Lecture Notes: Relative Energy Deficiency Syndrome (REDS)

What is Relative Energy Deficiency Syndrome (REDS)?

Epidemiology

  • Flatt et al. (2021) examined 3509 competitive athletes and reported:

    • 74% reported binge eating.

    • 26% reported vomiting.

    • 50% reported fasting.

  • Ravi et al. (2021) studied 846 female athletes across 67 sports and found:

    • 25% reported restrictive eating.

    • 18% reported eating disorders.

  • Beals and Manore (2000) found that 75% of participants in endurance sports had lower body satisfaction and eating disorder symptoms.

  • Fochesato et al. (2021) reported lower body satisfaction (30%) and eating disorder behaviors (16%) in female volleyball athletes.

Why are Athletes at Risk of Low Energy Availability?

  • Restricted eating, disordered eating, or overreaching.

  • Eating habits of athletes/dancers are often different from non-athletes and closer to the spectrum of eating disorders.

  • Important to consider the athlete personality type (perfectionism, highly driven, praised for potential and for obsessive nature, rigidity, attention to detail).

  • Pressure to look a certain way, eat certain things, and do certain things.

  • However, not always linked to eating disorder via unintentional under fueling.

Consider these examples of harmful comments:

  • "You don’t look like a runner, aren’t you a bit big?”

  • “Good, now you have had a stress fracture, it means you are a real athlete”

  • “You need to lose more weight, try and just eat carrots”

  • “Are you sure you should be eating that?”

Disordered Eating

  • Multifactorial, influenced by culture, family, genetics, biochemistry, personality, psychological distress, pressure to lose weight, overtraining, and injury.

  • Incidence varies considerably between sports:

    • 13% in adolescent and 20% in adult elite female athletes.

    • 3% in adolescent and 8% in adult elite male athletes.

Female Athlete Triad

  • Previously focused on energy availability, irregular menstrual function, and bone health in women (IOC statement 2005).

  • Key in highlighting the epidemic of low energy availability on health, bodily function, and athletic performance.

  • Athletes in sports (track and field, cross country running, cycling, wrestling, gymnastics, rowing, and synchronized swimming) which traditionally focus on leanness as key maximizing power-to-body- mass ratio to improve performance are often at greater risk.

Disordered Eating (cont.)

  • Restrictive dieting often turns into chronic dieting, then into disordered eating, which refers to various abnormal eating behaviors, such as:

    • Restrictive eating

    • Fasting

    • Frequently skipping meals

    • Taking diet pills, laxatives, diuretics, or enemas

    • Overeating

    • Purging

    • Clinical eating disorders, such as bulimia nervosa, anorexia nervosa, binge- eating disorder, and other specified feeding and eating disorders.

Development of RED-S

  • Energy deficiency in sport is not just a triad (bone health, menstrual function and energy availability) but a clinical phenomenon.

  • We need to consider how low energy availability affects:

    • Physiological function (metabolic rate, menstrual function, bone health, immunity, protein synthesis, cardiovascular function)

    • Psychological health

    • It affects men and women

  • Energy availability is defined as:Energy availability = Energy intake – Energy cost of exercise relative to fat free mass

Low Energy Availability

  • Energy availability = Energy intake – Energy cost of exercise relative to fat free mass

  • Complex relationship between reduction in energy availability and disruption of hormones, bone formation markers, as these and the threshold for them all vary in different people.

  • Resting metabolic rate is underestimated in small statured people.

  • Other factors such as psychological distress and variation between days in energy deficiency interact with each other and can also influence the effect of low energy availability.

Health Consequences of RED-S

  • Unfavorable lipid profiles and endothelial dysfunction increasing CV risk.

  • Muscle protein synthesis is reduced.

  • Reduction in glucose utilisation causes mobilisation of fat stores, metabolic rate slows, and decreased production of growth hormone.

  • Disruption of oestrogen (to increase uptake of Ca^{2+} into blood and deposition into bone) and progesterone (to aid oestrogen function) will disrupt bone formation = increased risk of stress fractures.

