Hypoglycemia in Sports: Reactive hypoglycemia is a disorder that can cause dizziness, which is common in athletes. Discover what it is about, when it appears and how to avoid it while practicing a sport.
The reactive hypoglycemia occurs by rapid elevation of blood glucose due to sugar intake in high concentrations, immediately before starting the exercise. The muscular contraction next to the mobilization of the muscular glycogen reserves causes that the glucose that circulates in the blood is captured quickly.
The GI or Glycemic Index is a value that is used to measure how quickly a food can raise glucose, that is, the level of blood sugar (the index can be high, medium or low):
Values greater than 70 are considered a high glycemic index.
Between 69-55 are considered glycemic index medium.
Least 54 is considered glycemic index low.
Gels, jellybeans, some sports bars, honey … are examples of foods with high GI. If we take foods or supplements with a high glycemic index, just before the competition, such as a gel, the release of insulin is stimulated, the combined action of insulin and the action of exercise itself significantly reduces the glycemia (blood glucose). So reactive hypoglycemia could appear.
Taking a gel before the competition will not necessarily produce reactive glycemia. There are different situations in which taking a sports gel can be beneficial and others in which you can not. In fact, not all gels or sports supplements are the same. Absorption will vary greatly depending on the sugars they carry as ingredients. If the sugars are rapidly absorbed , that is to say that their ingredients contain glucose, sucrose, dextrose … or if they are slow absorption (fructose, palatinose …) hypoglycemia may or may not occur, because glucose has an IG of 100 and for, On the contrary, fructose has a GI of 20, the difference is more than remarkable.
Let’s see two clear and differentiated examples :
Case 1: the athlete who has followed a correct food strategy before the sports test, with an adequate overload of carbohydrates, so that their glycogen stores are full. If you take a gel five minutes before the test, you may suffer reactive hypoglycemia, which is why it is not necessary at that time.
Case 2: Athlete who has not adequately performed the overload food strategy, so that their glycogen stores are not full. In addition, it has been heated intensively 15 minutes before the test. In this situation take a five minutes before the test would be justified, not having made an overload of glucose, and take 20 minutes intensely heating the blood glucose is already being used as a substrate, so ingest a gel at that time would provide more substrate. Insulin, having started physical activity decreases, so that glucose uptake will not be sudden and reactive hypoglycemia should not appear.
As a general rule, the more different sugars the gel or supplement has, the better the absorption speed improves as the sugar transporters do not saturate. However, each person is different, and although there are common tips, certain people are more prone to reactive hypoglycemia than others. The genetic factor also influences, so comparing athletes does not always work.
In conclusion, reactive hypoglycemia is easy to avoid if you know the situation and how to act, we can do it by following some tips:
It is recommended that you spend at least three hours between the intake of breakfast and the sports test, choosing carbohydrates that are not fast absorbed.
In the case of taking carbohydrates between one hour and a half and three hours before the test, it is recommended that they be more than 60 grams since it has been observed that more hypoglycemia occurs if less than 25 grams are taken than if they are taken more than 60 grams. Always of medium or low GI.
Do not take foods or high GI supplements just before the competition, in case they are taken, provided that previous intense heating has been initiated.
It is preferable to choose supplements with different types of sugars for more gradual absorption.
If you have any doubt, it is always advisable to consult a specialist.
What you should know…
Reactive hypoglycemia occurs because of the rapid rise in blood glucose (due to the intake of high concentrations of sugar), immediately before starting the exercise.
Not all gels or other sports supplements are the same because the absorption will depend a lot on the sugars they carry as ingredients.
Each person is different, and although there are common tips, certain people are more prone to reactive hypoglycemia than others, the genetic factor also influences.
Remember that hypoglycemia is different from hypotension.