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​The two primary causes of fatigue in endurance sports

The two primary causes of fatigue in endurance sports

What are the primary causes of fatigue in endurance sports?
What do you really need to pay attention to when running a marathon or partecipate a cycling race in order to prevent fatigue?
Which supplements are "indispensable"?

These are the questions that many athletes ask themselves before gearing up for a race.

These days, more than ever, athletes don't want to leave anything to chance, especially when gearing up for a race they’ve spent months training and making sacrifices for. It makes sense to want to make the most of it, without leaving anything to chance.

When it comes to competitions that last several hours and involve heavy caloric expenditure, food supplements are fundamental to complete events under the best conditions. This is a vital aspect for any athlete, and people who have already participated in competitions will certainly already be aware of the fact.

It is no coincidence that you’ll find refreshment stands at various cycling and running events. Indeed, participants consider them to be very important when assessing how well organized an event is or when making up their mind about whether to compete.

Often in fact, people leave comments in forums or have post-race conversations that go along the lines of: "there were so many refreshments available, it was great," "there was a good selection of refreshments for late arrivals, too," "refreshments were poor, only water was available and I had to fight off cramps because I was exhausted" or "there were no refreshments left for those arriving later, even though we paid the same price as people who arrived earlier," etc.

In short, nutrition and hydration are considered vital elements for all race participants, and rightly so!

Following the European Commission’s guidelines, the two primary causes of exercise fatigue are decreased carbohydrate reserves and dehydration as a result of the loss of water and electrolytes through sweat.

Athletes should therefore remember that:

  • Drinks containing carbohydrates (4-9%), e.g. glucose, maltodextrin, sucrose and electrolytes – and sodium in particular (0.05-0.1%) – improve performance during prolonged exercise.
  • Iso-hypotonic solutions (about 300 mOsm/kg of water) promote faster rehydration.
  • An athlete's normal diet should include about 310g of carbohydrates per day out of a total of 2,500 kcal/70 kg or 4.5g/kg.
  • The amount of carbohydrates eaten in the days (3-4) leading up to the race can reach up to 600g/day i.e. 9-10 g/kg.
  • In the 24 hours after exercising athletes need at least 75% (energy%) in the form of metabolisable carbohydrates with a high glycaemic index.

After intensely exercising, athletes should consume carbohydrates and proteins (e.g. 1g/kg of carbohydrates and 0.5g/kg of protein) within 30 minutes and a high-carbohydrate meal within two hours of exercising.

As previously mentioned, these tips should be applied to the day of the event as well as pre- and post-race.

Let’s take a look at a few "indispensable" energy supplements, which should always be in an athelete’s pocket before leaving for a race.

Athletes should always be equipped with mineral salts dissolved in water for good hydration, which can also be consumed at refreshment points (if present). They should also carry carbohydrates with them in the form of energetic gels that are easy to transport and rapidly absorbed or dissolved in a water bottle (maltodextrin).

Our recommended supplements

The products we recommend include:

Isodrink: mineral salts in soluble powder available in three different flavours.


· carbohydrates with a low glycaemic index (fructose) that don’t favour the onset of rebound hypoglycaemia (such as glucose or sucrose);

· complex natural carbohydrates (maltodextrin) with the best osmotic profile (= rapid hydration);

· lactic acid buffers such as bicarbonate, able to counteract the onset of fatigue and consequent muscle aches (cramps);

· antioxidant and anti-stress vitamin C;

· the osmolarity of isotonic solutions (305 mOsm/l equal to 30g/0.5 l water) – written on the label;

· sodium/potassium molar ratio in accordance with FAO/WHO recommendations for Oral Rehydration Solutions (ORS) (= 4.5)

· no artificial dyes, sweeteners or hydrogenated fats;

· maximum energy density, understood as caloric intake per isotonic dose (= maximum energy power).

Mineral MCKg: mineral salts in convenient lemon-flavoured chewable tablets.

Energen 30ml: energy gel in convenient single-dose sachets, available in five different flavours (including two new ones: cola and coffee).


· contain the main amino acids involved in cellular protein metabolism;

· are the fastest-moving natural energy carbohydrates;

· contain vitamin C, which provides protection from oxidative stress linked to fatigue;

· contain all salts required under stress;

· contain anti-fatigue nerve stimulants and lipotropic energy activators;

· do not contain gluten, lactose or fibre.

Maltovis: corn maltodextrin in a soluble powder with a neutral taste (free from flavourings).

​The two primary causes of fatigue in endurance sports
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