Is this a big issue?  

This article covers the basics around sweat loss and why we sweat, how excessive sweat loss can lead to dehydration and how dehydration can reduce our performance. We then take a deeper look and apply dehydration to cricket, looking at studies showing how dehydration can impair cricket performance. Finally, we will cover some strategies to minimise dehydration when playing cricket in hot conditions. 

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Why do we sweat and how can dehydration affect health and exercise performance?

During exercise, significant body heat is generated, which activates millions of sweat glands in the body. Sweat glands produce sweat, which then evaporates off the surface of the skin and in doing so, takes heat energy away with it, cooling the body (1). This sweat response is crucial - maintaining body temperature within narrow limits ensures that the body functions optimally and prevents heat stress. Without these heat loss mechanisms, a 60 kg elite runner completing 10 km in 27 minutes would collapse and die due to a rise in body temperature after 3.2 km (2,3). In very hot environments, close to 100% of heat loss is due to sweating (4). 

So, we now understand that this sweat response is crucial to keep us alive, but it comes with one big issue – fluid loss! Prolonged exercise in the heat always increases the risk of dehydration occurring, which has potential negative effects on both performance and health. 

Our blood is made up of a number of components – red blood cells, white blood cells, platelets and plasma. Plasma is the fluid component of blood and this is what is lost to form sweat. Therefore, during prolonged exercise in the heat – we lose sweat and therefore get reduced blood plasma volume. This reduced blood plasma volume has many negative physical and psychological effects such as: reduced blood flow to the muscles and brain, increased body temperature, increased heart rate, reduced aerobic fitness, increased thirst, fuel depletion, lower mood and increased perception of effort (5). 

Dehydration can also have many negative health effects, such as: thirst, dry skin, fatigue, dark urine colour, muscle cramps, headaches, passing out, heart palpitations, poor mood, reduced cognitive performance, digestion issues and in extreme cases, death (6, 7). 

A reduced plasma volume means that we pump less blood out of the heart per beat (reduced stroke volume). Heart rate must increase in response to this reduction in stroke volume, in order to maintain blood flow and oxygen delivery to the working muscles. This progressive increase in heart rate (despite intensity remaining the same) during prolonged exercise in the heat is known as cardiovascular drift. Cardiovascular drift can affect performance because it reduces aerobic fitness and exercise performance and increases perceived level of effort (8). 

So, dehydration can have negative effects on human health and exercise performance, but how relevant is this in cricket? Let’s find out! 

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How common is dehydration during cricket match play and how does this affect performance? 

Given the long-playing hours involved, one-day and multiple-day formats provide the biggest risk of dehydration. Having said that, given the high-intensity nature of T20 cricket, T20 match play in a hot environment also poses a significant risk of dehydration. Take a day of test cricket for example – players spend about 6 hours on the field playing per day, performing many high-intensity actions throughout, which will result in substantial sweat losses. This sweat loss will result in reductions in blood plasma volume, which will consequently result in a reduction in body mass due to reduced total body water. Therefore, body mass loss (often expressed as a %) can be taken as a measure of dehydration during physical activity. Studies have generally shown that a body mass loss of greater than 2% results in reductions in performance (9), but some studies have shown performance reductions with more mild dehydration of less than 2% (10, 11). 

There are opportunities to consume fluid on the boundary and during breaks in play. However, it is practically challenging to consume enough fluid to limit body mass loss to less than 2%, especially if playing in hot and humid conditions such as in the Indian subcontinent (11).

One study found that fast bowlers playing in hot conditions (27.1 degrees) had a mean dehydration of 4.3% body mass loss after just 2 sessions of play (12)! This is over double the 2% threshold whereby performance decreases are thought to occur – and so performance implications are likely to be huge. 

A recent study showed evidence of these performance effects in cricket (13). They performed 2 trials – a fluid provision trial (FP), where body mass loss was limited to just 0.6% and a fluid restriction trial (FR), where body mass loss was 3.7%. The study found that bowling speed, bowling accuracy, throwing speed, throwing accuracy and running between the wickets was impaired in the FR trial compared to the FP trial. Another study (14) found that moderate dehydration (2.8% body mass loss) impaired bowling accuracy, but not bowling speed.  These studies support the idea that dehydration can significantly impair cricket performance – even after just a 2-hour training session – imagine how performance could be impaired during when batting/fielding all day in hot conditions if sufficient fluid was not consumed! 

So, we have established that dehydration can reduce cricket performance and in extreme cases, can be harmful to health. But how do we overcome this? The next section aims to tackle this question.

