How Hydration Can Affect Concentration During a Close Football Match (European Football)

It is the 80th minute, the score is 1-1, and you have not had a drink since half-time. A ball is played into the space behind your full-back, and you have less than a second to decide to step up or to drop and cover. Your legs feel heavy, the sun has been on the pitch all afternoon, and the last 10 minutes will be decided by moments like this one. On a warm afternoon, a footballer in that position has often lost 2% or more of their body mass since kickoff, a deficit reported more consistently in football than in any other team sport studied.

Sweat Rates and Match Deficits

A 2017 review in Sports Medicine compared fluid balance across team sports and found high sweat rates in American football, basketball, rugby, tennis, and ice hockey as well, though deficits in those sports were generally under 2%. Mean sweat rates in football studies ranged from 0.3 to 2.5 liters an hour, across conditions from 5°C to 43°C.

Heat alone does not decide the size of the deficit. Players in one comparison lost 1.8% of body mass indoors at 21°C and 1.9% outdoors at 43°C, even though their sweat rates were 1.6 and 2.5 liters an hour. Players drank more in the heat, and the opportunities to drink determined the final number as much as the temperature did. In a normal league match, half-time is the only scheduled stoppage, so those opportunities are limited.

Concentration Scores After Fluid Loss

Three studies have measured concentration in footballers who were losing fluid, and the effects were smaller than the physical ones. Edwards and colleagues gave players a number identification test after a 45-minute match. Scores were similar when they drank water and finished at 0.7% body mass loss, when they only rinsed their mouths and reached 2.1%, and when they drank nothing and reached 2.4%. A second study, in semiprofessional players, found the same result at 1.4% and 2.4%.

The third study took place in heat of 34°C, with players completing a battery of cognitive tests at 3 points in each match. Losses of up to 2.5% body mass slowed reaction time on a working memory task and had no measurable effect on the other tests. Blood glucose and core temperature explained more of the speed and accuracy results than fluid loss did.

In a close match in summer, the decline in decision quality late in the game may have as much to do with heat and falling blood sugar as with water, and the 3 factors build up together over 90 minutes. Bottles of hydration drinks with carbohydrate in them supply fluid and glucose in the same few mouthfuls, which is useful in a half-time interval that the Laws of the Game limit to 15 minutes.

Attention Across Wider Research

Outside football, the evidence is larger and points in the same direction at higher deficits. A 2018 meta-analysis in Medicine and Science in Sports and Exercise pooled 33 studies and 413 participants with fluid losses from 1% to 6% of body mass. Cognitive performance was impaired by a small amount overall, with an effect size of -0.21, and the effect was twice as large when losses exceeded 2% as when they stayed at or below it, with the strongest effects on attention, executive function, and motor coordination. Those are the 3 functions a defender uses when tracking a runner and timing a tackle.

Skills and Sprints in the Final 15 Minutes

McGregor and colleagues put semiprofessional players through a 90-minute shuttle running protocol designed to resemble a match. With no fluid, they lost 2.4% of body mass and their dribbling skill was 5% worse, while the group that drank held its performance. Two other studies using the same protocol found no effect of fluid restriction on passing or shooting. Running capacity was more sensitive. In the Edwards study, the players whose concentration scores held steady covered 13% to 15% less distance on an intermittent running test after the match when they had reached 2.1% or 2.4% body mass loss, compared with the trial in which they drank water.

Across 90 minutes, fluid restriction of about 2% to 4% did not change average 15-meter sprint times, but in the McGregor study sprint times were longer in the final 15-minute block when fluid was withheld. A close match is often settled in that same period, by a run in behind or a recovery sprint. Seven matchweeks into the 2025-26 Premier League season, Opta found that late goals had reached a record share, with 13.2% of all goals scored in the 90th minute or later, and suggested that tiring defenders could be one reason.

Drinking Opportunities and the 2026 Water Breaks

Football gives players few chances to drink. Outside half-time, players take fluid during stoppages for injuries and substitutions, from bottles placed along the touchline. At the 2026 World Cup, FIFA introduced mandatory water breaks of 3 minutes at about the 22nd minute of each half in every match, regardless of weather, in place of the heat-triggered cooling breaks first used at the 2014 World Cup in Brazil. The change came after the 2025 Club World Cup in the United States, where some matches were played in temperatures above 38°C and Chelsea midfielder Enzo Fernández said he felt "really dizzy" on the pitch. Coaches used the World Cup breaks for instructions as well, with France manager Didier Deschamps saying the pause gave him a chance to adjust a couple of things, so the time available for drinking is shorter than the full 3 minutes.

Fluid Status at Kickoff

Many players start the match behind. In a 2025 study of collegiate players across 38 practices and 17 games, urine tests showed that more than half began exercise already underhydrated in every condition studied. Total distance covered and fast running distance in games both fell as the percentage of body mass lost rose. Games played in cool conditions produced a higher share of players at 2% body mass loss or more than games in the heat, where players drank enough to finish overhydrated.

Among elite male footballers from a UEFA national team, tested across 3 Nations League camps in 2020, 20 of 23 were dehydrated on the first morning of the first camp. With daily urine monitoring and coaching on fluid intake, 52% were dehydrated 2 days before a match and 6% on match day. A player who begins 1% down and loses another 2% during the game reaches the level where attention effects become more likely before the final whistle. The drinking done in the 24 hours before kickoff is the part of the process that does not depend on the referee stopping play.

Open Questions on Late-Match Lapses

The studies agree that a well-hydrated player keeps dribbling skill and late sprint speed better than a player who drank nothing. They do not yet agree on how much of a late lapse in concentration comes from fluid loss alone, separate from heat and falling blood glucose. The fixed breaks at the 2026 World Cup produced a new kind of match to study, with 2 guaranteed drinking points in every game. If fluid and blood glucose fall together while core temperature climbs in the last 15 minutes, which of them decides the error that loses the match?