Cyclist hydration and the benefits of sports drinks

Water is life. And even more so during exercise. For the body to function properly during a bike ride, water alone may not be enough to compensate for deficits. This is where sports drinks come in. Here are our recommendations for fluid intake for cyclists.

By Jean-François Tatard – Photos: Frédéric Poirier, Pixabay.com, Kask

Your body contains a lot of water. True! But how much of this vital liquid does it represent exactly? And how is this water distributed in the human body? Why is it essential? How do its variations change when you ride?

Water accounts for an average of 60% of body weight. It is the main constituent of the human body. It is essential for life. We cannot live more than a few days without water. Water has many functions in the body: it is involved in the production of cells and body fluids; and it plays a role as a reaction medium, solvent, and reactant. It also transports nutrients and promotes the elimination of waste products from the body through urine. It is essential for controlling body temperature through sweat evaporation. To function optimally, it is not surprising that we need not to disturb this balance too much. Moreover, professional cycling teams take hydration very seriously, and during stage races or hard training blocks in training camps, staff weigh riders daily. They also regularly check urine.

The risks of dehydration

Whether you’re training, tackling a high-level competition, today is your D-Day, or you’re on a multi-day epic, if you don’t stay hydrated, you’ll compromise your performance! Indeed, if you unbalance this 60% proportion, you will significantly limit the benefits of your training. You will also take longer to recover. Performance will quickly decrease. Studies have shown that surprisingly small fluid losses can significantly affect your ability to ride. It is said that a 2% drop in body weight due to sweating (1.6 kg for an 80 kg cyclist) will significantly reduce performance, 4% will reduce your muscular work capacity, and at 5%, heat exhaustion can become a problem and your work capacity will drop by up to 30%. Beyond 7%: you will start to experience hallucinations, and at 10%, circulatory collapse, heatstroke, and even death become possibilities.

Why this drop in performance?

The physiological reasons for performance losses due to dehydration are:

1. A reduction in blood volume
2. A decrease in cutaneous blood flow
3. A decrease in the rate of perspiration
4. A decrease in heat dissipation
5. An increase in body temperature
6. An increase in the rate of muscle glycogen utilization
7. Decreased digestive function

How to monitor hydration?

Ultimately, it’s quite simple to monitor hydration. Two easy techniques to implement. Weigh yourself daily, and especially if you are already quite lean, significant and sudden weight drops probably suggest that you should increase your fluid intake. You can also monitor the color of your urine.

Daily drinking

Before considering what, when, and how much to drink on the bike, make sure you stay well hydrated continuously, even off the bike! This means you need to maintain optimal hydration levels when you go out for a ride. Monitor your hydration level off the bike and try to drink 2 to 3 liters of fluid per day, whether you’re riding or not. Fruit or vegetable juices, sports drinks, and water all count towards this goal, but not sodas or drinks loaded with alcohol, tea, coffee, and sugar.
If you monitor and control your hydration day by day, it should not be necessary to drink excessively the day before or in the hours leading up to a bike ride. If you drink excessive amounts in a desperate hope to catch up on your hydration, you will only succeed in guaranteeing early and numerous pee breaks. In the two hours before a long ride, a training session, or a difficult race, sip 500 to 750 ml of isotonic sports drink to ensure optimal hydration and fully stocked energy reserves.

On the bike

The best way to estimate how much fluid you need is to do a 60-minute sweat test. After hydrating well throughout the day, weigh yourself naked and record your weight. Go out and ride at your normal training or race intensity for 60 minutes and do not drink during the ride. As soon as you get home, undress, wipe any sweat from your skin, and weigh yourself again. The difference between the two weights in grams will correspond to the total fluid losses in milliliters.

Most cyclists will find that they will generally lose 500 to 1000 ml per hour.

Obviously, the results will vary depending on weather conditions and the intensity you put into your ride, and you may want to perform several tests to get a wider range. But this will still give you a good idea. Most cyclists will find that they will generally lose 500 to 1000 ml per hour. And especially if you are at the upper end of this range, it may not be practical or necessary to try to replace everything, but you should aim for a minimum of 75%.

How and what to drink on the bike

The key is to “don’t wait until you’re thirsty to drink“. Drink little and often, and from the beginning of your ride. Try to take 2 to 3 sips from your bottle every 10 to 15 minutes. Don’t forget your recovery drink at the end of your ride either. No matter how careful you’ve been with your hydration, especially on a hot day, you’re likely to be dehydrated, and in addition to providing protein and carbohydrates to kickstart your recovery, the fluids and electrolytes provided by a recovery drink are essential.

For rides under 60 minutes, plain water is fine, but for longer rides, I advise you to add electrolytes and carbohydrates. Why? Plain water won’t give you any energy, it can make you feel a bit bloated, and it will reduce your desire to drink before fluid losses have been replaced.

Electrolytes and carbohydrates

Electrolytes are salts that include sodium, potassium, calcium, and magnesium. They are lost in sweat. They are essential for normal cellular function and must be replaced. Most commercially available sports drinks have a good balance of electrolytes, and if you don’t want to drink for calories, effervescent carbohydrate-free electrolyte tablets are also available.

