Energy Availability in Athletics: Health, Performance, and Physique

Abstract

The reported prevalence of low energy availability (LEA) in female and male track and field athletes is between 18% and 58% with the highest prevalence among athletes in endurance and jump events. In male athletes, LEA may result in reduced testosterone levels and libido along with impaired training capacity. In female track and field athletes, functional hypothalamic amenorrhea as consequence of LEA has been reported among 60% of elite middle- and long-distance athletes and 23% among elite sprinters. Health concerns with functional hypothalamic amenorrhea include impaired bone health, elevated risk for bone stress injury, and cardiovascular disease. Furthermore, LEA negatively affects recovery, muscle mass, neuromuscular function, and increases the risk of injuries and illness that may affect performance negatively. LEA in track and field athletes may occur due to intentional alterations in body mass or body composition, appetite changes, time constraints, or disordered eating behavior. Long-term LEA causes metabolic and physiological adaptations to prevent further weight loss, and athletes may therefore be weight stable yet have impaired physiological function secondary to LEA. Achieving or maintaining a lower body mass or fat levels through long-term LEA may therefore result in impaired health and performance as proposed in the Relative Energy Deficiency in Sport model. Preventive educational programs and screening to identify athletes with LEA are important for early intervention to prevent long-term secondary health consequences. Treatment for athletes is primarily to increase energy availability and often requires a team approach including a sport physician, sports dietitian, physiologist, and psychologist.

International Association of Athletics Federations Consensus Statement 2019: Nutrition for Athletics

“…• Large dependency of endogenous fat energy substrate but requires a constant supply of exogenous CHO energy substrate for synergistic energy provisions and prevention of metabolic fatigue Theme 2. Energy Availability in Athletics: Managing Health, Performance, and Physique (Melin et al, 2019) Dietary energy must meet the energy cost of an Athlete's training load and competition program as well as support the body's nonsport function/activities related to health and well-being. The conventional interest in energy targets the concept of energy balance where differences between dietary energy intake and total daily energy expenditure create opportunities for changes in body composition to store or utilize body fat and protein.…”

Contemporary Nutrition Strategies to Optimize Performance in Distance Runners and Race Walkers

“…Importantly, it helps the athlete to integrate the inevitability or benefits of brief periods of controlled low energy availability within the endurance training framework. Problems associated with chronic or severe low energy availability, known as relative energy deficiency in sports, are well known (Mountjoy et al, 2018); specific issues in relation to Athletics are covered by Melin et al (2019).…”

Low energy availability in male athletes: A systematic review of incidence, associations, and effects

“…From the studies examined, 3 out of 7 CS studies and 1 out of 3 RCT studies included female participants, but the results of male only athletes are considered within this review. Clinical LEA (<30 kcal/kg LBM/d) or subclinical LEA (36 ± 6 kcal/kg LBM/d) was prevalent in all of the cross‐sectional studies (Table ). Participants included jockeys, wrestlers, cyclists, and endurance athletes .…”

“…Optimal levels of EA are difficult to determine in the athletic population; however, according to Loucks and Thuma, for young and healthy sedentary females, energy balance equals 0 kcal/d when EA = 45 kcal/kg FFM/d (FFM = free fat mass). Research has shown subclinical EA of 44‐30 kcal/kg FFM/d poses no serious threat to physiological responses in female athletes . At present, there is no definitive number to determine LEA, and contrary to what has previously been accepted, recent research from Lieberman et al has shown that EA < 30 kcal/kg LBM/d does not predict menstrual disturbances such as luteal phase defects, oligomenorrhea, and anovulation.…”

“…40 kcal/kg FFM/d for recreationally active males appears to be a threshold for physiological function. Recently, EA classifications for both male and female athletes have been proposed as guidelines, rather than diagnostic tools (Table ) …”