Per-Cooling (Using Cooling Systems during Physical Exercise) Enhances Physical and Cognitive Performances in Hot Environments. A Narrative Review

Abstract

There are many important sport events that are organized in environments with a very hot ambient temperature (Summer Olympics, FIFA World Cup, Tour de France, etc.) and in hot locations (e.g., Qatar). Additionally, in the context of global warming and heat wave periods, athletes are often subjected to hot ambient temperatures. It is known that exercising in the heat induces disturbances that may provoke premature fatigue and negatively affects overall performance in both endurance and high intensity exercises. Deterioration in several cognitive functions may also occur, and individuals may be at risk for heat illnesses. To train, perform, work and recover and in a safe and effective way, cooling strategies have been proposed and have been routinely applied before, during and after exercise. However, there is a limited understanding of the influences of per-cooling on performance, and it is the subject of the present review. This work examines the influences of per-cooling of different areas of the body on performance in terms of intense short-term exercises (“anaerobic” exercises), endurance exercises (“aerobic” exercises), and cognitive functioning and provides detailed strategies that can be applied when individuals train and/or perform in high ambient temperatures.

A Matter of Degrees: A Systematic Review of the Ergogenic Effect of Pre-Cooling in Highly Trained Athletes

“…The skin temperature of athletes exposed to heat raises at a slower rate, as they sweat earlier than less-trained individuals [67]. This fact has led to suggestions that the application of cooling devices before exercise does not provide any beneficial effects [12]. However, this hypothesis may depend on athletes' morphology.…”

“…Bearing in mind the particular circumstances in which highly trained athletes compete and in looking for a major performance, sport scientists have put all their effort to find cooling techniques to reduce central temperature and delay the onset of fatigue [11]. Thus, athletes can implement cooling before or during competition to facilitate heat dissipation and increase heat storage capacity, prolonging the time in which exercise intensity can be maintained before reaching a critical top limit [12].…”

COVID-19 and heat waves: New challenges for healthcare systems

“…Spires, M., Kadihasanoglu, 2019) •Establishing shorter work cycles in overheated rooms, more frequent breaks, changed shift patterns, better staff shift schedules ( Jacklitsch et al, 2016 ) •Planning/shifting longer activities with the need for infection control to times of day/building areas with lower temperature/solar radiation •Taking organisational measures within the team, e.g. for early symptoms of heat stress -> stop working in the heat -> seek cooler premises and direct help (colleagues) •Encouraging mindfulness of oneself and colleagues; fostering open communication of problems in the institution ( www.ghhin.org/assets/technical-brief-COVID-and-Heat-final.pdf ) •Wearing adequate clothing under the protective equipment, if necessary, consider special clothing (cooling vests) in particularly stressful conditions ( Bach et al, 2019 ; Daanen et al, 2020 ; Gao et al, 2018 ; Luze et al, 2020 ; Morris et al, 2020 ; Quinn et al, 2017 ; Teunissen et al, 2014 ; Watson et al, 2019 ) •Consideration of the possible overlap of hot spells (increased need for personnel) with the summer holidays (less available personnel due to increased holiday volume) in the duty roster or holiday planning (consider heat warnings) ➢ Personal measures •Heat acclimatization and aerobic conditioning to enhance heat tolerance ( Alhadad et al, 2019 ; Douzi et al, 2020 ; Lee et al, 2008 ; Leyk, 2019 ; Morris et al, 2020 ) Start to work precooled ( www.ghhin.org/heat-and-covid-19/PPE ) ( Alhadad et al, 2019 ; Daanen et al, 2020 ; Douzi et al, 2020 ; McLellan et al, 2013 ; Morris et al, 2020 ) •Encourage staff to self-monitor their hydration; drinking unsweetened liquids/sports drinks/cold fluids/ice slushies before and during work; self-control of the body's own fluid balance (toilet); start work cooled and well hydrated ( Foster et al, 2020 ; Lee et al, 2020 , ...…”

Playing tennis in hot environment: Applied strategies and new directions

“…Performing a sport such as tennis in the heat is physically demanding due to reduced neuromuscular function, increased individual's core temperature, altered skeletal muscle metabolism and increased cardiovascular strain due to thermoregulation (Douzi, Dupuy, Theurot, Smolander, & Dugué, 2020;Nybo, Rasmussen, & Sawka, 2014). Moreover, because of the heat, psychological strain via arousal (Nielsen, Hyldig, Bidstrup, Gonzalez-Alonso, & Christoffersen, 2001), reduced motivation (Bridge, Weller, Rayson, & Jones, 2003), increase in negative affects (Gaoua, Grantham, Racinais, & El Massioui, 2012) and decrease in positive affects (Robin et al, 2019) can negatively influence sport performance.…”