  • Primary amenorrhoea = no menses by 15 years.

  • Secondary amenorrhoea = none 3 consecutive months post-menarche (69% dancers, 65% long distance runners).

  • Anaemia

  • Risk of infections and illness

Performance Consequences of RED-S

  • Decreased glycogen stores

  • Depression

  • Decreased muscle strength

  • Decreased endurance performance

  • Increased injury risk

  • Irritability

  • Decreased coordination

  • Decreased concentration

  • Decreased training response

  • Impaired judgement

Screening and Diagnosis

  • Conduct a thorough health examination.

  • Capture factors related to weight and weight loss, lack of normal growth, menstrual function, recurrent illness and injuries, decreased performance, and mood changes.

  • However:

    • No effective or validated tool for screening athletes at risk of RED-S (more research is needed!).

    • The “brief eating disorder in athletes questionnaire” is validated and results suggest it can distinguish those athletes with/without low energy availability.

    • All tools are not designed for men.

    • No standard guidelines to determine low energy availability.

Treatment and Management Strategies

  • Increase in energy intake (increase by 300-600 Kcal per day, but spread over the day, around exercise sessions, varied dietary composition, reduce food related stress).

  • Address underlying problems.

  • Modification of training.

  • Oral contraceptives not advised as can mask underlying menstrual problems.

  • Improving bone health can be challenging because some changes are irreversible, but increase in energy availability, calcium, vitamin D, and resistance training can help.

  • Mental health support.

Returning to Exercise: Risk Assessment

  • High risk (red light): No start

    • Anorexia nervosa and other serious eating disorders

    • Other serious medical (psychological and physiological) conditions related to low energy availability

    • Extreme weight loss techniques leading to dehydration induced haemodynamic instability and other life-threatening conditions

  • Moderate risk (yellow light): Caution

    • Prolonged abnormally low % body fat measured by DXA or anthropometry using ISAK or non-ISAK approaches

    • Substantial weight loss (5-10% body mass in 1 month)

    • Attenuation of expected growth and development in adolescent athlete

    • Abnormal menstrual cycle: FHA amenorrhoea >6 months, Menarche >16 years

    • Abnormal hormonal profile in men

    • Reduced BMD (either from last measurement or Z-score < -1 SD).

    • History of 1 or more stress fractures associated with hormonal/menstrual dysfunction and/or low EA

    • Athletes with physical/psychological complications related to low EA/ disordered eating - ECG abnormalities- Laboratory abnormalities

    • Prolonged relative energy deficiency

    • Disordered eating behaviour negatively affecting other team members

    • Lack of progress in treatment and/or non-compliance

  • Low risk (green light):

    • Healthy eating habits with appropriate energy availability

    • Normal hormonal and metabolic function

    • Healthy BMD as expected for sport, age and ethnicity

    • Healthy musculoskeletal system

Returning to Exercise: Return-to-Play Model

  • High risk (red light):

    • No competition

    • Supervised training allowed when medically cleared for adapted training

    • Use of written contract

  • Moderate risk (yellow light):

    • May compete once medically cleared under supervision

    • May train as long as is following the treatment plan

  • Low risk (green light):

    • Full sport participation

Returning to Exercise: Decision-Based Return-to-Play Model

  • Steps:

    • Step 1: Medical factors (Evaluation of health status)

    • Step 2: Sport risk modifiers (Evaluation of participation risk)

    • Step 3: Decision modification (Decision modifiers)

  • Criteria:

    • Patient demographics

    • Symptoms

    • Medical history

    • Signs

    • Laboratory tests

    • Psychological health

  • Risk Modifiers:

    • Potential seriousness

    • Type of sport

    • Position played

    • Competitive level

    • Timing and season

Revision Questions

  • What does RED-S stand for?

  • Name 3 symptoms and 3 performance consequences of RED-S?

  • How does RED-S differ from the female athlete triad, which one is better and why?