Water is essential for our body, so it is necessary to drink fluids and eat foods containing water every day. Exercise in hot weather raises body and core temperatures and also reduces body water content, so fluid intake is critical to maintain performance and prevent dehydration, which can cause serious problems [1, 2]. However, drinking too much plain water during training can negatively affect its performance [3, 4]. That’s where sports drinks come to the rescue!
What Are Electrolyte-Enhanced Waters?
Sports drinks, also known as electrolyte drinks/isotonic drinks are functional beverages that are an aqueous solution of the body’s electrolytes (calcium, magnesium, sodium, and potassium chlorides), often with added carbohydrates.
In addition to replenishing the loss of fluid lost by the body during physical activity (which ordinary water can handle), isotonic drinks help to replace the loss of minerals in the body that are lost during sweating. Moreover, glucose provides the body with fast fuel to get the job done.
The Need to Drink
When an athlete loses fluid, certain symptoms appear:
- losing 1% of your total weight will cause you to feel thirsty
- 2% – reduced stamina
- loss of 3% – decrease in strength
- 5% – decreased salivation, urination, increased heart rate, apathy, muscle weakness, nausea, and sometimes dizziness.
Dehydration causes significant loss of minerals and a state of electrolyte imbalance. This loss affects, first of all, the conduction of the nerve impulse into the cell and its response, and the aerobic power also decreases. Therefore, when composing isotonic drinks, glucose polymers and multivitamin complexes are used.
Sports Drinks’ Components
These are minerals dissolved in water that form salty gel-like shells around and inside cells.
These cells exchange electrical charges, react with other minerals and, most importantly, transmit nerve impulses, signaling the muscles to contract and relax. In addition, electrolytes regulate the fluid balance inside and outside the cells.
It is especially important to restore electrolyte balance in endurance workouts that last over 45 minutes. The density of an isotonic solution is approximately equal to the density of blood plasma, therefore, the necessary substances are quickly absorbed and effectively help maintain the water-salt balance.
Most isotonic drinks contain 4 to 10% sugar. This concentration of glucose promotes an increase in absorption into the blood, very close to the rate of absorption of water. An 8-10% solution is almost instantly absorbed, which significantly increases the functional capabilities of the body.
Sweet tonics, used during training or competition, improve the performance of an athlete, increase their endurance during prolonged exertion by supplying muscles with fast carbohydrates that help depleted glycogen stores.
Minerals, Salts, and Antioxidants
The main task of antioxidants is to maintain the oxygen balance in the blood. Antioxidants (most commonly carotenoids, flavonoids, and herbal extracts) reduce the effects of free radicals. These oxygen-containing molecular fragments actively grow during intense physical exertion and initiate cell destruction and death.
Vitamins and minerals in sports drinks perform hematopoietic (iron) and regulatory functions – synthesis of protein and connective tissue (zinc), stimulate the immune and nervous systems (magnesium, selenium), nourish muscle tissue, including the heart muscle (potassium, magnesium).
Are Sports Drinks Good for You?
- Isotonics have no contraindications, but diabetics should remember that sports drinks contain glucose, so you should consult your doctor before using them.
- Some beverages may cause discoloration of the tooth enamel.
- It is always worth reading the composition of the electrolyte drinks, making sure that there are no products in the composition to which you have an individual intolerance.
- Also, pay attention to the fact that electrolyte drinks may contain acidity regulators, dyes, preservatives, and sweeteners, which contradicts the idea of a “healthy” drink.
- It is necessary to pay attention to the dangers of consuming caffeine and weak alcoholic beverages, which stimulate the excretion of fluid in the urine.
In any of the options, isotonic is the ideal way to replenish all the losses during training: water, carbohydrates, trace elements, and vitamins.
Sports electrolyte-enhanced waters can be purchased ready-made or in the form of powders that are dissolved in water. Use fortified water as tonics, drink juices (because, in addition to water, they contain sugar and a low amount of vitamins and minerals, mineral water). All these are excellent sources of trace elements, salts that are lost with sweat. In addition, you can drink herbal infusions and decoctions, lemonades, and fruit drinks.
When to Drink
Isotonic sports drinks are taken 1-1.5 hours before training. If a hard workout is not expected, you can also drink degassed mineral water or fresh juices instead of tonics.
Athletes also drink such waters during training to compensate for the loss of macro- and microelements, and/or immediately after training – to restore the acid-base state and within 1-2 hours after completion of work to completely restore the water balance and replace the loss of vitamins and salts.
Studies About Sports Drinks
The relationship between involuntary muscle contraction and the amount of water you drink
Hoffman and Stuempfle  showed that overhydration is the main characteristic of symptomatic hyponatremia during a 161 km run. One of the symptoms of hyponatremia is muscle cramps, which are painful involuntary muscle contractions.
When muscle cramps occur during and/or after exercise, they are called exercise-associated muscle cramps (EAMCs).
It is possible that drinking large amounts of plain water dilutes sodium and other electrolytes in blood and extracellular fluid, increasing susceptibility to EAMC. [6-8].
