Overtraining Syndrome
By Kim Smith
Kimberly Smith is a certified personal trainer and aerobics instructor. She holds a Masters degree from Brandeis University
and is currently studying at New York Chiropractic College. This is a cogent overview of the basic types of overtraining.
Overtraining syndrome (OTS) is an illness rooted in the best of intentions; it develops due
to overzealousness on the part of athletes, their parents, and even their trainers. More than simple "bum-out,"
OTS is a set of metabolic, hormonal, and immunological changes resulting from autonomic imbalances due to inadequate rest
periods. "Overtraining is not exhaustion," argues Dr. Alfonx Kereszty, "... [it] represents the result of a
perturbed nervous system,".
The consequences for an athlete are myriad. The body begins to undergo
a "fundamental change in the way [it] chemically responds to the physical stress of workouts". Although it is most
frequently seen in highly competitive athletes, overtraining can occur in any individual who engages in an improperly patterned,
or periodized, long-term workout schedule.
There are two distinct forms of this illness: one that
results from chronic over-stimulation of the sympathetic nervous system (the so-called "fight or flight" system)
and another caused by chronic over-stimulation of the parasympathetic nervous system (the "rest and digest" system).
The form of the disease that a particular athlete develops depends on the type of training in which he is involved. Sprinting-type
athletes develop the sympathetic, "classical" (sometimes called "Basedowoid"), form of the syndrome, while
endurance-type athletes are prone to the more common parasympathetic, "modern" (sometimes called" Addisonoid"),
form. This discussion walks the reader through the metabolic, endocrine, and immune system changes that occur in the body
of an athlete who has come down with either form of OTS.
METABOLIC CHANGES
An overtrained athlete whose workouts focus
on sprinting-type, burst-of-energy activities has likely gotten" stuck" in sympathetic ("fight or flight")
excitation. This has profound consequences for his cellular metabolism. Sympathetic signals keep telling his cells to undergo
catabolism (breakdown) and forego anabolism (synthesis); these signals also impede replenishment of the nitrogen supplies
he needs for amino acid synthesis. The upshot is that his body loses much of its natural ability to regenerate, adapt, and
improve after exercise-so his health and performance begin to deteriorate.
Sympathetically overtrained
athletes will usually exhibit increased resting heart rates and basal metabolic rates. "Most highly trained athletes
have heart rates in the 50-60 beat per minute range," writes Dr. Mac Knight. However, a Basedowoid-type OTS patient,
although highly conditioned, may have a resting heart rate of 80 bpm or more. He may also report sweating, nervous symptoms,
irritability, restlessness, and insomnia. These are all direct consequences of the bombardment of sympathetic signaling.
An athlete with parasympathetic OTS, on the other hand, has undergone so much endurance training that
he/ she exists in a state of ongoing metabolic suppression. The overactive parasympathetic system tells his body cells to
undergo lots of anabolism (synthesis) and suppress catabolism (breakdown), so the tissues, too, begin to lose some of their
ability to handle incoming chemicals properly.
Overwhelming parasympathetic signals effectively preempt
the sympathetic "fight or flight" signals that should allow for bursts of strength and energy. This leads to worsening
athletic performance and quicker exhaustion during training (8). These parasympathetic signals also decrease the athletes'
heart rate and basal metabolic rate. The athlete may show signs of anemia, chronic fatigue, digestive disturbances and depression,
and report that he tires more quickly during once-manageable workouts.
HORMONAL
CHANGES
Chronic over
stimulation of one autonomic system or the other also directly affects the endocrine (hormonal) system. That's because, among
other targets, autonomic processes stimulate the release of hormones useful to their purpose (Le., hormones that promote "fight
or flight" or hormones that promote "rest and digest"). Patients in a chronic state of sympathetic over-stimulation
show sustained levels of hormones that are supposed to be secreted transiently in response to the sympathetic impulses.
"There is no doubt that overtraining can be associated with increased levels of cortisol and thyroid hormones and tends
to decrease testosterone," writes David Keast. In fact, "a reduced ratio of free testosterone to cortisol has been
suggested as an indicator of [sympathetic-type] overtraining". The psychological consequences of these hormonal imbalances
include anxiety, loss of appetite, restlessness, insomnia, weight loss, and decreased libido.
