Athlete’s Energy Crisis: Understanding REDs and Its Impact

Relative Energy Deficiency in Sport (REDs) describes a syndrome of poor health and declining athletic performance that occurs when athletes do not consume enough calories to meet the energy demands of their daily lives and training1. This energy deficit, known as low energy availability, can become serious if an athlete continues to train without adequate refueling, ultimately impacting their endurance, strength, overall health, and well-being.

How REDs Differs from Related Conditions

REDs is a broader concept that evolved from and encompasses the female athlete triad.

• The female athlete triad describes three interconnected conditions: disordered eating, irregular menstruation, and bone loss.
• The International Olympic Committee expanded this concept in 2014 with the term REDs to cover the broader consequences of chronic low energy availability on an athlete’s health and performance, and to acknowledge that any athlete, regardless of gender, can experience this syndrome. While REDs can involve disordered eating, it is not synonymous with an eating disorder.

Who is Most Susceptible to REDs?

REDs can affect athletes of any gender and ability level1. However, several factors and types of athletes increase susceptibility:

• Athletes in Sports Emphasizing a Lean Physique:
  • Sports that link athletic success to a thin body type, such as figure skating, gymnastics, and diving, can increase an athlete’s risk of REDs by promoting unrealistic body ideals.
  • Sports with frequent weigh-ins, like lightweight rowing and wrestling, also heighten the risk as athletes may severely restrict calories to make weight.
  • Endurance athletes, such as marathoners and cyclists, experience REDs at high rates.
  • Lionel Sanders, an Ironman athlete, believes he has every symptom of REDs due to chronic under-fueling relative to his training demands5. Cross-country skiing and biathlon athletes, which are low-impact endurance sports, are also highlighted as susceptible to poor bone health related to REDs.
• Athletes with Low Body Fat:
  • When an athlete’s body fat becomes very low, their body may enter a “survival state” where it slows down its basal metabolic rate to prevent further weight loss, even if they are in an energy deficiency. Lionel Sanders, for example, noted he was at the lowest body fat percentage of his life (around 4-5% historically, and currently weighing 157-158 lbs compared to 165-166 lbs when he felt “ferocious”), and despite consuming what he thought was sufficient, he was still in an energy deficit.
  • This is often a misconception about REDs, as weight loss is not always a primary symptom, especially for those with already low body fat, because the body tries to preserve it.
• Adolescent Athletes:
  • Adolescent endurance athletes are particularly vulnerable due to the high training volume combined with the additional energy needs for growth, development, and puberty.
  • A longitudinal study on male adolescent endurance athletes found that more than one-third had poor bone health in their lumbar spine at baseline, and most either lost or did not achieve the expected pubertal bone mineral accrual over a three-year period, despite overall performance improvements and no other clear REDs indicators like low energy availability or disordered eating behaviors…. This highlights the critical importance of early detection of impaired bone health in this population.
• Training and Team Culture:
  • A team culture that promotes body shaming or emphasizes “winning at all costs” can pressure athletes to over-exercise and under-fuel, leading them to ignore their body’s signals15.
  • Low energy availability can initially lead to short-term performance improvements, but this is temporary, and as REDs progresses, it depletes performance, leading some athletes to train even harder without adequate fuel or rest, exacerbating the problem16.
• Lack of Awareness and Misconceptions:
  • Athletes, coaches, and even medical professionals may misunderstand REDs, sometimes lumping it with eating disorders, leading to a lack of attention to its non-weight-loss manifestations417. Lionel Sanders admitted his “complete ignorance” about REDs, thinking it didn’t apply to him because he didn’t have disordered eating, despite experiencing numerous symptoms. He also noted that “cleaning up” his diet by eating healthier foods inadvertently reduced his caloric intake even further because he didn’t compensate with calorie-dense foods.
• Warning Signs and Symptoms:
  • Individuals experiencing frequent stress fractures are highly susceptible5. Lionel Sanders had two stress fractures within 13 months, in addition to a rib stress fracture a year prior and a sacral stress fracture, which he learned is often related to diet.
  • Other symptoms include fatigue, frequent illness, decreased testosterone, problems with reproductive health (e.g., low libido or erectile dysfunction in men, irregular periods in women), poor sleep, and impaired immune function4…. Lionel Sanders experienced a significant drop in testosterone, frequent illnesses (10 times in 15 months), and loss of nocturnal erections, which he learned is an early sign for men equivalent to a woman losing menstruation.