Hypoglycaemia and exercise


When training or competing, you've almost certainly gotten dizzy or felt a sudden onset of fatigue. These are the symptoms of hypoglycaemia, which is caused when individuals with a poorly-balanced diet or a diet low in carbohydrates do intense exercise. How does hypoglycaemia work? How can you avoid it?


What is hypoglycaemia?

Athletes need about 1 gram or 5 millimoles of glucose per litre of blood. If your blood sugar level falls to between 0.8 and 0.6 g per litre, you will experience a rapid onset of hypoglycaemia. Hypoglycaemia can quickly lead to balance problems or cause you to lose consciousness if you do not quickly react to it (by slowing down or stopping altogether).

Marathon runners often begin to run low on glycogen starting in the 30th kilometre of the race. The so-called "marathon wall" involves violent muscle pain and is a sign of hypoglycaemia.


Causes and symptoms of hypoglycaemia

The main cause of hypoglycaemia is a lack of blood sugar usually caused by irregular or insufficient daily nutrition, too little or too much physical activity or intense stress. Symptoms of hypoglycaemia vary depending on the individual. From a medical perspective, three factors precisely condition hypoglycaemia:

- a sudden, unexpected decrease in energy leading to a variety of symptoms, including nervousness, shaking, hunger pangs, fatigue, vision problems, and more.

- blood sugar below 3. 5 millimoles per litre of blood

- dizziness which disappears after ingesting sugary substances (e.g. sugar cubes, candy, fruit juice. etc.)

Hypoglycaemia is harmless and rapidly diminishes after ingesting sugary foods. If it recurs, it is important to consult your doctor to determine the exact causes of the stages of hypoglycaemia.


How can you avoid it?

Eating a well-balanced diet over the course of the day, managing stress in a healthy way and gradually increasing your physical activities all help to significantly decrease hypoglycaemia.

Don't skip meals, and make sure to eat a healthy, well-balanced diet.

Eat three meals per day. Meals containing complex carbohydrates (eg pasta, rice, etc.) and fibre (fruits and vegetables) are essential for maintaining a high enough blood sugar level. Throughout the day, it is important to eat small snacks or light meals to stabilise your blood sugar levels.


Do physical activities

Doing physical activities helps the hormones that regulate blood sugar (insulin and glucagon) to work properly and helps to handle stress better. When you are exercising, remember to drink small sips of a high-carbohydrate drink or eat foods with lots of sugar in them (cereal bars, fruit jellies, etc.)


Preventing hypoglycaemia when running

To avoid hypoglycaemia while exercising, you should:

- eat complex carbohydrates (eg pasta, rice, potatoes, grains, etc.) well before setting out;- drink enough liquids during your run (either water or a high-carbohydrate beverage);

- eat solid foods which are packed with carbohydrates (eg fruit jellies, cereal bars, etc.) after your run; and

- modify your speed, especially in warm weather, and vary your pace to promote recovery.


Did you know?

Managing stress is one of the most important factors in preventing hypoglycaemia. Stress causes your body to use up large amounts of glucose. In fact, doctors have observed that cases of hypoglycaemia decrease significantly during the holidays. Good ways to avoid hypoglycaemia include relaxation techniques, physical activity (running, walking, swimming, etc.), relaxation and rest periods.


What should I do if I feel like my blood sugar is getting low?

As soon as you experience the first symptoms of hypoglycaemia (dizziness, fatigue, trembling, etc.), you should:

- immediately decrease your pace; and

- drink several sips of a drink containing 100 g/l of glucose.

Always remember to carry a few sugar cubes to reduce the effects of hypoglycaemia and replenish your energy.

Remember: Hypoglycaemia results from lower blood sugar after eating unbalanced meals, eating at different times from you normal mealtimes, and/or dealing with stress poorly. When you are exercising, symptoms such as nervousness, paleness, intense fatigue, and hunger pangs are signs of low blood sugar, but ingesting sugars will help you replenish your energy. In any case, you should consult a doctor, who will assess the exact causes of your condition. With a good lifestyle and a few sessions on the trail, you'll get off to a great start and stay in shape for many years to come!


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