What to drink during training – water or isotonic drinks?

Many sports enthusiasts engage in regular physical activity to improve their fitness and athletic performance. However, it is worth bearing in mind that with prolonged physical activity, the human body loses more fluids and electrolytes, which affects performance during exercise and well-being during and after training.

Hydration levels also affect the nervous system, which is involved in the body's daily functioning. It is therefore important to remember to stay properly hydrated. But which is better to choose? Water or an isotonic drink?

1. What is the best way to hydrate? Water or isotonic drinks?
2. What are the risks of dehydration?
3. What to drink during strength training?
4. What to drink while running?
5. How much should you drink before, during and after training?

What is the best way to hydrate? Water or isotonic drinks?

When it comes to hydration, you first need to consider the type of physical activity a person does, its intensity and the duration of a single training session. These are factors that strongly determine hydration issues and influence how to emphasise them during or after training.

A very important factor determining the choice of water or isotonic drink is the duration of the training session mentioned above. People who engage in amateur physical activity, which usually lasts up to 1 hour or slightly longer, can safely choose medium-mineralised or highly mineralised water with an electrolyte tablet. The loss of fluids and electrolytes during physical activity lasting up to one hour is not so great that it is necessary to reach for an isotonic drink.

In addition, it is worth noting the lower energy losses for working muscles in the form of muscle glycogen, whose reserves are still at a high level during activity lasting about 1 hour. This means that hypoglycaemia, which can have a significant impact on the performance of a training session, does not yet occur. This may be indicated during periods of muscle mass building or weight maintenance.

Another situation is training or similar physical activity that is performed at a high intensity and lasts longer than 1 hour. This mainly refers to training sessions lasting approximately 1.5 hours or more. This situation mainly occurs among semi-professional or professional athletes preparing for important competitions or other sporting events. Their strenuous training sessions contribute to large losses of electrolytes such as sodium, potassium, calcium, chlorine and magnesium, which has a huge impact on athletic performance, even during training.

Therefore, for such individuals, an isotonic drink is the ideal solution. People who engage in physical activity, even on an amateur basis, but for a prolonged period of time, lasting around 1.5 hours or more, can also confidently reach for an isotonic drink. Their level of training means that high-intensity training also causes high losses of electrolytes and glucose, which is crucial in the process of supplying working muscles.

Comparing the two cases mentioned above, it can be clearly stated that the main factor determining the choice of a given drink is the duration of a given training session and the level of training of individual persons.

An isotonic drink is a selected mixture of the right amount of electrolytes and the right level of glucose per 100 g (usually 4-8 g of glucose per 100 g), which provides the right level of essential electrolytes to the intracellular space and fuel in the form of glucose for working muscles. It can therefore be said that an isotonic drink is a more effective type of drink for hydration, but its choice will be determined by the duration of the training session and the level of training of the individual.

What are the risks of dehydration?

During prolonged training sessions and insufficient fluid intake, dehydration may occur, which brings with it adverse symptoms and effects that have a huge impact on the functioning of the human body during and after training. The risks associated with dehydration include:

• decreased performance
• increased strain on the heart muscle
• impaired nervous system function
• cognitive impairment
• muscle cramps
• rapidly increasing fatigue
• nausea and vomiting
• digestive system disorders
• malaise

The first symptoms of dehydration can be seen even with a loss of just a few per cent of body weight in fluids. The first signs of dehydration are feeling unwell, impaired cognitive function and nausea. If training continues without rehydration despite nausea and concentration problems, it is not long before you feel worse and experience the full range of dehydration symptoms listed above.

What to drink during strength training?

There are various ways to stay hydrated during training sessions or physical exercise. Some people drink mineral water, others drink isotonic drinks. As above, a lot depends on your level of fitness, the intensity of your training and the duration of your training session. The longer we exercise at the gym, the more nutrients we lose through sweat or even breathing. Therefore, for strength training sessions lasting more than 1 hour, it is worth reaching for an isotonic drink, which will compensate for the loss of glucose levels as a result of muscle work.

People who exercise at the gym on a purely amateur level can safely drink mineral water with electrolytes, but only if their training session lasts about 1 hour, including warm-up, proper training and stretching.

What to drink while running?

When running, as with other physical activities such as exercise, a lot depends on the duration of the training session. Due to the fact that running training sessions significantly exceed 1 hour, it is worth reaching for an isotonic drink, which will prevent excessive loss of key electrolytes and glucose and will have a positive effect on maintaining the efficiency of your running training. Problems with nerve conduction, which often occur as a result of overheating and mild dehydration, can have a significant impact on running technique and performance. In addition, dehydration can increase the risk of injury, which is the worst possible scenario for an athlete who takes up running.

It is also worth bearing in mind that running, due to its nature, i.e. continuous movement of similar intensity, causes the sweat glands to work intensively, as they must regularly cool the runner's body to prevent overheating. In running, there is very little time for a break compared to strength training, where a series of exercises is followed by a break for the neuromuscular system to recover. This is not the case with running. There is a constant strain on the nervous and muscular systems, which requires a constant supply of electrolytes and glucose.

How much should you drink before, during and after training?

During training itself, but also before and after, it is very important to manage fluids properly. As a large amount of muscle tissue consists of water, body temperature rises during training, resulting in a natural, increased sweating process.

The amount of sweat produced depends on gender, body weight and fitness level. For example, during an hour-long training session, an average fit person can lose up to 1.5 litres of water through sweat. The more intense the training, the more water we lose. However, we do not only lose water, but also many electrolytes along with sweat, which contribute to maintaining the proper acid-base balance.

The average fluid requirement for an adult is about 1.5-2 litres per day, which of course includes coffee, tea, juices and water from food (fruit and vegetables contain the most). This is the absolute minimum that must be met to keep all vital organs and muscles hydrated.

In order for the body to be fit for training, it must be properly prepared. It is recommended to drink about 300 ml of water approximately 15 minutes before training. During training, you should also drink water, in smaller amounts but more frequently, so as not to cause stomach overflow, about 200 ml every 20-25 minutes.

Is water alone enough?

If the training is intense, the demand for water and electrolytes increases. Water alone cannot replenish all the deficiencies that we sweat out. It is worth considering consuming isotonic drinks during training, which, in addition to hydration, provide mineral salts, sodium and electrolytes. Many isotonic drinks, in addition to the above-mentioned elements, also contain a small percentage of carbohydrates, which can provide additional stimulation during training. An hour-long training session requires the body to be supplied with at least 1 litre of water. This is the minimum necessary for a quality workout.

The amount of fluids after training should depend on the amount of fluids lost in the form of body weight. A good way to do this is to weigh yourself before and after training. This can help you estimate how much water you need to drink after training. Another important indicator is the colour of your urine, which signals your level of hydration: the darker it is, the more dehydrated you are. Fluids should be replenished within 2 hours after training.

There are many types of water available in shops. Is all water the same? No, it is not. If we look at each label, we can see the difference in the proportion of minerals. Water contains cations (calcium, magnesium, potassium and sodium) and anions (bicarbonate and sulphate), each of which has different properties.

Low-mineralised water is not a good choice because it does not hydrate us optimally and is also devoid of electrolytes. During long training sessions, it is worth reaching for medium-mineralised water, which will optimally replenish water and electrolyte deficiencies, as well as mineral salts. Medium mineralised water contains approximately 500-1500 mg/l of minerals, and the magnesium and calcium it contains will help to meet your daily requirement for bioelements. This water also allows you to get rid of unnecessary metabolic products produced during training.

Sources:

• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4129840/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4993146/
• https://pubmed.ncbi.nlm.nih.gov/10410838/