Jeppesen Jan S, Hellsten Ylva, Melin Anna K, Hansen Mette
Department of Nutrition, Exercise and Sport, the August Krogh Section for Human Physiology, University of Copenhagen, Copenhagen, Denmark.
Department of Sport Science, Linnaeus University, Växjö, Sweden.
Scand J Med Sci Sports. 2025 Jun;35(6):e70089. doi: 10.1111/sms.70089.
Many athletes and coaches believe that reducing body mass can improve the power-to-body mass ratio and improve exercise performance. This narrative review aims to characterize the effects of short-term (days to weeks) severe (< 30 kcal/kg Fat Free Mass/day) low energy availability (LEA) on exercise performance and physiological parameters related to health and training adaptations in female athletes. The latter is based on the prevalence of LEA being higher among female athletes, and most of the research is conducted on this population. In addition, we briefly address emerging evidence on short-term severe LEA in male athletes to highlight potential sex differences in physiological responses and performance outcomes. Short-term severe LEA triggers energy-conserving responses, leading to disruption in several crucial physiological systems, including suppression of the hypothalamic-pituitary-ovarian axis, decrease in triiodothyronine and insulin-like growth factor I hormones, reduction in resting metabolic rate, and comprised protein turnover in collagen-rich tissues. If these detrimental effects of short-term severe LEA are not reversed, they can progress to long-term problematic LEA, resulting in hypothalamic amenorrhea, lowering of bone mineral density, increased injury risk, and impaired exercise performance. Recent studies further underscore the detrimental impact of short-term severe LEA in female athletes, revealing suppressed muscle protein synthesis, increased cortisol levels, altered immune function, enhanced fat utilization during exercise, and direct impairments in power, sprinting, and endurance exercise performances despite reductions in body mass. These findings highlight the concerns about the trade-offs between short-term severe LEA for body mass reduction and the ability to maintain optimal physiological function for exercise performance. Further, they challenge the widespread assumption that body mass reduction always improves exercise performance, emphasizing a need for case-by-case considerations within the sporting environment.
许多运动员和教练认为，减轻体重可以提高力量与体重比，从而提升运动表现。本叙述性综述旨在描述短期（数天至数周）严重（<30千卡/千克去脂体重/天）低能量可利用状态（LEA）对女运动员运动表现以及与健康和训练适应相关的生理参数的影响。后者是基于女运动员中LEA的患病率较高，且大多数研究是针对这一人群进行的。此外，我们简要介绍了男运动员短期严重LEA的新证据，以突出生理反应和运动表现结果方面潜在的性别差异。短期严重LEA会引发节能反应，导致几个关键生理系统紊乱，包括下丘脑 - 垂体 - 卵巢轴受抑制、三碘甲状腺原氨酸和胰岛素样生长因子I激素减少、静息代谢率降低以及富含胶原蛋白组织中的蛋白质周转受损。如果短期严重LEA的这些有害影响得不到扭转，可能会发展为长期有问题的LEA，导致下丘脑性闭经、骨密度降低、受伤风险增加以及运动表现受损。最近的研究进一步强调了短期严重LEA对女运动员的有害影响，揭示了肌肉蛋白质合成受抑制、皮质醇水平升高、免疫功能改变、运动期间脂肪利用率提高，以及尽管体重减轻但力量、短跑和耐力运动表现直接受损。这些发现凸显了对于为减轻体重而采用短期严重LEA与维持运动表现的最佳生理功能能力之间权衡的担忧。此外，它们挑战了体重减轻总能提高运动表现这一普遍假设，强调在体育环境中需要逐案考虑。
