Losing your menstrual cycle is not healthy. Failing to menstruate for more than six months is unhealthy and should be evaluated by a physician. Athletes often view weight loss and losing their menstrual cycles as synonymous with improved athletic performance, and so they must be warned of the serious health risks of not menstruating — particularly, bone loss. Armed with the latest information and research, the athlete herself may be the first and best line of defense against this condition.