RED-S CAT™

Relative Energy Deﬁ ciency in Sport (RED-S)
Clinical Assessment Tool (CAT)

for use by medical professionals only

name

Date :

examiner:

ReD-S may also affect athlete sport performance. the potential effects of ReD-S on
sport performance are illustrated in figure 2:

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Decreased
endurance
performance

Decreased
muscle
strength

Increased
injury
risk

Decreased
glycogen
stores

Depression

Triad

Decreased
training
response

Impaired
judgement

Irritability

Decreased
coordination

Decreased
concentration

Screening for RED-S
the screening and diagnosis of ReD-S is challenging, as symptomatology can be sub-
tle. a special focus on the athlete at risk is needed. although any athlete can suffer
from ReD-S, those at particular risk are those in judged sports with an emphasis on
the aesthetic or appearance, weight category sports, and endurance sports. early
detection is of importance to maintain and improve performance and prevent long-
term health consequences.

Screening for ReD-S can be undertaken as part of an annual periodic Health exam-
ination and when an athlete presents with Disordered eating (De) / eating Disorders
(eD), weight loss, lack of normal growth and development, endocrine dysfunction,
recurrent  injuries  and  illnesses,  decreased  performance / performance  variability  or
mood changes.

What is the RED-S CAT?

the  ReD-S  cat  is  a  clinical  assessment  tool  for  the  evaluation  of  athletes / active
individuals suspected of having relative energy defi ciency and for guiding return to
play decisions. the ReD-S cat is designed for use by a medical professional in the
clinical evaluation and management of athletes with this syndrome. the ReD-S cat
is based on the ioc consensus Statement on ReD-S, 2014.1

this  tool  may  be  freely  copied  in  its  current  form  for  use  by  sport  organizations
and the athlete medical team entourage. alterations to the tool or reproduction for
publication purposes require permission from the international olympic committee.

NOTE: the diagnosis of ReD-S is a medical diagnosis to be made by a trained health
care professional. clinical management and return to play decisions for athletes with
ReD-S should occur under the guidance of an experienced sports medicine team.

What is Relative Energy Defi ciency in Sport?
The syndrome of RED-S refers to impaired physiological functioning caused
by relative energy defi ciency, and includes but is not limited to impairments
of metabolic rate, menstrual function, bone health, immunity, protein syn-
thesis, and cardiovascular health.

the cause of ReD-S is the scenario termed “low energy availability”, where an in-
dividual’s  dietary  energy  intake  is  insuffi cient  to  support  the  energy  expenditure
required for health, function, and daily living, once the cost of exercise and sporting
activities is taken into account.

the potential health consequences of ReD-S are depicted in the ReD-S conceptual
model (See figure 1). psychological problems can be both the result of and the cause
of ReD-S.

Immuno-
logical

Gastro-
intestinal

Menstrual
Function

figure 2

TRIAD

Bone
health

Endocrine

Growth +
develo-
pement

Metabolic

Hermato-
logical

Cardio-
vascular

Psycho-
logical

figure 1

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Br J Sports Med 2015;49:421–423.

doi:10.1136/bjsports-2014-094559

RED-S Risk Assessment Model for sport participation
this model can be incorporated into the periodic Health examination. Depending on
the findings on history and physical examination, the athlete is classified into one of
the 3 following categories: “Red Light”: High risk, “Yellow Light”: moderate risk,
“green Light”: low Risk.

HIgH RISK:
NO START
RED LIgHT

MODERATE RISK:
CAUTION
YELLOW LIgHT

LOW RISK:
gREEN LIgHT

 - anorexia nervosa and other
serious eating disorders
 - other serious medical

 - prolonged abnormally low
% body fat measured by
DXa* or anthropometry

(psychological and physio-
logical) conditions related
to low energy availability

 - Substantial weight loss
(5 –  10 % body mass in
one month)

 - Use of extreme weight

loss techniques leading to
dehydration induced hemo-
dynamic instability and other
life threatening conditions.

