Tiredness or fatigue is very common in all athletes who exercise regularly, but why does it happen?
In sporting terms, fatigue is akin to tiredness and is directly linked to a drop in physical performance. This state is reached for a variety of reasons, but in most cases it has four causes.
Causes of training fatigue
The four main causes of sports fatigue are:
- Lack of energy. This is the most common cause of fatigue, resulting from a lack of fuel in the body. Your body, especially your muscles, needs to have high glycogen stores to perform at their best. Therefore, when your levels of glycogen are low, you lack energy and muscle fatigue sets in.
To prevent this it is important to consume carbohydrates before long training sessions, around 60 minutes beforehand. This will top up your glycogen stores and help you to keep performing at your best throughout the workout.
- Excess lactate. This type of fatigue has more to do with the intensity of the training than its duration. When you subject your body to heavy physical exertion, you alter your body’s needs, as you produce a large amount of lactate that you are unable to get rid of. Combined with your body’s increased production of ATP (adenosine triphosphate) to meet the energy demands of your muscles, this excess lactate raises your body’s physiological pH. This leads to muscle soreness and a drastic and sudden decrease in your physical performance.
To prevent this type of fatigue, it is vital not to let your high-intensity training sessions last for too long.
- Dehydration. A lack of hydration is another of the most common causes of fatigue. Sweating causes you to lose water and mineral salts, and if you do not replenish the lost fluids, your amounts of nutrientsand blood are reduced, so your muscles do not receive the oxygen and fuel they need to contract. This leads to the dreaded muscle cramps.
To avoid this, it is important to stay properly hydrated and, for prolonged physical exercise, to provide your body with mineral salts. You can do this by having an isotonic drink or by adding 3-5 g of table salt to a litre of water and drinking it during training.
- Overheating. Your body regulates its temperature by sweating, but when it is not able to dissipate all the heat you generate during exercise, your body temperature rises. If this is combined with a hot, humid and poorly ventilated environment, your body reaches 38 or 39 degrees during training. Above this temperature, your performance drops sharply due to your body’s self-protection. This type of fatigue is closely linked to hydration, which is essential for the body to be able to regulate its temperature effectively.
Therefore, to avoid tiredness it is important to hydrate yourself properly and avoid the hottest times of the day, especially during the summer.