Athletes
whose bodies are chronically parasympathetically over-stimulated exhibit a different set of hormonal changes. The most important
of these include lowered levels of cortisol, thyroid, and catecholamines hormones. As a result, Addisonoid-type OTS patients
may complain of depression, chronic fatigue, sleep disturbances and loss of motivation. The graph above describes in visual
terms the psychological impact of the hormonal changes in parasympathetic-type OTS.
IMMUNOLOGICAL
CHANGES
Any imbalance
of the autonomic system, whether sympathetic or parasympathetic, invariably impacts immunity. Patients with both types of
OTS are known to exhibit decreased numbers of the cells in the body that are responsible for normal immunity (including lymphocytes,
NK [natural killer] cells, neutrophils, and eosinophils), and, as a result, exhibit variations in lymphocyte balance and reduced
mitogen responses. The question is, how do autonomic imbalances cause these immunological compromises?
There is considerable controversy surrounding that particular question. Experts have proposed different mechanisms as to how
and why OTS athletes get sick more often, and no single accepted answer exists. One possibility is the connection between
the autonomic system and the endocrine (hormonal) system. Since hormone levels have a direct impact on immunity, altering
their delicate balance through sympathetic or parasympathetic over-stimulation can make patients more susceptible to infection.
For example, since the hormone cortisol has a particularly potent inhibitory effect on the immune system, increased levels
of cortisol may cause patients with sympathetic-type OTS to become immuno-compromised.
Another proposed
explanation as to why patients with OTS tend to get sick is the autonomic system's impact on cellular metabolism. After all,
the products of cellular metabolism are the fuels that drive all body systems, including the immune system. An athlete needs
to be able to break down (catabolize) incoming chemicals and use them to build up (anabolize) the fuels that his body needs
to fight illnesses. Since an improperly balanced autonomic system may lead to trouble with catabolism (in sympathetic OTS)
or with anabolism (in parasympathetic OTS), the body can find itself with a shortage of fuel.
For
example, in a healthy person, skeletal muscle synthesizes glutamine after exercise; among its many functions, glutamine allows
T-Iymphocytes to destroy any infectious microbes that may have entered the body. In a person with chronic sympathetic over-stimulation,
anabolism of any sort is difficult, so the muscles cannot make enough glutamine to fuel the T-Iymphocytes.
Many specific mechanisms of this sort have been proposed; none have been reliably substantiated. Whatever the reason, though,
"there have been reports of increased... upper respiratory tract [infections], [and] increases in allergies to environmental
and food allergies at the gut level" in overtrained athletes with both forms of the syndrome.
CONCLUSION
Fortunately, OTS is a completely reversible disease unless the athlete resumes previous training levels before healing has
been accomplished. Although the physiological mechanisms of OTS are complex, and even controversial, the treatment is generally
straightforward: the patient needs to switch to a very light exercise routine while his/her body recovers from the imbalance
for at least two to six weeks (the exact duration of rest depends on the individual and the progression of the syndrome).
Rest is by far the most important healing tool; however, there are also some nutritional and therapeutic
protocols that can help speed an overtrained athlete's recovery. Vitamin and mineral supplementation is useful for both types
of the syndrome. A sympathetic-type OTS patient may benefit from a diet rich in alkaline foods (milk, fruit, vegetables) and
complex carbohydrates to stimulate the appetite: he should avoid stimulants like coffee and alcohol.
Helpful therapies include water immersion (warm baths relax the muscles), light massage, and light, rhythmic exercises. If
the OTS is parasympathetic-type, the patient's diet should favor acidic foods like cheese, meat, and eggs, and it should be
rich in protein. Therapies include deep massage and immersion in water of alternating temperatures (a warm sauna followed
by a cold shower).
All told, the human body's ability to recover from this syndrome is impressive.
Despite the cumulative, systemic effects of truly vigorous overuse, it remains capable of returning to a normal, healthy state
with little outside assistance. All an athlete really needs to bounce back from OTS is some well-earned vacation time.
FROM: TRACK COACH 177
