What is Red S?

Red S, or Relative Energy Deficiency in Sport, is a syndrome that occurs when athletes have low energy availability. It impacts both men and women and encompasses a range of medical issues that arise from not consuming enough calories to support both general health and athletic training. The effects of Red S include alterations in various physiological functions and can lead to conditions such as menstrual dysfunction, lowered bone density, and psychological issues. Red S points to broader impacts than the previously known Female Athlete Triad, and recovery from it can take a significant amount of time 1.