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Correspondence to Dr Mohammed Ihsan, Research and Scientific Support, Aspetar Orthopedic and Sports Medicine Hospital, PO Box 29222, Doha, Qatar; [email protected]
The games of the XXXII Olympiad have been announced from 23 July to 8 August 2021, coinciding with the height of the Japanese summer. Heat acclimation/acclimatisation (HA) is the most important countermeasure athletes can adopt to safeguard their health and performance when competing in the heat. However, it is important for practitioners to recognise that repeated daily exposures to heat stress is a physiologically demanding endeavour. Prolonged heat exposure is characterised by increased thermal and cardiovascular strain, augmented glycogen utilisation and fluid losses, increased hormonal responses (ie, increased cortisol and catecholamine secretion), cytokinaemia and endotoxaemia, which may result in sleep and gastrointestinal disturbances, augmented lethargy and delayed physical recovery.1–3 For instance, consecutive days of training in the heat, particularly at high exercise intensities, can result in a state of over-reaching, despite signs of successful heat adaptation.4 It is therefore imperative to manage recovery when training in the heat, as accumulated fatigue may impact on the overall success of the HA programme, as well as interfere with the quality of other training sessions. This editorial aims to provide practitioners and coaches with an up-to-date synopsis of recovery strategies during HA (figure 1).
Pre-exercise nutritional strategies are crucial in limiting fluid and electrolyte imbalance during exertional heat stress, such that HA sessions can be optimally engaged while minimising the burden associated with replenishing deficits following exercise. Accordingly, athletes are advised to commence HA sessions euhydrated (ie, within 0.5 kg variation in body mass), with sodium intakes of 0.5–0.7 g/L generally recommended during sessions lasting longer than 60 min.1 5 The Institute of Medicine has highlighted that public health guidelines regarding sodium intake do not apply to individuals who lose large amounts of sodium through sweat on a daily basis, such as athletes training or competing in the heat.6 Recovery following heat training may also be influenced by the onset of endotoxaemia and systemic inflammatory response (ie, cytokinaemia), owing to exacerbated splanchic hypoperfusion. In this regard, carbohydrate (CHO) intake prior to (15 g, 6% solution) and during exercise (45 g/hour, 6% solution) has been shown to ameliorate such perturbations through improved splanchnic...