Wanda Pilch, Zbigniew Szygula, Anna K. Tyka, Tomasz Palka, Aleksander Tyka, Tomasz Cison, Pawel Pilch, Aneta Teleglow
Department of Physiology and Biochemistry, University School of Physical Education, Cracow, Poland, Department of Sports Medicine, University School of Physical Education, Cracow, Poland, Department of Recreation and Biological Regeneration, University School of Physical Education, Cracow, Poland, Rydygier Memorial Hospital, Cracow, Poland, Department of Clinical Rehabilitation, University School of Physical Education, Cracow, Poland, Institute of Physical Education, State Higher Vocational School, NowySa ̨cz, Poland
The aim of the study was to investigate pro-oxidant-antioxidant balance in two series of examinations with two types of stressors (exogenous heat and the combined exogenous and endogenous heat) in trained and untrained men. The exogenous stressor was provided by Finnish sauna session, whereas the combined stressor was represented by the exercise in elevated ambient temperature. The men from the two groups performed the physical exercise on a cycle ergometer with the load of 5362% maximal oxygen uptake at the temperature of 3361C and relative humidity of 70% until their rectal temperature rose by 1.2C. After a month from completion of the exercise test the subjects participated in a sauna bathing session with the temperature of 9662uC, and relative humidity of 1665%. 15-minutes heating and 2-minute cool-down in a shower with the temperature of 20uC was repeated until rectal temperature rose by 1.2C compared to the initial value. During both series of tests rectal temperature was measured at 5-minute intervals. Before both series of tests and after them body mass was measured and blood samples were taken for biochemical tests. Serum total protein, serum concentration of lipid per-oxidation products and serum antioxidants were determined. The athletes were characterized by higher level of antioxidant status and lower concentration of lipid per-oxidation products. Physical exercise at elevated ambient temperature caused lower changes in oxidative stress indices compared to sauna bathing. Sauna induced a shift in pro-oxidant-antioxidant balance towards oxidation, which was observed less intensively in the athletes compared to the untrained men. This leads to the conclusion that physical exercise increases tolerance to elevated ambient temperature and oxidative stress.
Pro-oxidant-antioxidant balance (PAB) is a state of dynamic balance established under conditions of homoeostasis between free radicals that are created and those consumed (scavenged). This definition concerns cells, body fluids or other human body components. This equilibrium is subjected to permanent dynamic changes caused either by physiological (physical exercise) or pathological factors (illness, presence of xenobiotics or UV radiation). Physical exercise of great intensity involves muscle damage, which is caused by free radicals that contribute to a more intensive lipid per-oxidation. Studies have demonstrated that exercise-induced oxidative damage depends on exercise intensity and duration. One of the elements of body adaptation to regular exercise is elevated concentration of antioxidants, also observed after training sessions. Increased oxidative stress is induced by an increased production of free radicals, reduced number of scavengers and decreased activity of enzymatic systems responsible for their removal, which often coexist with each other. In the active muscle oxidative stress is generated when aerobic metabolism is increased due to the production of reactive oxygen and nitrogen species (RONS). An important factor which promotes oxidative processes is an increased core body temperature. Physical exercise performed in the environment leads to considerable dehydratioN and oxidative stress. Both factors negatively impact the exercise efficiency. Furthermore passive body overheating also shifts the pro-oxidant-antioxidant balance towards oxidation. For this reason the authors emphasized thermal factor when defining research problems. However at this time it is not clear how both factors: passive overheating induced by sauna bathing and physical exercise in elevated ambient temperature modify pro-oxidant-antioxidant balance in human body. Therefore we conducted this study to investigate modifications in pro-oxidant-antioxidant balance due to only exogenous heat and the combination of exogenous and endogenous heat in athletes and untrained men.