Relative Energy Deficiency in Sport (REDs) affects male athletes, causing bone stress injuries and fatigue. Despite its prevalence, it remains under-reported. Dr. Nicky Keay highlights hormonal disruption as a cause.

The 'lighter is faster' mindset in sports has led many athletes to under-fuel, risking long-term health. Olympic triathlete Jonny Brownlee admits to past mistakes. Education and awareness are crucial to combat REDs. Read more everyday miles coverage.

Project REDs, founded by former GB runner Pippa Woolven, offers resources for athletes. Dr. Keay sees more men seeking help, often in poor health. Education and screenings are vital to prevent REDs and promote athlete health. Related: Ozone Exposure Affects Endurance Athletes' Performance.

This original Runner World brief is based on reporting from BBC Sport Athletics. Visit the source for its complete reporting, context and any later corrections.