physiological functioning. It is underpinned by low energy availability (LEA). LEA is a
mismatch between an athlete’s energy intake and the energy expended in exercise,
leaving inadequate energy to support the functions required by the body to maintain
optimal health and performance (Mountjoy et al, 2018).
LEA forces the body’s systems to adapt to lower energy levels, which compromises and reduces the
energy available to the body for key functions such as bone health, reproduction,
and immunity. This increases the risk of multiple health problems.
The female athlete triad has in recent times more commonly been referred to as
RED-S. There are several reasons for this change including the significant number of
physiological consequences of this condition are not just limited to abnormal
menstrual cycles and bone health and RED-S incorporates these factors. Whilst it is
thought that the incidence of LEA is higher in females than in males (Mountjoy et al,
2018) athletes of either gender can suffer from this condition.
LEA is more common in athletes involved in specific sports. These include:
individuals who participate in sports that are endurance based ie distance running
and triathlon; sports where lean or light body types are often considered good for
performance ie cycling, running, rowing, gymnastics as well as sports where a
weight category is implemented for competition ie weightlifting and combat sports.
There may be practical contributions towards LEA also including inadequate food
availability, food insecurity and lack of financial resources and time for food
preparation. Importantly LEA can occur with any body type, at any body mass and in
both men and women.
Commonly LEA is the result of accidentally not meeting the energy needs of their
sport, exercise activity or daily life. An increase in training volume without increasing
dietary energy intake, a lack of food preparation or eliminating food groups can all
increase your risk of suffering from LEA. A lack of knowledge or understanding of
nutrition, being influenced by the eating habits of others and social media dietary
trends may also contribute. There is a continuum from accidental LEA to disordered
eating where eating patterns are deliberate to result in a set outcome.
One of the significant challenges in diagnosing LEA is the accuracy of self-reported
energy intake. Energy expended, total energy intake over the day, as well as the
frequency of eating throughout the day are all important contributors to the
development of LEA.
Some of the signs to look out for as indications LEA may be present include frequent
or repeated illnesses, recurring injuries that don’t get better eg stress fractures, tired
or not recovering from training, absent or irregular menstrual cycles, poor
concentration, reduced interest and low mood along with underperforming in training
and competition. LEA is not always accompanied by weight loss. Weight is therefore
not a great guide on its own to the presence or absence of LEA.
The hypothalamus and pituitary gland are areas of the brain that produce hormones.
These hormones affect how the ovaries work and are critical in having a normal
menstrual cycle. Altered hormone levels of LH (Leutinising hormone) and FSH
(Follicular stimulating hormone) result in alterations to the menstrual cycle. This may
result in oligomenorrhea (3 – 9 periods per 12 months or the length of a cycle more
than 35 days) or amenorrhea (absence of a menstrual cycle). If either of these
issues are present differential diagnoses such as polycystic ovaries should be ruled
out by physicians prior to LEA being confirmed. The most common cause of
amenorrhea or oligomenorrhea in athletes is functional hypothalamic amenorrhea
(FHA). This is when a woman’s body isn’t producing hormones as expected and
therefore periods are affected. In athletes, this usually results from not having
enough energy intake for the amount of exercise being performed. When athletes
are on the oral contraceptive pill (OCP) this is masked, and LEA is difficult to
diagnose although may be suspected. For this reason, if an athlete is at high risk of
developing LEA alternative contraceptive options should be considered such as an
IUD (intra-uterine device). A regular menstrual cycle in an athlete is a sign of health
and therefore alterations to this must be monitored.
Iron deficiency is often seen in female athletes and can be linked to the cause and
effect of LEA. Growth may be affected in athletes with LEA over prolonged periods of
time during their growth phase. In addition to this there can be effects on the
gastrointestinal, immunological, and cardiovascular systems, as well as
psychological effects. There are reported performance consequences of low energy
availability. There is often a “tipping point” where LEA becomes so significant that
performance is affected. Prior to this, athletes may report a period where
performance remains high although they are in a state of LEA. This may be related
to power to weight ratios for their sport. Unfortunately, once performance is affected
it is a long road back for many of our athletes to return to a healthy state where they
may begin to return to their previous sporting performance. Educating athletes
regarding this can be a challenging task particularly in sports where low body fat is
“idealized” for performance.
Treatment for LEA is multidisciplinary and will involve a doctor and nutritionist along
with the involvement as appropriate of other medical professionals such as a
physiologist and psychologist.
The prevention of LEA includes a well-balanced diet that provides enough energy to
support the demands of exercise and life allowing for optimal health, training
adaptation, recovery and performance. When there is an increase in training volume
or intensity, energy intake should increase to match the increase in energy
expenditure. Education of athletes so they understand the energy value of food and
the demand of exercise ensures they are able to proactively ensure they maintain
appropriate energy intake. Be cautious of information online particularly in social
media and seek help early if there is any alteration in their menstrual cycle.
A monthly barometer of female health
The average age in NZ for females to get their first period is 13 years old. Generally,
within 2 years of onset they should have a regular menstrual cycle. If they do not
have a menstrual cycle by 15 years of age, they have delayed menarche and should
see a Doctor for investigation. Athletes often think that missing a period is normal,
but we know this is not normal nor optimal from a health, recovery, or performance
perspective. Recent research in our elite and development high performance
athletes in NZ suggests up to 50% of athletes have or have had menstrual cycle
dysfunction with over a quarter suffering from one or more stress fractures which is
integrally linked to LEA. Up to ¾ of these athletes also reported pressures felt
around the ideal body image and the issues this presents for the health of them as
the athlete. This research also confirmed some of the previously identified barriers
to preventing LEA such as difficulty communicating with male coaches and support
staff regarding this topic, lack of education regarding women’s health, social media,
and sponsors as specific areas of pressure.
In summary having a regular period is a visible sign of good hormonal health and
energy balance. Having regular periods is a good guide to the readiness for training
and performance. If an athlete’s menstrual cycle has changed or does not fit with
the expected pattern a General practitioner (GP), Sports Doctor or Sport Medical
Director should be consulted.
REMEMBER whilst this article is primarily written about female athletes LEA can occur in both males and females so as medical professionals, we should be aware of the risk factors, the signs and symptoms that may be present and when we need to refer for further investigations.