It is assumed that carbohydrates do not bring large profits in the first hour of endurance training, probably because the glycogen resources are not significantly impoverished then.In turn, there are reports on the benefits of carbohydrates even during less than one hour of strength training.
In general, systematic reviews of scientific studies indicate that carbohydrates bring the greatest benefit when used in a specific way.
The scientists took into account experimental studies, including those related to efficiency, continuous work of moderate or high intensity lasting longer than 60 minutes, carbohydrate intake (excluding rinsing with the liquid with carbohydrates of the mouth, because there are also such experiments).
30 studies were identified with 76 women and 505 men. Results and conclusions in 13 out of 17 studies the benefit of carbohydrates during the endurance exercise was demonstrated, the greatest benefit of carbohydrate administration is at work of more than 2 hours, although there is already strong evidence that supplementation is beneficial even for work lasting 90-120 minutes, too high supply of carbohydrates causes gastrointestinal discomfort without improving efficiency, endurance, carbohydrate blend has a positive effect on the performance when administered in an amount of ≥ 1.3 g per minute of work, in women, adolescents, older runners and people competing in conditions after a meal or carbohydrate loading, there may be other conditions that require further testing.
11 men were examined on three occasions during the run until exhaustion, with an interval of one week. It turned out that the water itself fed during the run with the intensity of 70% VO2 max to exhaustion allowed for 109.6 ± 9.6 minutes of run, carbohydrates (a solution containing 5.5% carbohydrates) allowed 124.5 ± 8.4 min, carbohydrates (a solution containing 6.9% carbohydrates) allowed 121.4 ± 9.4 min.
What kind of carbohydrates before, during and after training?
Before an isotonic or slightly hypotonic drink – 4-6% carbohydrates, 0.5-0.7 g of sodium per liter of drink (that is, 40 to 60 g carbohydrates in a liter, 4-6 g carbohydrates per 100 ml).
In the course of an isotonic drink – 6 to 9% carbohydrates, 0.5-0.7 g sodium per liter + additional amounts of sodium, if the work lasts over an hour or the effort is in unfavorable surroundings such as high temperature (that is 60 to 90 g carbohydrates per liter) .
After the hypertonic drink – 9-10% carbohydrates, 1 – 1.5 g sodium per liter drink (that is 90 to 100 g carbohydrates per liter).
How many carbs to give, what and when?
According to current recommendations for exercises lasting from 1 to 2.5 h, it is recommended to consume from 30 to 60 g of carbohydrates per hour, during work lasting 2-3 h, athletes should consume 60 g of carbohydrates per hour (~ 1.0-1.1 g / min), to maintain the maximum degree of carbohydrates oxidation (eg cycling, long-distance running, triathlon, multi-hour marches, etc.), better trained athletes of endurance disciplines can utilize up to 90 g of carbohydrates per hour (~ 1.5-1.8 g / min).A mixture of, for example, 1.2 g of glucose + 0.6 g of fructose per minute of work can be used, currently according to research, fructose returns to favor,
Interestingly, small amounts of carbohydrates can have an effect on improving performance even during short-term operation (45-60 minutes), with higher intensity (greater than 75% of peak oxygen absorption).This is surprising, the amount of muscle glycogen is not a barrier to work for 60 min, because the carbohydrate resources in the muscles are fully sufficient.Most likely, during short-term work, the impact of carbohydrates is recorded in the central nervous system.
It seems that to maximize performance, for example, running, carbohydrates (eg maltodextrin, glucose, carbo, vitargo, vextrago, etc.) can be given after 1 hour of work, although there are different recommendations in this matter.
You can read also: Carbohydrates – training support