 - attenuation of expected
growth and development
in adolescent athlete

 - appropriate

physique that
is managed
without undue
stress or un-
healthy diet /
exercise strategies

 - low **ea of prolonged
and / or severe nature

 - abnormal menstrual cycle:
functional hypothalamic
amenorrhea > 3 months
 - no menarche by age 15 y

in females

 - Healthy eating
habits with
appropriate ea

 - Healthy function-
ing endocrine
system

 - Reduced bone mineral

 - Healthy bone

density (either in compari-
son to prior DXa or
Z-score < -1 SD).

 - History of 1 or more stress
fractures associated with
hormonal / menstrual
dysfunction and / or low ea

mineral density
as expected for
sport, age and
ethnicity
 - Healthy

musculoskeletal
system

 - athletes with physical /
psychological compli-
cations related to low
ea+ / -disordered eating;
 - Diagnostic testing abnor-
malities related to low ea
+ / -disordered eating

 - prolonged relative energy

deficiency

 - Disordered eating behavior
negatively affecting other
team members

 - lack of progress in
treatment and / or
non-compliance

 - Severe ecg abnormalities

(i.e. bradycardia)

* dual energy X-ray absorptiometry

**ea: energy availability = energy intake – energy cost of exercise
    (additional energy expended in undertaking exercise).

NOTES on diagnostic tools for Low EA:
although low ea is a key factor in ReD-S, at the present time there is no standardised
protocol for undertaking an assessment of ea in free-living athletes. Some sports
nutrition experts may have developed tools to monitor ea in which they have con-
fidence,  and  may  use  these  to  screen  for  problems  or  guide  dietary  counselling.
However, a universal recommendation to measure ea is unwise in the absence of a
protocol that is sensitive, reliable, time-efficient and cost-effective.

Sport Participation based on Risk Category

“High Risk - Red Light”: no clearance for sport participation.
Due  to  the  severity  of  his / her  clinical  presentation,  sport  participation  may  pose
serious jeopardy to his / her health and may also distract the athlete from devoting
the attention needed for treatment and recovery.
“Moderate Risk -Yellow Light”: cleared for sport participation only with super-
vised participation and a medical treatment plan.
Re-evaluation  of  the  athlete’s  risk  assessment  should  occur  at  regular  intervals  of
1 – 3 months depending on the clinical scenario to assess compliance and to detect
changes in clinical status.
“Low Risk – Green Light”: full sport participation.

Treatment of Relative Energy Deficiency in Sport (RED-S)
athletes  categorized  in  the  red  light  and  yellow  light  zones  should  receive  medi-
cal evaluation and treatment. the treatment of ReD-S should be undertaken by a
team of health professionals including a sports medicine physician, sports dietician,
exercise  physiologist,  athletic  therapist  or  trainer,  sports  psychologist / sports  psy-
chiatrist  as  needed.  Patient  confidentiality  must  be  maintained.  Treatment  should
focus  on  correcting  the  relative  energy  deficit  through  increasing  energy  intake
and / or decreasing energy output. intake of nutrients and other vitamins should fol-
low established guidelines. Repeat assessment of BmD should occur at intervals of
6 – 12 months, depending on clinical presentation and initial values.

the use of an athlete contract is also recommended. (See Appendix)

Relative Energy Deficiency in Sport (RED-S) risk
assessment decision making steps for determining
readiness for returning to play
prior to returning an athlete to sport / physical activity following time away for ReD-S
treatment,  an  assessment  of  the  athlete’s  health  and  the  requirements  of  his / her
sport should be undertaken following the step-wise approach:

STEPS

STEP 1
evaluation of
Health Status

RISK
MODIFIERS

meDical
factoRS

CRITERIA

RED-S SPECIFIC
CRITERIA

 - patient Demo-

graphics
 - Symptoms
 - medical History
 - Signs
 - Diagnostic tests
 - psychological

