When the summer sun beats down on a football pitch, it’s not just the players who feel the heat. The game itself changes. New research from Saarland University in Germany and the University of Technology Sydney reveals that hotter conditions can subtly alter how football is played, from passing patterns to ball control.
The study, led by Edgar Schwarz and published in the European Journal of Sport Science, analysed 1,585 matches from four professional leagues, Germany’s Bundesliga 1 and 2, Spain’s La Liga, and Australia’s A-League, to understand how environmental temperature and heat stress affect match-play performance. The findings suggest that as temperatures climb, footballers perform fewer passes and dribbles, but achieve slightly higher accuracy.
The research arrives at a time when football governing bodies are increasingly grappling with the realities of climate change, rising wet-bulb globe temperatures (WBGT), and the growing number of games played under extreme heat.
Heat and human performance
Every football fan knows the sight of players slowing down during blistering afternoon matches, but the physiological reasons behind this phenomenon are intricate. Human thermoregulatory function allows athletes to maintain core temperature through sweating and heat exchange. Yet, when air temperature and humidity are high, the body’s ability to cool itself is impaired.
In hot conditions, heat dissipation is limited, forcing the body to rely on evaporative cooling, which is far less effective in humid environments. As core temperature rises, fatigue sets in sooner, affecting both physical and cognitive performance. Decision-making, reaction time, and working memory all degrade under thermal stress.
Football is as much a mental game as a physical one. Our data indicate that players may consciously or unconsciously adapt their style to conserve energy and maintain accuracy when heat levels rise.
– Edgar Schwarz
Analysing 1,585 matches across continents
To capture the nuances of heat and gameplay, the researchers extracted 27 performance indicators (PIs) that encompassed actions such as passing, dribbling, shooting, and defending. These were standardised across leagues using data from Opta’s optical tracking system, which combines human annotation, computer vision, and artificial intelligence.
Environmental data for dry-bulb temperature and wet-bulb globe temperature were retrospectively sourced from meteorological databases, including Meteostat and UBIMET GmbH. The WBGT index, which integrates air temperature, humidity, wind, and solar radiation, provides a more accurate measure of heat stress on players than temperature alone.
Using linear regression and mixed-effects models, the researchers identified how every 1°C increase in temperature correlated with changes in technical performance. Across the four leagues, eight of the 17 analysed parameters showed significant relationships with temperature and WBGT, particularly those linked to passing and dribbling.
Passes drop, accuracy rises
One of the most notable findings was the decrease in passing volume as temperatures increased. On average, the number of passes decreased by approximately 2.3 passes for each degree air temperature increased and 3.1 passes for each degree WBGT. Short passes suffered the most. The data also revealed fewer touches and take-ons, meaning players engaged less frequently with the ball during hotter games. This also affected touches in the “final third” of the pitch, so the area in front of the opponent’s goal and also passes into this dangerous area.
Yet, paradoxically, the success rate of passes slightly increased. As matches became more physically taxing, players seemed to compensate by prioritising precision over frequency. “In essence, players might become more conservative with their movements and decision-making,” explains Schwarz. “They pass less, but smarter, to avoid extensive running”. Another explanation for the observation could be a “decreased opponent pressure” Schwarz adds. As the defense is also decreasing running volumes, defensive marking and pressure might become reduced, leading to more time for the offense, including easier executions of passes.
While passing and dribbling declined, the number of key passes that directly led to a shot or goal remained largely unchanged. Shooting metrics such as goals scored and shots taken showed no significant correlation with temperature. The overall picture suggests that heat alters the rhythm of the match but not necessarily its outcomes.
Different leagues, same trend
The temperature ranges differed across the leagues. The A-League, played in warmer Australian climates, had the highest average WBGT at 18.1°C, with some matches exceeding 29°C. In contrast, Germany’s Bundesliga averaged around 9°C WBGT, and Spain’s La Liga around 15.5°C.
Despite these geographical variations, the pattern held: higher heat meant fewer passes, touches, and turnovers. Even when the leagues were analysed separately, the same small but statistically significant effects emerged. The consistency across continents strengthens the argument that these behavioural shifts are universal, not cultural or tactical.
This aligns with earlier isolated observations from international tournaments, including the 2014 and 2018 FIFA World Cups, where higher thermal stress was linked to altered passing patterns and reduced intensity. However, Schwarz’s study is the first to combine data across multiple professional leagues and seasons, giving it global relevance.
The cognitive cost of heat
The authors link these gameplay changes to cognitive fatigue induced by heat exposure. Elevated core temperatures impair the brain’s ability to perform complex tasks like decision-making, pattern recognition, and problem-solving – essential components in elite football.
Under hot conditions, players may adopt pacing strategies that minimise energy expenditure. This can translate into more conservative play, fewer risky dribbles and reduced pressing intensity. At the same time, the study found fewer turnovers, implying that players become more cautious in possession.
Implications for a warming world
The implications extend beyond sports performance. As global temperatures rise, tournaments increasingly face the risk of extreme heat events. Federations like FIFA and Football Australia already implement cooling breaks when WBGT exceeds set thresholds – 32°C for FIFA and 26°C for Australia.
However, as Schwarz notes, “Heat management policies focus on preventing heat illness, not on preserving the quality of play.” Understanding how environmental conditions affect match dynamics could influence not only health protocols but also match scheduling, player rotations, and training strategies.
There are also potential consequences for sports broadcasting and fan experience. If matches become slower and more methodical in the heat, it could subtly shift the visual style of football in hot climates. For coaches and analysts, quantifying these shifts could provide competitive advantages, especially in tournaments spanning multiple climatic zones.
Reference
Schwarz, E., Duffield, R., Novak, A. R., Compton, D. A., & Meyer, T. (2025). Associations between match‐play characteristics and environmental temperatures in four professional football leagues. European Journal of Sport Science. https://doi.org/10.1002/ejsc.12256
