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FATIGUE AND IRON DEFICIENCY IN ATHLETES - a patient's
guide
Dr Ruth Highet - Sports Physician
Which athletes are most at risk of fatigue?
Probably the most common non-injury problem that I see
presenting in sports medicine practice and usually several
times a week is the "fatigued athlete".
The sporting background that "the afflicted" athlete/patient
most often comes from is triathlon, multi-sport, cycling
or distance running. Why this is the case is not the subject
of this article. Suffice to say that the potential for athletes
to overtrain in these sports is huge due to the physical
and "time" demands of training intensively in more than
one discipline.
Most sportspeople that I know in the sports of triathlon/multi-sport
are also very goal-driven people. Most are already involved
in or studying towards careers that are also very time-consuming
and there is only "X" number of hours in the day. The aforementioned
athlete may therefore have great difficulty in "fitting
it all in". In struggling to do so, sleep, something every
athlete needs plenty of, is the area where the athlete tries
to make up some time from.
The multi-sport athlete who presents with unexplained
fatigue will often fit into the above basket of simply too
much work/training and not enough rest. However we cannot
make that diagnosis without ruling out some of the medical
causes for fatigue and staleness.
Iron deficiency in athletes
You probably all know that iron deficiency is a common
cause for fatigue and that is easily ruled out by a blood
test. Some of you, particularly women, will have experienced
the symptoms of iron deficiency and will not want to "go
back there again". The rest of this article will discuss
some issues with regard to diagnosis and management of iron
deficiency.
There is considerable debate over appropriate treatment
of iron deficiency so I emphasise that what follows is "my"
approach to assessment and treatment. Other sports medicine
specialists and other doctors might not adopt the same stance
in terms of levels deemed acceptable for iron stores in
the body and also for methods used to restore optimum iron
levels.
My management however of iron deficiency has developed
from dealing with large numbers of iron deficient athletes
(certainly most commonly women runners and triathletes)
over the years who have come to me because they have had
problems with low iron levels affecting their sporting performance.
Many of them have not previously been diagnosed as iron
deficient. A significant number having been diagnosed have
not been able to satisfactorily resolve their problems.
I am not going to go into detail about the biochemistry
of iron in the body - you do not need to know that to understand
my viewpoint.
Iron levels in the body depend on the difference between
intake into the body through the diet, and losses from the
body (blood losses via periods, urine, bowels and sweat
losses). If losses are greater than intake then you are
going to end up iron deficient further down the track. Because
iron is such an important component of haemoglobin (the
molecule that carries oxygen around in the bloodstream)
you can readily understand that low iron levels may result
in low levels of haemoglobin that will affect your aerobic
performance.
What are normal iron levels for athletes?
The contentious area in medical circles is what is normal
and what is low for an athlete - should we use the same
levels as for the sedentary population of what is normal
and abnormal (i.e. low)? I do not believe so.
There is a huge range of "normal " levels. In the ideal
world, where we would all eat diets rich in iron, we would
all absorb the iron well we do take in from our diet and
we wouldn't have excessive blood or other losses of iron,
then we might all be in the normal range AND at our optimum
levels. BUT, the ideal world does not exist. Iron is a very
"poorly" absorbed mineral even in the best absorbers (only
10%).
The only real way to know if your levels are "optimal"
for you (and not just in the "normal range for the general
population") is to have a course of iron therapy with pre
and post blood tests. If you find your haemoglobin (Hb)
count rises from 124 to say 134, with treatment (both these
levels being within the "normal range" for a young woman),
and you find that you feel aerobically much fitter and your
performance is better, then that increment in your blood
count, which is the equivalent of an extra litre of oxygen
carrying capacity, is probably responsible. In the meantime,
your iron "stores" as measured by your "ferritin" levels
may have also increased from 20 to 50, again both in the
"normal" range as quoted by the labs for the general, mostly
sedentary population.
For what its worth, the levels that I use, which are considerably
higher than what the labs use as lower limits of normal
for these tests, are an Hb of 130 and ferritin of 30 for
a female athlete, and an Hb of 140 and a ferritin of 50
in a male athlete. For athletes whose levels are below the
above mentioned, who are struggling to find "their form",
and in whom there is no obvious medical diagnosis to explain
their fatigue, I recommend a trial of iron supplementation.
The aim being to try and get them up to their optimum level
(or see if they are already at their optimum).
Nutrition issues
Dietary assessment is hugely important and this has been
covered in previous issues but to reiterate, a "several
day dietary recall" is useful to see just what the average
daily intake is. Diet alone is pretty slow in resolving
significant iron deficiency so supplements (pills) are usually
necessary to help bring levels up or see an effect more
quickly.
Ideally after achieving optimum levels, the diet should
aim to maintain these improved levels.
Intramuscular iron injections
In some women, who absorb iron even more poorly than most,
and who have a very slow or minimal response to iron medication
by mouth, there is I believe justification for intramuscular
iron injections. Once again this is a contentious issue
medically because there have been no controlled studies
showing that this works better than tablets but anecdotally
there is no doubt in my mind. There are risks with iron
therapy intramuscularly, but these are very rare and far
less common than risks associated with far more frequently
used medications.
I will "not infrequently" use intramuscular iron in athletes,
usually female, who have presented with fatigue, with low
blood counts and iron levels, who have failed on an iron-rich
diet + an iron medication programme to increase their iron
stores and blood counts. It usually results in significant
increments in both scores "quickly" which gives them the
benefit of training at their optimum blood count and iron
levels, and they will quickly tell me whether they feel
any different or not. It then is important to make sure
the improved status is maintained with serial blood testing.
Beware of other causes of fatigue in athletes
Not all fatigue however is iron deficiency. Not infrequently,
athletes presenting with fatigue may have undiagnosed asthma,
underlying viral or another infection they were not aware
about, or other conditions like an overactive or underactive
thyroid, heart disease, high blood pressure, diabetes, kidney
disease, depression or even cancer.
Every athlete presenting with fatigue needs a full work-up
with a full history of their fatigue, clinical examination,
and blood tests before assuming that overtraining is the
culprit - it however often is!
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