Remember that for a long ride, you will need to aim for 0.5 to 1 g of carbohydrates per kilogram of body weight per hour and you should also try to spread more than 2 to 3 micro-foods every 20 to 30 minutes. 500 ml of sports drink will give you about 36 g of carbohydrates, which, for an 80 kg cyclist requiring 40 to 80 g per hour, is a decent proportion and easy to assume in proportion to this energy need.The composition of sports drinks

Most sports drinks contain a mixture of simple sugars, such as glucose, fructose, and sucrose, which release their energy quickly, and also more complex carbohydrate polymers such as maltodextrin, which provide longer-term energy. As all sports drinks contain slightly different ingredients, it is important that you try them during training to find one that suits you perfectly for racing or a sportive. Don’t be too adventurous! Test the products well before D-Day! Beware: more than one person has already ruined their performance by venturing to try their new drink on race day.

Osmotic concentration

In somewhat barbaric names: have you ever heard of osmolarity? It’s a measurement! The measurement of the number of dissolved molecules in a solution, including electrolytes and carbohydrates. Blood typically has an osmolarity of about 300 mOsm/kg, and therefore a solution with a similar osmolarity is said to be isotonic, iso meaning the same. If the osmolarity is higher, it is hypertonic, and lower, hypotonic.

• Isotonic drinks

It is more relevant to use isotonic drinks for endurance sports, as they are established with a perfect balance between fluid replacement, carbohydrate and electrolyte supply, and stimulating your thirst. If you follow the mixing guidelines on most sports drinks, the 6-8% solution will generally be isotonic.

• Hypotonic drinks

Plain water, for example, is hypotonic. It will replace lost fluids very quickly but will not provide energy or important electrolytes. Moreover, as mentioned earlier, hypotonic drinks will often reduce your desire to drink more before you have replaced adequate fluids and will make you feel bloated.

• Hypertonic drinks

These are carbohydrate-loaded solutions that can be used for higher caloric intake. Many long-distance triathletes will have a bottle loaded with an extremely strong carbohydrate solution and use it in conjunction with plain water in their other bottle, for example. Also interesting for low-intensity winter rides where you won’t sweat much, stronger carbohydrate solutions can be experimented with. However, they will leave your stomach quite slowly and, as they can also cause gastric upset, they should first be carefully tried during training.

The consequences of too much fluid intake

Out of fear of running out or failing, you can sometimes drink too much water, and if you don’t also take adequate electrolytes alongside it, you will dilute and affect your body’s fluid balance. This can lead to bloating, decreased performance, and in extreme cases, hyponatremia, or even death. This is no joke! We have seen it in recent years during major marathons where runners, alerted by constant external reminders about the importance of staying hydrated, drank too much before the event and drank plain water at every aid station.

And remember, in addition to replacing lost fluid, you must also replace lost electrolytes.

Cramps

Many cyclists who suffer from cramps during a race or even training immediately link it to poor hydration and a lack of electrolyte intake. However, recent studies have indicated that this is not always the case. For such a common occurrence, you might be surprised to learn that the exact reason for cramps is still unknown.

Many people blame inadequate hydration or electrolyte levels, and while some studies have shown that consuming a 6% carbohydrate sports drink can help prevent them, other studies have failed to confirm this. Recent work with triathletes in Ironmans found no link. Some studies on people suffering from long-term cramps have shown that magnesium supplementation was more helpful. Another factor is a sudden increase in exercise intensity.

So, if you suddenly ride harder or longer than usual, you can expect cramps. However, exercise intensity cannot be the only factor as it does not explain nocturnal cramps, for example. Anecdotal evidence suggests that stretching can help relieve cramps and that regular stretching can help prevent cramps in muscles that are prone to them or have been previously injured. If you regularly suffer from cramps during your rides, we suggest an approach covering all bases:

1. Relax a little on your cadence and distance. You are doing too much.
2. Check your power, threshold, or heart rate,
3. Find your training zones and ride strictly within those ranges
4. If you go out for a long ride, this should mean that you will stay in the endurance zone most of the time.
5. Do not abruptly increase time, distance, or intensity.
6. Follow a structured training plan that builds progressively.
7. Continuously take fluids containing electrolytes throughout your ride. Even in cooler conditions, try to take 500 to 750 ml per hour.
8. At the same time, consider eating foods rich in magnesium and calcium and, if necessary, consider magnesium supplementation.

To conclude

Whether you are a professional cyclist or an amateur racer, hydration is a crucial factor influencing performance. Ultimately, drinking regularly and when you’re thirsty is not a detail. It’s a point you absolutely must not neglect! Remember, however, that excesses are just as harmful. So in the end, don’t try to replace the exact amount of water you’ve lost, or to compensate beyond the losses. Just remember to drink, before, after, and during exercise. Especially according to the needs you feel and depending on the degree of effort you are making… Cheers!

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