Strategies and factors associated with preparing for competing in the heat: a cohort study at the 2015 IAAF World Athletics Championships

Abstract

PurposeAssess exertional heat illness (EHI) history and preparedness in athletes competing in a World Athletics Championships under hot/humid conditions and identify the factors associated with preparedness strategies.MethodsOf the 207 registered national teams invited to participate in the study, 50 (24%) accepted. The 957 athletes (49% of all 1965 registered) in these teams were invited to complete a precompetition questionnaire evaluating EHI history, heat stress prevention (heat acclimatisation, precooling and hydration) and recovery. Responses from 307 (32%) athletes were separated in field events, sprints, middle-distance and long-distance running, and decathlon/heptathlon for analysis.Results48% of athletes had previously experienced EHI symptoms and 8.5% had been diagnosed with EHI. 15% heat acclimatised (∼20 days) before the championships. 52% had a precooling strategy, ice slurry ingestion (24%) being the most prevalent and women using it more frequently than men (p=0.005). 96% of athletes had a fluid consumption strategy, which differed between event categories (p<0.001). The most common volumes planned on being consumed were 0.5–1 L (27.2%) and ≥2 L (21.8%), water being the most frequent. 89% of athletes planned on using at least one recovery strategy. Female sex (p=0.024) and a previous EHI diagnosis increased the likelihood of using all 3 prevention strategies (p<0.001).ConclusionsAt a World Championships with expected hot/humid conditions, less than one-fifth of athletes heat acclimatised, half had a precooling strategy and almost all a hydration plan. Women, and especially athletes with an EHI history, were more predisposed to use a complete heat stress prevention strategy. More information regarding heat acclimatisation should be provided to protect athlete health and optimise performance at major athletics competitions in the heat.

Once- and twice-daily heat acclimation confer similar heat adaptations, inflammatory responses and exercise tolerance improvements

“…It is unsurprising therefore, that repeated steady‐state exercise during consecutive day HA, do not appear to be widely embraced by competitive athletes (Périard et al. ). Prescribing TDHA and specifically afternoon sessions, may also increase HA efficiency as time spent at the desired isothermic T re of >38.5°C was extended during afternoon compared to morning sessions (+14 vs. +6 min); yet ∆ T re were lower (+1.3°C vs. +1.6°C), thus requiring less exercise time to reach target temperatures due to circadian rhythm and higher resting T re .…”

“…Medium‐ (MTHA: 10–14‐days) and long‐term (LTHA: >14‐days) protocols which maximize adaptations exacerbate these challenges, a factor which may provide some explanation as to why, in spite of clear recommendations from the scientific community, only ~15% of athletes undertook HA prior to competition in heat stress (Périard et al. ).…”

“…Heat acclimation (HA) is an important preparation strategy preceding exercise-heat stress (P eriard et al 2015;Racinais et al 2015) to alleviate physiological strain (Nybo et al 2014), attenuate heat related illness (HRI) (Yamazaki 2012), improve thermal perception (Gonzalez and Gagge 1976) and exercise tolerance in hot (Nielsen et al 1993), and possibly temperate conditions (Lorenzo et al 2010). A variety of HA strategies currently exist, predominantly differentiated by exercise-heat stress volume, and/or intensity (Taylor 2014;Daanen et al 2017).…”

Physiological and perceptual responses to exercising in restrictive heat loss attire with use of an upper-body sauna suit in temperate and hot conditions

“…These are likely reasons for only 15% of athletes undertaking a recognised HA intervention prior to the IAAF World Championships, in spite of hot climates being forecast (Periard et al 2017). A proposed method for inducing (should access to an environmental chamber not be possible), or enhancing the efficiency (by accelerating the attainment of necessary physiological stimuli for adaptation) of HA is the wearing of clothing/garments which restrict heat loss during exercise (Dawson 1994).…”

New insights into preventing injuries and illnesses among elite athletics athletes

“…Among athletes participating at the World Athletics Championships, Périard et al 7 recently reported that approximately half of the athletes participating in the study had previously experienced heat illness symptoms (eg, cramping, severe headaches). However, only 15% of them reported having prepared specifically for the championships by undertaking heat training regimens 7…”