The prevalence of EAMC among participants is 39% in marathons, 52% in rugby, 60% in cycling, and 68% in triathlon. Schwellnus et al.  reported that 20% of triathletes experienced muscle cramps one or more times during and/or within 6 hours of an Ironman triathlon race. The exact mechanisms underlying EAMC are unknown but are likely to be multifactorial. Giuriato et al.  reported that EAMC arises from an imbalance between the excitatory drive from muscle spindles and inhibitory drive from Golgi tendon organs to alpha motor neurons, and not due to dehydration or electrolyte deficiency. On the other hand, Maughan and Shirreffs  stated in a recent review paper that high ambient temperatures and high sweat loss with large amounts of plain water may be risk factors for EAMC.
Effect of Plain Water and Sports Drinks on EAMC
So a new study published this year looked at the effect of plain water on EAMC versus water containing electrolytes to see if there were any differences between these conditions. According to the conditions of the experiment, 10 people performed downhill skiing in the heat (35-36 ° C) for 40-60 minutes until their body weight decreased by 1.5-2% under two conditions. In the first case, the participants drank equal amounts of spring water, in the second, an oral rehydration solution containing sodium (1150 mg / l), potassium (780 mg / l), magnesium (24 mg / l), chloride (1770 mg / l), glucose (18,000 mg / l) and others (for example, phosphorus). The time difference between the two conditions was a week. The sensitivity of the gastrocnemius muscles to seizures was assessed by the threshold frequency of stimulation with electric current to induce seizures before, immediately after, and 30 and 65 min after the descent.
The threshold frequency of stimulation decreased from baseline when the participants drank plain water, meaning that it became easier to induce cramps in their calf muscles with an electric shock. And in the case when the participants drank the solution, the threshold frequency even increased from the initial level. These results suggest that taking an electrolyte and glucose solution during exercise decreases muscle susceptibility to cramps. It was concluded that drinking spring water while exercising in heat increases the susceptibility of muscles to cramps after exercise (downhill running) while taking rehydration solution decreases. This is in line with the findings of a previous study  showing that intake of spring water after dehydration makes muscles more susceptible to muscle cramps, but when rehydration solution was consumed, susceptibility to muscle cramps decreased. It should be further explored what and how many electrolytes should be contained in a drink for optimal results.
- Belval LN, Hosokawa Y, Casa DJ, Adams WM, Armstrong LE, Baker LB, Burke L, Cheuvront S, Chiampas G, González-Alonso J, Huggins RA, Kavouras SA, Lee EC, McDermott BP, Miller K, Schlader Z, Sims S, Stearns RL, Troyanos C, Wingo J. Practical hydration solutions for sports. Nutrients. 2019;11(7):1550.
- Cheuvront SN, Carter R, Sawka MN. Fluid balance and endurance exercise performance. Curr Sports Med Rep. 2003;2:202–8.
- Costa RJS, Teixeira A, Rama L, Swancott AJM, Hardy LD, Lee B, Camões-Costa V, Gill S, Waterman JP, Freeth EC, Barrett E, Hankey J, Marczak S, Valero-Burgos E, Scheer V, Murray A, Thake CD. Water and sodium intake habits and status of ultra-endurance runners during a multi-stage ultra-marathon conducted in a hot ambient environment: an observational field-based study. Nutr J. 2013;12
- Noakes TD. Fluid replacement during marathon running. Clin J Sport Med. 2003;13:309–18.
- Hoffman MD, Stuempfle KJ. Muscle cramping during a 161-km ultramarathon: comparison of characteristics of those with and without cramping. Sports Med Open. 2015;1:24.
- Armstrong LE, Maresh CM. The exertional heat illness: a risk of athletic participation. Med Exerc Nutr Health. 1993;2:125–34.
- Schwellnus MP, Derman EW, Noakes TD. Aetiology of skeletal muscle “cramp” during exercise: a novel hypothesis. J Sports Sci. 1997;15:277–85.
- Lau WY, Kato H, Nosaka K. Water intake after dehydration makes muscles more susceptible to cramp but electrolytes reverse that effect. BMJ Open Sport Exerc Med. 2019;5:e000478.
- Schwellnus MP, Allie S, Derman W, Collins M. Increased running speed and pre-race muscle damage as risk factors for exercise-associated muscle cramps in a 56 km ultra-marathon: a prospective cohort study. Br J Sports Med. 2011;45:1132–6.
- Giuriato G, Pedrinolla A, Schena F, Venturelli M. Muscle cramps: a comparison of the two-leading hypothesis. J Electromyogr Kinesiol. 2018;41:89–95.
- Maughan RJ, Shirreffs SM. Muscle cramping during exercise: causes, solutions, and questions remaining. Sports Med. 2019;49:115–24.
More about this topic:
- Exercise-Induced Nausea: Why? How to Help It?
- Cardiovascular Workouts: Hazards and Risks
- Should You Drink Sports Drinks Instead of Water? – HealthLine
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