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What is low energy availability in athletes

This is an excerpt from Clinical Foundations of Athletic Training and Sports Medicine 2nd Edition by Leamor Kahanov,Ellen K. Payne.

By Ellen K. Payne, PhD, LAT, ATC, EMT and Jennifer Doane, MS, RDN, CSSD, LDN, ATC

ATs may be the first health care providers to recognize and intervene with many nutrition- and dietary-related conditions. Treatment of conditions related to lower energy availability may be beyond your scope of practice, but you should know how to recognize signs and symptoms, make proper referrals, and assist with treatment plans prescribed by the team physician, RD, and other members of the sports medicine team. As with all aspects of sports medicine, the team approach is generally the best.

The conditions discussed in the following sections all relate to inadequate energy balance. Energy balance seems simple on the surface: energy in, energy out. However, maintaining optimal energy balance is a more complex situation because bodies have many adaptations to low energy availability. Although disordered eating patterns definitely influence a person’s dietary intakes, they are not the sole reason that the person may suffer the consequences of low energy availability. It is worth mentioning here that the NATA position statement Preventing, Detecting, and Managing Disordered Eating in Athletes is an evidence-based resource for practicing ATs that still holds some valuable information despite it not being updated since 2008.¹⁴

Inadequate consumption of essential nutrients is a factor in many medical and health-related concerns. Any person performing very strenuous exercise or not consuming adequate calories will be at potential risk for developing low energy availability or a relative energy deficit. The term relative can be used in some cases because it is possible for an athlete to be physically unable to consume adequate calories for his sport, such as in the case of an athlete training for an ultramarathon. Although it might seem obvious, it must be stressed that an energy deficit will have many negative consequences on health and, for athletes, performance.

Female Athlete Triad

The female athlete triad was the first defined condition that could be related to low energy availability. It was first defined as a progression of an energy deficit that leads to menstrual cycle disruption and that may ultimately cause bone mineral losses, stress fractures, or osteoporosis.⁸¹ This triad was made more three-dimensional and expanded so that the sequelae of symptoms are now more of a spectrum related to the variations and degrees of physiological changes occurring. The current recommendations for the triad define variations of low energy intakes versus clinical eating disorders, oligomenorrhea to amenorrhea, and ranges of bone mineral loss across a spectrum (figure 10.3).⁸²

Since a defining characteristic of the female athlete triad is the presence or absence of menstrual cycles, it is relatable only to physically active women. In this population, the development of amenorrhea due to low energy availability enhances the risk of the occurrence of stress fractures. Although stress fractures or low bone mineral density can affect any active person’s sport participation, you should focus on the lifelong effects of the potential development of osteopenia or osteoporosis when discussing the triad with your clients. Your ultimate goal is to promote long-term health and wellness.

Suspicions of the female athlete triad should be part of a differential diagnosis when a menstrual cycle is absent for more than 3 months. Any woman who has experienced disruptions to her menstrual cycles for this magnitude or longer should be evaluated by a health care provider specializing in sports medicine and the female athlete triad.

The goal with any treatment is the resumption of normal menses and thus improved bone mineral density. The two main factors in treatment are increased caloric intake and decreased caloric expenditure through reduced exercise. However, overall treatment goals may also include maintaining adequate body fat stores as well as ensuring a desirable level of daily calcium (between 1,000 and 1,500 mg per day). In view of the multiple conditions present, as well as the potential for a clinical eating disorder, take a team approach to care and work with the team physician, an RD, and a mental health professional.

These screening questions are recommended as part of the sport preparticipation examination:⁸³

• Have you ever had a menstrual period?
• How old were you when you had your first menstrual period?
• When was your most recent menstrual period?
• How many periods have you had in the past 12 months?
• Are you presently taking any hormone replacement (estrogen, progesterone, oral birth control pills)?
• Do you worry about your weight?
• Are you trying to lose or gain weight?
• Has anyone recommended that you gain or lose weight?
• Are you on a special diet?
• Do you avoid certain types of foods or food groups?
• Have you ever had an eating disorder?
• Have you ever had a stress fracture?
• Have you ever been told you have low bone density (osteopenia or osteoporosis)?

Return to play after treatment for the female athlete triad is determined by the treating physician and based on a complex and comprehensive combination of health status, cumulative risk assessment, participation risk, sport, and decision modifiers.^83,84 Work with the treating physician and follow any reported guidelines to help a client return to play.

Relative Energy Deficiency in Sport (RED-S)

Although the female athlete triad first identified the topic of low energy availability, the International Olympic Committee (IOC) recently focused on the effect of low energy availability on a full range of body physiology.⁸⁵ In its consensus statement, the IOC applied the physiological changes related to an energy deficit to all athletes, both male and female. The IOC has made special efforts to identify the female athlete triad as one spoke of the wheel of relative energy deficiency in sport (RED-S). However, RED-S has expanded to include the physiological effects of low energy availability across all body systems (figure 10.4).

For the evaluation of the medical risk of RED-S, the IOC provides a three-level, color-coded system.

1. Green light. The green light factors constitute the lowest risk. When physiological systems are evaluated, this level is determined when a provider’s physical assessment finds healthy eating practices, normal metabolic functions, ideal bone mineral density, and a fully functioning musculoskeletal system.
2. Yellow light. When health risks are determined in an assessment, an athlete may be considered in the zone of yellow light and their sport participation reduced or discontinued until they can achieve markers of optimal health. Some considerations for this level are a significant decrease in body fat percentage, primary amenorrhea, reduced bone mineral density, abnormal lab values for hormone profiles, and physiological effects on the cardiovascular system, such as bradycardia.
3. Red light. The red light level of assessment warrants withholding any athlete from participating in sport until medical clearance is obtained. The presence of a clinical eating disorder, serious medical condition (e.g., abnormal electrocardiogram [ECG]), and hemodynamic instability warrants limiting anyone from sport activity.

Lastly, regardless of status, one large factor to successful treatment is patient compliance. Any noncompliance or lack of progress in treatment should be further evaluated and discontinuation of sport participation considered.

More Excerpts From Clinical Foundations of Athletic Training and Sports Medicine 2nd Edition

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