Does aerobic fitness help to beat the heat?

An investigated of the individual impact, and the collective effect of environmental conditions and aerobic fitness on performance.

Cody Roberts

By Cody Roberts
Last updated: April 28th, 2024
3 min read


  1. Background & Objective
  2. What They Did
  3. What They Found
  4. Practical Takeaways
  5. Reviewer’s Comments
  6. About the Reviewer

Original study

Benjamin, C. L., Hosokawa, Y., Curtis, R. M., Schaefer, D. A., Bergin, R. T., Abegg, M. R., and Casa, D. J. (2020). Environmental Conditions, Preseason Fitness Levels, and Game Workload: Analysis of a Female NCAA DI National Championship Soccer Season. Journal of Strength and Conditioning Research, 34(4); 988-994.

Click here for abstract

Background & Objective

Aerobic fitness and environmental conditions (e.g. air temperature and humidity) require a coach’s attention and adaptation strategies to maximise performance, especially with outdoor sports (e.g. football).

Improvements in aerobic fitness increase resiliency to (high) workload, but does it also lessen the impact of environmental stress? This study investigated the individual impact, and the collective effect of environmental conditions and aerobic fitness on performance.

What They Did

The environmental conditions and in-game performance data for nineteen NCAA DI collegiate female soccer athletes across a season were collected. The yo-yo intermittent recovery test level 1 (YYIRTL1) was performed prior to the start of the season for a baseline assessment of physical work capacity. Ambient temperature (TA), relative humidity (RH), and wet-bulb globe temperature (WBGT) were the environmental conditions recorded at the beginning of each game.

Relative distance (TD), percentage of high-speed running distance (%HSD), and percentage of high metabolic load (% HML) for each athlete that played >60 min were assessed using GPS data. Environmental conditions and physical performance were reviewed for interaction, impact, and relationship.

What They Found

The primary findings of this study were:
⇒ High-risk environmental conditions (i.e. RH 50-75 % and WBGT >25 °C) did not impact the TD completed.

⇒ A negative relationship between WBGT and measures of %HSD and %HML, specifically, the highest values in speed and change of direction occurred at lower WBGT values.

⇒ A superior YYIRTL1 result (i.e. physical work capacity) possibly protected athletes from an increased WBGT by showing less detriment to %HSD, however, this had no bearing on TD or %HML.

⇒ Performance data appeared to be impacted by WBGT by variable levels, irrespective of an athlete’s physical work capacity.

Practical Takeaways

⇒ Heat acclimatisation can take 8-14 days and is the most important strategy to reduce the impact of environmental stress on performance. Progressively build to the volume or intensity of competition-specific training for two weeks before the event in expected environmental conditions.

  • Begin this progression with a session that is half the duration but at similar intensity expected in competition.

⇒ A focus on fluid intake (i.e., hydration), before, during, and after competition will assist with the body’s thermoregulation process and help optimise physiological performance capabilities. This strategy should be implemented consistently throughout training days.

  • Assess hydration and fluid loss through change in bodyweight pre- and post-competition, as well as using urine colour as a potential representation of hydration status.

Rehydration post-game, as well as cooling strategies (e.g. coldwater immersion or ingesting an icy fluid), can assist in reducing environmental heat stress and improve recovery rate between competitions.

Reviewer’s Comments

“Performance is multi-factorial and there are countless variables that interplay to impact performance, some of which are outside of the coaches’ and athletes’ control (e.g., environmental conditions or gender). Focusing on what can be controlled is the most effective strategy to prepare for tolerance and maximise performance. Athletes can optimise their overall preparedness and daily readiness by training in conditions specific to the competitive environment, with proper management of both the volumes and intensities anticipated, consuming adequate calories and fluids, and getting sufficient sleep (both quantity and quality) on a regular basis.

Consequently, all these efforts are not enough to eliminate the physiological impact of an uncontrollable factor like high environmental stress. Modifying tactical strategies during competition (e.g., pacing) or increasing in-game substitutions can help to sustain an athlete’s physical abilities across a game with high environmental stress.”

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Cody Roberts

Cody Roberts

Cody has been a strength and conditioning coach within NCAA Division I sports since 2008. He currently works in Olympic sports at the University of Iowa. He holds a Masters degree in Exercise Science from the University of Kansas (‘10). A former collegiate discus and hammer thrower (University of Kansas ‘07), Cody has also served as an adjunct professor within the Health & Human Physiology department at Iowa, as well a written over 200 research reviews for the Performance Digest since joining the Science for Sport team in 2019.

Cody is a Certified Strength and Conditioning Specialist (CSCS) through the National Strength and Conditioning Association, a Strength & Conditioning Coach Certified (SCCC) through the Collegiate Strength and Conditioning Coaches Association, and a USAW Certified Sport Performance Coach from USA Weightlifting.

The entire psychophysiological process of coaching and athletic development is what drives Cody to learn and engage others daily to best serve and develop the athletes he works with. In his role, he has numerous resources at his disposal (e.g. GPS, force plates, tensiomyography, and other testing/monitoring tools). His experience and application of these tools, implementing consistent and sustainable monitoring strategies, make him an excellent resource for all things technology and monitoring. Aiming to maximize the quest for optimal performance through a holistic and scientific approach.

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