Abstract
Objectives Oxidative stress, induced by physical activity, may stimulate the expression, release, and activity of certain antioxidant enzymes. We investigated the effect of three repeated bouts of strenuous exercise on paraoxonase 1 concentration (PON1c) and paraoxonase activity (PON). Methods Eleven average-trained healthy men (age 34.0 ± 5.2 years) performed three strenuous exercise tests on a treadmill separated by 72 hours periods of resting. PON1c, PON, ferric-reducing activity of plasma (FRAP), lipid profile, C-reactive protein concentration (CRP), and lactate concentration were determined in plasma. Results Each exercise bout resulted in similar PON1c, PON, FRAP, and high-density lipoprotein concentration (HDL-C) increments, while PON/HDL-C ratio remained stable in all repetitions. Percentage increments at the bout of each exercise were higher for PON1c (by 64.82% at the first, by 92.9% at the second, and by 77.02% at the third exercise) than for PON (by 6.49% at the first, 10.06% at the second, and by 12.32% at the third exercise). Association was found between preexercise PON and PON1c (r = 0.56, p = 0.029), pre- (r = 0.87, p = 0.00003) and postexercise HDL-C (r = 0.6, p = 0.0002), preexercise PON and cardiovascular fitness level of participants measured as VO2max (r = 0.39, p = 0.026), and postexercise PON and lactate concentration (r = 0.44, p = 0.01). Conclusions PON1c and PON increase during strenuous exercise, yet the effect of exercise on PON1 concentration is more pronounced. PON1 does not show tolerance to physical activity. The enzyme may provide short-term protection from oxidative stress in each exercise bout. PON may depend on exercise load. Cardiovascular fitness levels may be associated with PON1 activity.
Highlights
There is substantial evidence proving that a single strenuous exercise induces oxidative stress
Already in the 2nd run and in the 3rd run, we observed an adjustment to this form of exercise and equipment, which resulted in the potential to complete a prolonged treadmill run
We have found an association between PON1 arylesterase activity after maximal exercise and the combination of maximal HR and VO2max/HR, proving some but not strong association between physical fitness and PON1 activity [10]
Summary
There is substantial evidence proving that a single strenuous exercise induces oxidative stress. As oxygen consumption increases up to 20-fold during endurance exercise, the production of reactive oxygen species (ROS) exceeds the body’s ability to detoxify them. ROS produce adverse modifications to cell components, such as lipids, proteins, and DNA [1, 2]. It seems reasonable that in the case of regularly repeated endurance exercise, defensive mechanisms. Oxidative Medicine and Cellular Longevity must be developed in human plasma, which fight the deleterious effects of oxidative stress. Those mechanisms involve various antioxidants, among which PON1 may play an important role
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