Use of Carbohydrates in high intensity sports
The Carbohydrates are essential nutrients in the diet of exercisers, amateur and professional athletes, as they generate energy for maintenance and intensity throughout training.
The energy demand in prolonged training is made available through the breakdown of carbohydrates during exercise.
During moderate-intensity, long-duration exercise, fatigue may occur due to the use of muscle and liver glycogen.
The longer the training, the greater the use of glycogen for energy maintenance.
The evolution of carbohydrate use
Over the past twenty years, sports nutrition has evolved through studies in animals and humans, demonstrating the importance of pre-exercise nutrition and carbohydrate intake throughout the day—before, during, and after training. Following carbohydrate ingestion and the process of digestion and absorption, two important substrates are formed for use during training: muscle and liver glycogen.
Liver glycogen, or hepatic glycogen, has the main objective of being the immediate source of glucose to maintain blood glucose levels during training.
This stock, however, is limited. Around 40 to 60 minutes after the start of activity, these stores that maintain blood glucose levels are being depleted, and therefore, further glucose replacement through supplementation is necessary.
If carbohydrate supplementation is not carried out, another metabolic pathway for the production of blood glucose is activated: gluconeogenesis.
Gluconeogenesis produces glucose from three sources: lactate, glycerol, and amino acids. Lactate is produced through energy metabolism and transported to the liver (Cori cycle), where it is converted into glucose and released into the bloodstream.
Lipolysis, that is, the breakdown of body fat from the oxidation of triacylglycerols, releases glycerol into the bloodstream, which in the liver is transformed into glucose and helps to maintain blood glucose levels.
Amino acids, however, are available through the breakdown of muscle protein for glucose formation. This mechanism causes muscle mass to be used as an energy source during prolonged training. To prevent this from happening, it is essential to maintain carbohydrate supplementation throughout the entire workout, especially those lasting longer than 1 hour and 30 minutes.
Just as liver glycogen is important for maintaining energy during workouts, muscle glycogen is essential for maintaining the intensity of your training.
Muscle is a selfish tissue. The substrates stored within it are used solely for energy maintenance, and these reserves are limited. After the complete depletion of muscle glycogen, supplementation is important to maintain this energy supply to the muscles, and Xtratus was created for this purpose.
According to Jeukendrup, carbohydrate intake during longer workouts increases capacity and performance by reducing the cost of oxygen production.
The energy produced through carbohydrate metabolism is greater due to the availability of substrates and simpler due to its metabolic pathways compared to fat substrates. The energy yield from carbohydrates, in terms of oxygen volume, is therefore greater and easier for the body to utilize than when compared to fat substrates.
Another key role of the The importance of carbohydrates during periods of high-volume training is that these nutrients are important vehicles for the absorption of micronutrients and electrolytes.