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Practical recommendations to reduce dehydration during cricket match play

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Begin the game well hydrated

One important but often overlooked aspect of remaining well hydrated during exercise is to ensure you begin the game well hydrated! A review looking at the hydration status of footballers found that 41.3% began matches dehydrated and 79.6% began training sessions dehydrated (15). The same has yet to be explored in cricketers but I believe this figure would be the same if not higher! To overcome this, ensure you are intaking adequate fluids every day, especially pre-match, adjusting as necessary for games and training. The National Athletic Trainers' Association recommends drinking ~500-600 ml of fluid 2-3 hours before exercise and then another ~200-300 ml 10 -20 minutes prior to exercise to ensure you begin the game well hydrated (16). 

A way to monitor hydration status would be through tracking urine colour (17, 18) – aiming for clear or slightly yellow urine colour. However, urine colour is not always accurate on an acute time-scale, especially if you have just drunk large volumes of water in a short time frame (urine may be clear but hydration status may be inadequate) – so having a hydration plan based on your individual needs is crucial.

Hydrate during the game

Ensure you consume adequate fluids during the game, with a very rough recommendation being around 400-1500 mL per hour of fluid containing both carbohydrate and sodium (see below for the importance of sodium). You want to aim for nearer the top end of this if you’re playing in very hot conditions, you’re elite and/or you’re batting and nearer the lower end if you’re recreational, fielding or it’s cooler. 

We also lose electrolytes (sodium and potassium) in sweat. Electrolytes play vital roles in nerve function, muscle activation and fluid balance. Sodium is the main electrolyte lost in sweat and so sodium-rich beverages can be crucial to restore electrolyte balance, improve rehydration and fluid retention (21). When adding sodium to a beverage, you lose less of the fluid you consume through urine and retain more of it. Addition of potassium and chloride may also help too (21). Commonly consumed sports drinks such as gatorade contain both carbohydrates and electrolytes and have good hydrating properties (22), however they still contain inadequate sodium to restore sodium balance, so perhaps adding an electrolyte tablet and some squash (for carbohydrate content) to water may be the best choice for optimal rehydration.

As a minimum we want to reduce body mass loss to <2%. The research suggests that drinking to thirst only is inadequate to prevent dehydration, especially when exercise is longer than 90 mins or conditions are hot (19), so have a hydration plan and stick to it! However, be careful not to drink too much, as this can result in a condition known as hyponatremia (20) – where there is not enough sodium in the body and this can be potentially harmful! Consult a sports nutrition professional if you feel that you are drinking too much/too little on a regular basis during games/training. 

Consume carbohydrate in beverages during and after exercise

This has two main benefits: 

1. Increases hydration via slowing of gastric emptying (the rate fluid is absorbed from the stomach) (12) – this means the water in your blood “spikes” slower, so you retain more of what you consume and lose less in urine!
2. Increases blood glucose concentration which can be used as fuel during performance OR increases muscle carbohydrate stores if consumed after training/games which can improve recovery

Consume protein beverages

Consume beverages that contain protein after exercise. Protein increases fluid retention through increasing something called oncotic pressure (21), which draws more water into the blood. Consuming a beverage with protein has a second benefit – it increases muscle protein synthesis which can benefit recovery and muscle growth. Milk/chocolate milk is a great example of a very hydrating beverage with excellent recovery benefits, since it contains carbohydrate, protein and electrolytes!

Replenish fluids after the game

Replenish fluids after the game, particularly if the next game/training is the next day/soon. Aim to consume 150% estimated sweat loss in fluids – so if your estimated sweat loss is 1L – drink 1.5L of fluid after the game (21). You can estimate sweat loss through measuring body mass loss after a game and assuming that if you lost 1kg, you lost 1L of sweat. For a more accurate sweat loss value, contact a sports nutrition professional. It is better to drink slowly and regularly rather than too quickly because this reduces urine output so you retain more of the water you consume (21).

Avoid Alcohol

Avoid alcohol! Alcohol is a diuretic, which means it increases urine output, which can cause dehydration (21). If you’re playing/training the following day, then it is best to refrain from alcohol consumption all together. If not, then a couple of drinks is unlikely to impact on rehydration and recovery if sufficient non-alcoholic fluid is consumed, but large volumes of alcohol definitely will! 

