Revista de Medicina Desportiva (English) September 2018 | Page 16

Rev. Med. Desp. informa, 2018; 9(5):14–16.
Relative Energy Deficiency in
Sports (RED-S)
Dra. Adriana de Sousa Lages 1,2 , Dr. Alexandre Rebelo-Marques 2,3,4 , Dr. Francisco Carrilho 1
1
Endocrinology Resident; Endocrinology, Diabetes and Metabolism Department, Coimbra Hospital and
University Center; 2 Sports and Exercise Physician, Injury Prevention and Performance Unit, Clínica do
Dragão, Espregueira-Mendes Sports Centre – FIFA Medical Centre of Excellence;
3
Head of Department; Endocrinology, Diabetes and Metabolism Department, Coimbra Hospital and
University Center. Portugal
ABSTRACT
The Female Athlete Triad was redefined to Relative Energy Deficiency in Sports to emphasize
that the syndrome affects not only female but all athletes and it is multi-organ condition which
impairs both health and performance status. The signs and symptoms are often subtle, so high level
of suspicion is required to establish an early diagnose. A clinical tool (RED-S CAT) was created to
categorize athletes in three risk levels tailoring those who sports activities should be restricted. The
treatment is based on restoring energy imbalance by improving energy intake, reducing exercise load
or a combination of both strategies.
KEYWORDS
Energy, sport, athlete, endocrinology
Introduction
The Female Athlete Triad was con-
ceptually defined, in 1997, by the
American College Of Sports Medi-
cine (ACSM), as quite frequent con-
dition found on the female athlete,
characterized by food disturbance,
amenorrhea and osteoporosis. 1 In
2007, ACSM redefined this concept
in order to include three interrelated
components: energy availability (EA),
associated or not with the pres-
ence of food disturbance, menstrual
disfunction and bone health. 2 Within
this line, the concept of EA was
introduced as the energy available
for physiological functions, after
the subtraction of the energy spent
in physical training, from the total
energy obtained through food intake.
It is desirable a balance between
ingestion and energy expenditure, in
order to optimize the different basal
physiological functions, including
growth and development (Figure
1). 3,4 The decrease of EA represents
the cornerstone of the metabolic
consequences associated with
Female Athlete Triad (menstrual
dysfunction and bone health).
In 2014, the International Olympic
Committee (IOC) defined a more
comprehensive concept of Relative
Energy Deficiency in Sports (RED-
S) emphasizing both the inclusion
of all athletes (not only female),
14 september 2018 www.revdesportiva.pt
and the definition as a multi-organ
condition, amplifying the dimension
of the problem beyond the “triad”
perspective. The proposal was to
include ten distinct areas (menstrual
function, bone, endocrine, metabolic,
hematologic, growth and develop-
ment, physiological, cardiovascular,
gastrointestinal and immunological)
and ten consequences regarding the
athlete’s performance (less resist-
ance, a higher risk
of injury, deficient
training response,
lower capacity of
judgment and cog-
nition, condition-
ing of coordination
and concentra-
tion, irritability,
depression, lower
glycogen reserves
and lower muscle
strength). 5-8
It is emphasized
that the psycho-
logical component
has the particu-
larity of causing,
precede or be the
result of RED-S. 9
The suppres-
sive impact over
the immuno-
logical function is represented by a
deficient type 1 immune response,
which is supported by the evidence
of a higher prevalence of infections,
mainly viral intercurrences, during
competitions (especially pulmonary
and gastrointestinal diseases). 10-13
Traditionally, it is well described
the effect of intensive exercise pro-
grams, a low percentage of body-fat
and low body-weight on the anterior
pituitary function, mainly over the
gonadal function, which has a direct
suppressive action on bone anabolic
function. 2,14 An EA lower than 30
Kcal/kg fat-free mass was associated
to disruption of the possibility of the
luteinizing hormone (LH), to lower
levels of insulin, triiodothyronine
(T3), growth hormone (GH), insulin-
like growth factor (IGF-1) and leptin,
as well as to the increased secretion
of cortisol and beta-hydroxybu-
tyrate, regardless of sports prac-
tice. 15,16 On the other hand, a food
intake lower or equal to 45Kcal/Kg
fat-free mass/day indicates, proxi-
mally, a low EA for adolescents and
young adults, especially for female
athletes. 17-20
The association between a sus-
tained reduced caloric intake and
menstrual dysfunction can assume
different clinical spectra: irregular
menstrual periods (oligomenorrhea
–interval between two menstrual
cycles greater than 37 days but less
than 90 days) up to amenorrhea
(permanent or transient absence
Figura 1 – Consequências para a saúde
do Défice Energético Relativo no Des-
porto (adaptado de 4 )