilizes GLUT5.
Combining different carbohydrate sources allows for the simultaneous use of these transporters, increasing the total amount of carbohydrate absorbed during exercise.
The role of palatinose in carbohydrate gels
Palatinose, also known as isomaltulose, is a carbohydrate that is digested and absorbed more slowly compared to rapidly absorbed carbohydrates. This characteristic results in a more gradual and stable glycemic response.
In carbohydrate gels, the presence of palatinose contributes to a more sustained energy supply throughout exercise, which can be especially relevant in prolonged efforts where blood glucose stability is an important factor for performance.
Carbohydrate oxidation and performance maintenance
After intestinal absorption, ingested carbohydrates can be rapidly utilized by working muscles. Ingestion during exercise increases the oxidation of carbohydrates from food and helps preserve some of the body's internal reserves.
This mechanism is associated with a reduced feeling of fatigue and the maintenance of physical and mental performance in endurance events.
What science shows
Scientific evidence indicates that carbohydrate intake during prolonged exercise improves energy availability, sustains energy production, and contributes to maintaining performance throughout the effort.
Carbohydrate gels represent a practical way to apply these physiological principles to endurance training, respecting the limits of the digestive system and the metabolic demands of exercise.
Scientific reference:
Notbohm HL, Feuerbacher JF, Papendorf F, et al.
Metabolic, hormonal and performance effects of isomaltulose ingestion before prolonged aerobic exercise.
Journal of the International Society of Sports Nutrition, 2021.