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Sean Sage BSc, MSc (@sagesportsci) 

References 

1. Casa DJ, Cheuvront SN, Galloway SD, Shirreffs SM. Fluid Needs for Training, Competition, and Recovery in Track-and-Field Athletes. Int J Sport Nutr Exerc Metab. 2019;29(2):175-180. doi:10.1123/ijsnem.2018-0374 
2. Dennis SC, Noakes TD. Advantages of a smaller bodymass in humans when distance-running in warm, humid conditions. Eur J Appl Physiol Occup Physiol. 1999;79(3):280-284. doi:10.1007/s004210050507
3. Nielsen B. Olympics in Atlanta: a fight against physics. Med Sci Sports Exerc. 1996;28(6):665-668. doi:10.1097/00005768-199606000-00004
4. Gagge AP, Gonzalez RR (1996). Mechanisms of heat exchange: Biophysics and physiology. In: M.J. Fregly & C.M. Blatteis (Eds.), Handbook of physiology: Environmental physiology (pp. 45–84). Bethesda, MD: American Physiological Society.
5. James LJ, Funnell MP, James RM, Mears SA. Does Hypohydration Really Impair Endurance Performance? Methodological Considerations for Interpreting Hydration Research. Sports Med. 2019;49(Suppl 2):103-114. doi:10.1007/s40279-019-01188-5
6. Popkin BM, D'Anci KE, Rosenberg IH. Water, hydration, and health. Nutr Rev. 2010;68(8):439-458. doi:10.1111/j.1753-4887.2010.00304.x 
7. Taylor K, Jones EB. Adult Dehydration. [Updated 2022 May 15]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK555956/ 
8. Wingo JE, Ganio MS, Cureton KJ. Cardiovascular drift during heat stress: implications for exercise prescription. Exerc Sport Sci Rev. 2012;40(2):88-94. doi:10.1097/JES.0b013e31824c43af 
9. Murray B. Hydration and physical performance. J Am Coll Nutr. 2007;26(5 Suppl):542S-548S. doi:10.1080/07315724.2007.10719656
10. Bardis CN, Kavouras SA, Kosti L, Markousi M, Sidossis LS. Mild hypohydration decreases cycling performance in the heat. Med Sci Sports Exerc. 2013;45(9):1782-1789. doi:10.1249/MSS.0b013e31828e1e77
11. Wilk B, Meyer F, Bar-Or O, Timmons BW. Mild to moderate hypohydration reduces boys' high-intensity cycling performance in the heat. Eur J Appl Physiol. 2014;114(4):707-713. doi:10.1007/s00421-013-2803-8 
12. Gore CJ, Bourdon PC, Woolford SM, Pederson DG. Involuntary dehydration during cricket. Int J Sports Med. 1993;14(7):387-395. doi:10.1055/s-2007-1021197
13. Gamage JP, De Silva AP, Nalliah AK, Galloway SD. Effects of Dehydration on Cricket Specific Skill Performance in Hot and Humid Conditions. Int J Sport Nutr Exerc Metab. 2016;26(6):531-541. doi:10.1123/ijsnem.2016-0015
14. Devlin LH, Fraser SF, Barras NS, Hawley JA. Moderate levels of hypohydration impairs bowling accuracy but not bowling velocity in skilled cricket players. J Sci Med Sport. 2001;4(2):179-187. doi:10.1016/s1440-2440(01)80028-1 
15. Chapelle L, Tassignon B, Rommers N, Mertens E, Mullie P, Clarys P. Pre-exercise hypohydration prevalence in soccer players: A quantitative systematic review. Eur J Sport Sci. 2020;20(6):744-755. doi:10.1080/17461391.2019.1669716
16. Judge LW, Bellar DM, Popp JK, et al. Hydration to Maximize Performance and Recovery: Knowledge, Attitudes, and Behaviors Among Collegiate Track and Field Throwers. J Hum Kinet. 2021;79:111-122. Published 2021 Jul 28. doi:10.2478/hukin-2021-0065 
17. Armstrong LE, Maresh CM, Castellani JW, et al. Urinary indices of hydration status. Int J Sport Nutr. 1994;4(3):265-279. doi:10.1123/ijsn.4.3.265
18. Armstrong LE, Soto JA, Hacker FT Jr, Casa DJ, Kavouras SA, Maresh CM. Urinary indices during dehydration, exercise, and rehydration. Int J Sport Nutr. 1998;8(4):345-355. doi:10.1123/ijsn.8.4.345 
19. Kenefick RW. Drinking Strategies: Planned Drinking Versus Drinking to Thirst. Sports Med. 2018;48(Suppl 1):31-37. doi:10.1007/s40279-017-0844-6
20. Shirreffs SM. Restoration of fluid and electrolyte balance after exercise. Can J Appl Physiol. 2001;26 Suppl:S228-S235. doi:10.1139/h2001-057
21. Evans GH, James LJ, Shirreffs SM, Maughan RJ. Optimizing the restoration and maintenance of fluid balance after exercise-induced dehydration. J Appl Physiol (1985). 2017;122(4):945-951. doi:10.1152/japplphysiol.00745.2016
22. Shirreffs SM, Aragon-Vargas LF, Keil M, Love TD, Phillips S. Rehydration after exercise in the heat: a comparison of 4 commonly used drinks. Int J Sport Nutr Exerc Metab. 2007;17(3):244-258. doi:10.1123/ijsnem.17.3.244

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