For British long-distance runner Jake Smith, a professional contract with Nike and a place representing Great Britain on the global stage came alongside a relentless, punishing cycle of race, illness, injury, and repeat. By the age of 23, intense training paired with disordered eating left him weighing just eight stone at 5ft 5in, with bones so brittle that doctors warned his career could be over.

According to BBC Sport, Smith's experience highlights relative energy deficiency in sport (REDs), a syndrome that can impact performance and cause serious health issues if left undiagnosed or untreated. BBC Sport reported that after suffering two stress fractures in four months, Smith sought professional help and received his diagnosis.

While the symptoms of REDs are slightly better documented in women—such as tennis player Emma Navarro recently revealing her diagnosis and decision to step away from competition until 2027, as reported by BBC Sport—men are just as susceptible. BBC Sport noted that due to social stigma and a lack of obvious warning signs, the condition often goes undetected in men, leaving many athletes to suffer in silence.

Background

According to BBC Sport, REDs can cause bone stress injuries, disrupted sleep, fatigue, and low mood. If left untreated, the condition can lead to serious long-term health complications, including osteoporosis, cardiovascular disease, and fertility issues.

Dr Nicky Keay, an expert in hormone health cited by BBC Sport, explained that many of these symptoms stem from hormonal disruption caused by insufficient energy intake. Keay stated that hormones affect every part of the body and require regular feeding through an adequate energy supply, otherwise hormone systems can slow down or shut down completely.

BBC Sport reported that while women have a monthly barometer of hormone health through the menstrual cycle where periods are switched off under REDs, the impact on men is more subtle. According to the report, male athletes experience a drop in testosterone levels, resulting in reduced libido and fatigue.

Why it matters

For sports enthusiasts and athletes, understanding the physiological limits of the human body is essential. The findings reported by BBC Sport demonstrate that high-performance training without proper energy balance carries severe medical risks across both genders, emphasizing the importance of awareness and professional medical support in sports science.