A dangerous cycle of chronic illness and bone stress fractures has exposed the silent prevalence of Relative Energy Deficiency in Sport among male distance runners, following revelations by British athlete Jake Smith.
BBC Sport reported that the elite marathoner and half-marathon competitor spent years trapped in a punishing loop of competition, sickness and recurring injury before learning he was suffering from the condition, widely known as REDs. Despite producing world-class performances on the road, Smith found his body repeatedly breaking down under the strain of heavy training volumes that were critically under-fuelled.
Breaking the relentless cycle of under-fuelling
Smith's experience illustrates a broader and long-neglected medical crisis across distance running. According to BBC Sport, the Welsh runner continued to push through persistent exhaustion and multiple bone stress fractures, entirely unaware that his metabolic system was operating in a severe, chronic energy deficit.
The syndrome emerges when an athlete's nutritional intake fails to supply enough energy to support both the demands of high-performance training and basic biological survival. In response to sustained calorie deficits, the human body enters a conservation mode, shutting down non-essential physiological functions, compromising immune defences and stalling tissue regeneration.
A syndrome long miscast as exclusively female
Historically understood within sports science as the "female athlete triad"—a complex characterised by disordered eating, amenorrhoea and low bone density—the International Olympic Committee broadened the diagnosis in 2014 to REDs to reflect its universal impact across both sexes.
Yet widespread misconceptions endure, leaving many men in endurance disciplines to suffer in silence. Male competitors regularly dismiss red flags such as severe fatigue, recurrent respiratory infections, declining libido and stagnating performance as ordinary occupational hazards of rigorous training, rather than symptoms of physiological depletion.
The severe toll on testosterone and bone density
In male athletes, sustained energy deficiency carries acute clinical consequences. Insufficient caloric intake triggers a sharp decline in circulating testosterone, starving the body of the primary androgen required for muscle protein synthesis, metabolic health and bone turnover.
Over time, bone mineral density deteriorates substantially. This leaves runners exceptionally vulnerable to debilitating stress fractures across the sacrum, pelvis and lower limbs. Because men lack an obvious indicator analogous to the cessation of the menstrual cycle, the underlying energy deficit often goes completely undetected until a bone breaks or systemic illness forces a prolonged withdrawal from competition.
Cultural blind spots across elite endurance sport
The revelations highlighted by the BBC point to an enduring cultural blind spot within distance running, where an ultra-lean frame is frequently mistook for optimal athletic conditioning. High-performance coaches and dietitians are increasingly warning that the relentless focus on power-to-weight ratios often pushes athletes past their biological limits into clinical deficiency.
Addressing REDs requires dismantling the sporting stigma around nutritional intake. For competitors like Smith, learning that long-term athletic durability depends on fuelling properly—rather than subsisting on minimal calories—marks a vital shift toward safeguarding athlete welfare across the endurance landscape.