Health
 - potential

Seriousness

 - age, sex
 - See yellow light column
in ReD-S Risk assessment
model

 - Recurrent dieting,

menstrual health, bone
health

 - Weight loss / fluctuations,

weakness

 - Hormones, electrolytes,
electrocardiogram, DXa

 - Depression, anxiety,
disordered eating /
eating disorder

 - abnormal hormonal and

metabolic function
 - cardiac arrhythmia
 - Stress fracture

 - Weight sensitive,
leanness sport

 - individual vs. team sport
 - elite vs. recreational

SpoRt RiSK
moDifieRS

 - type of Sport
 - position played
 - competitive level

STEP 2
evaluation of
participation
Risk

STEP 3
Decision
Modification

DeciSion
moDifieRS

 - timing and

Season

 - in / out of season, travel,
environmental factors

 - pressure from

 - mental readiness to

athlete

compete

 - external pressure
 - Conflict of Interest
 - fear of litigation

 - coach, team owner,

athlete family, sponsors
support

 - if restricted from

competition

Return to Play Model

following clinical reassessment utilizing the 3 step evaluation outlined above, ath-
letes can be re-classified into the “High Risk – Red light”, “moderate Risk – yellow
light” or “low Risk – green light” categories. the ReD-S Risk assessment model is
adapted to aid clinicians’ decision making for determining an athlete’s readiness to
return to sport / physical activity.

the ReD-S Return to Play Model outlines the sport activity recommended for each
risk category.

HIgH RISK
RED LIgHT

MODERATE RISK
YELLOW LIgHT

LOW RISK
gREEN LIgHT

 - no competition
 - no training
 - Use of written contract

 - may train as long as

 - full sport participation

he / she is following the
treatment plan

 - may compete once

medically cleared under
supervision

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Br J Sports Med 2015;49:421–423.

doi:10.1136/bjsports-2014-094559

APPENDIx

Relative Energy Deficiency in Sport (RED-S) Treatment Contract

ReD-S treatment contract for

Multidisciplinary Team:

 ■ (physician)

 ■ (psychotherapist / psychiatrist)

 ■ (exercise physiologist)

 ■ (Dietitian)

 ■ (other)

Requirements

meet with:

 ■ the psychotherapist at intervals recommended by the health professional treatment team

 ■ the dietitian at intervals recommended by the health professional treatment team

 ■ the physician at intervals recommended by the health professional treatment team

 ■ follow daily meal plan developed by the health professional treatment team

 ■ follow the adapted training plan developed by the health professional treatment team

 ■ if underweight, weight gain expected to be

  kg per week / weight stable within week

 ■ if underweight, must achieve minimal acceptable body weight / fat of

  kg / percent by

 ■ Regular weigh-in at the following time intervals of

  week (s)

 ■ after this date,

 ■  other

(dd / mm / yyyy), must maintain weight and % fat at or above minimal acceptable body weight/fat mass of

(kg / %)

if ALL requirements are met and the eating behavior (and other severe conditions) are normalized the team physician will decide if cleared for competition.

i,

  have read this contract and all of my questions were answered.

athlete name

team physician name

References

  athlete Signature

  team physician Signature

  Date

  Date

mountjoy m, Sundgot-Borgen J, Burke l, et al. ioc consensus Statement. Beyond the triad – ReD-S in sport. Br J Sports med. 2014; 48: 491-7.

Contributing Authors

Margo Mountjoy (CAN)

ioc medical commission games group
mcmaster University medical School

Jorunn Sundgot-Borgen (NOR)  Department of Sports medicine

the norwegian School of Sport Sciences

Louise Burke (AUS)

Sports nutrition, australian institute of Sport

Susan Carter (USA)

University of northern colorado
University of colorado medical School

Naama Constantini (ISR)

orthopedic Department, Hadassah-Hebrew University medical center

Constance Lebrun (CAN)

Department of family medicine,
faculty of medicine & Dentistry, and glen Sather Sports medicine clinic, University of alberta

Nanna Meyer (USA)

University of colorado, Health Sciences Department

Roberta Sherman (USA)

the victory program at mccallum place

Kathrin Steffen (NOR)

Department of Sports medicine,
the norwegian School of Sport Sciences

Richard Budgett (SUI)

IOC Medical and Scientific Department

Arne Ljungqvist (SWE)

ioc medical commission

Kathryn Ackerman (USA)

Divisions of Sports medicine and endocrinology,
Boston children’s Hospital, neuroendocrine Unit
massachusetts general Hospital, Harvard medical School

Br J Sports Med 2015;49:421–423.

doi:10.1136/bjsports-2014-094559

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