Abstract
Overtraining may be one frequent cause of stagnation or decrease in performance capacity
of athletes. Israel (19) differentiates between addisonoid (parasympathetic) and basedowoid
(sympathetic) overtraining, characterized by inhibition or excitation. We tried to
induce an overtraining syndrome in 8 experienced middle- and long-distance runners,
based on an increase in training volume from an average 85.9 km (week 1) to 115.1
km (week 2) and 143.1 km (week 3) to 174.6 km per week (week 4). The influence of
this training on cardiovascular, metabolic and hormonal parameters was examined with
special respect to plasma and urinary catecholamines. Laboratory testing including
graded treadmill running was performed on the days 0, 14 and 28. Training was held
six days each week, with nearly 30 km per day in the fourth week. A stagnation in
endurance performance capacity (running velocity at the aerobic-anaerobic transition
range) and a decrease in maximum working capacity were observed in 6 and a stagnation
in 2 of the 8 sportsmen, indicated by a decrease in total running distance from 4719
+ 912 m to 4361 + 788 m during incremental treadmill ergometry. The sportsmen could
neither improve nor could they even approximately reach their personal records during
the subsequent competitive season. Subjective complaints, classified on a four-point
scale, increased from 1.2 (week 1) to 3.2 in week 4. Glucose, lactate, ammonia, glycerol,
free fatty acids, albumin, LDL, VLDL cholesterol, hemoglobin level (transient), leukocytes,
and heart rate (before and during exercise) decreased significantly. Urea, creatinine,
uric acid, GOT, GPT, gamma-GT, serum electrolytes (except phosphate and calcium) remained
constant at the measuring times, CPK was elevated. Noradrenaline plasma levels increased
at the same submaximum workload during treadmill ergometry. Basal, nocturnal urinary
catecholamine excretion (dopamine, noradrenaline, adrenaline) fell to 28-30%, the
24-h cortisol excretion to 70% of baseline values. There was a correlation between
the decrease in urinary noradrenaline excretion and the complaint index (r = 0.91;
adrenaline r = 0.79; dopamine r = 0.62, p < 0.10). In our opinion, the increase in
exercise-induced noradrenaline plasma levels during treadmill ergometry combined with
a 70% decrease in basal urinary catecholamine excretion may be of diagnostic relevance
in short-term overtraining. The mosaic of the other findings cited can support the
diagnosis.
Key words
Training - overtraining - metabolism - catecholamines
