Egzersiz Çevrimiçi Dergi - Süleyman Demirel Üniversitesi

egzersiz 2007 • Sayı 2 • No: 1
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al. 2000). Also used as an indicator of oxidative
stress is total antioxidant capacity. There have
been studies for exercices at different types and
intensities (Defaux et al. 1997). For acut exercices
it has been observed that AOA level does
not change; whereas, MDA level increases after
physical activity. Similarly, no AOA change (for
the sample after competition) is observed at our
study (Table 1). It is also possible that the intensity
and/or the duration of exercise performed in
the present study was not great enough to produce
a significant increase in MDA and AOA.
The primary function of red blood cells is to
maintain aerobic metabolism by transporting
oxygen to, and carbon dioxide from, body tissues.
The iron atom of the heme molecule must be in
the ferrous (+2) oxidation in order for this to occur.
Certain chemical processes within the cell
oxidize the ferrous iron to the ferric (+3) state.
This molecule is known as methemoglobin and
is unable to bind oxygen, or carbon dioxide, and
is not dissociable. Methemoglobin formation is
not only affected by nitrite but also by other factors
such as rate of methemoglobin reductase,
abnormalities of the hemoglobin itself, or oxidant
chemicals. Auto-oxidation of oxyhemoglobin
to methemoglobin results in the production
of superoxide and the rate of formation of methemoglobin
can increase with exercise (Deaton et
al. 2003). In the present stduy, the methemoglobin
level in the blood of footboller after footboll
competition elevated similarly the increases of
MDA concentration. This result showed that an
enhanced production of free radicals caused the
methemoglobin formation in the blood of the
footboller.
Nitric oxide (NO) released by endothelial cells
is an important regulator of vascular function.
However, excess NO production may cause damage
in cells because of being a free radical with
vasodilatory properties of NO (Sainz et al. 2005).
After the marathon race, metabolic products of
NO in plasma of the marathon racer increased
up to 1.6 fold, probably due to increased inducible
NO synthase expression and NO synthesis
in peripheral leukocytes (Pawloski et al. 2001).
In the present study, there have been no significant
changes on metabolic products of NO (Tab.
1) most probably due to being lower duration
and intensity of football matches than marathon
races.
Many studies on the effects of physical activity
on lipid mobilization are found during the literature
investigation. Aguilo et al. (2003) reported
that the mobilisation of serum triglyceride observed
after exercise is related to the release of
free fatty acids from the periphery, mainly due
to considerable energy expenditure during the
cycling stage. In the present study, it has been
observed that intensive exercise does not effect
the triglyceride and total cholesterol levels for
people performing regular exercise (Tab. 1). An
increase in cholesterol levels has been observed
after acute exercise, but not after choronic exercise
(Aguilo et al. 2003) which agrees with our results,
because maximal exercise is acute exercise
(Short term and high intensity). Excess physical
exercise is one of the main causes of increased
free radical production and has an important role
in hyperglycemia and enhanced lipid mobilization
(Gambelunghe et al. 2001). Catecholamine metabolism,
which is also increased by exercise and
free faty acid, may also participate in the formation
of lipid peroxides (Özbay et al.2001). Another
aim of this study was to examine the effects of
changes in plasma glucose during football competition.
As observed in previous studies, plasma
glucose concentrations are increased as a result
of physical exercise.
In conclusion, our results showed that a high
competition sport leads to an increased lipid peroxidation,
unchanged antioxidant activity and elevated
methemoglobin level for football players.
This may indicate that the oxidant-antioxidant
balance is changed by intensive exercise even if
people make regular physical exercise. We suggest
that, consumption of natural antioxidants
before intensive exesrcises would have a positive
effect on being decreased the harmfull of effects
of oxidative stress to the cells.