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We studied the effects of different types of exercises on the concentrations of oxidised HDL (oxHDLlipids) and LDL lipids (oxLDLlipids), serum lipids, antioxidant potential, paraoxonase and malondialdehyde in endurance runners by performing both a 40-min continuous run (velocity corresponding to 80% VO2max) and a 40-min intermittent run (2-min run, velocity corresponding to 100% VO2max, and 2-min rest) using a treadmill. Blood samples were taken before exercise, after 20 and 40 min of exercise, and 15 and 90 min after the end of exercise. The concentrations of oxLDLlipids remained unchanged during the running tests, but after a 90-min recovery the concentrations decreased by 4% (P

We studied effects of probiotics and training volume on oxidized LDL lipids (ox-LDL), serum antioxidant potential (s-TRAP) and serum antioxidants (s-α-tocopherol, s-γ-tocopherol, s-retinol, s-β-carotene and s-ubiquinone-10) in marathon runners during 3-months training period, 6-days preparation period and marathon run. Runners (n=127) were recruited for a randomized, double-blind intervention during which they received either Lactobacillus rhamnosus GG (LGG, probiotic group) or placebo drink (placebo group) during whole study. During the preparation period, subjects decreased training and increased carbohydrate intake. Blood samples were taken at baseline, before 6-days preparation, before and immediately after the marathon. Probiotics did not have any effect on ox-LDL, s-TRAP or serum antioxidants levels during the study. Interestingly, ox-LDL increased by 28% and 33% during the preparation period and decreased by 16% and 19% during the marathon run in the placebo and probiotic groups, respectively (in all, P0.001). No changes were seen in s-TRAP before marathon, but during run s-TRAP raised by 16% in both groups (both, P0.001). The increase of ox-LDL level during the preparative period after several months' training suggests that aerobic training may reduce the concentration of ox-LDL and that decrease of training together with increased energy intake, mainly carbohydrate, before marathon is capable of increasing the level of ox-LDL.

In order to study the effects of different athletic backgrounds on exercise-induced hormonal responses, serum testosterone, luteinizing hormone, follicle-stimulating hormone and cortisol concentrations were measured before and after intensive continuous and intermittent running in well-trained middle-distance runners (MID) and marathon runners (MAR). They performed two 40-min exercises on a treadmill: a continuous run at an intensity of 80% [tempo run (TR)] and an intermittent run (IR) at an intensity of 100% of the velocity associated with VO(2max). The testosterone response to IR and the cortisol response to TR was higher (P

Physical exercise has cardioprotective functions, which have been partly linked to high-density lipoprotein (HDL), and its functions. We studied the effects of endogenous oxidative stress, induced by acute exhaustive physical exercise, on concentration of oxidized HDL lipids.Twenty-four male national top-level endurance runners, 12 middle-distance runners and 12 marathon runners performed a maximal run on a treadmill until exhaustion. We analyzed concentrations of oxidized HDL (oxHDLlipids) and LDL lipids (oxLDLlipids), serum antioxidant potential (TRAP), paraoxonase activity and malondialdehyde. Venous blood samples were taken before, immediately, 15 and 90 min after exercise.Immediately after the treadmill run the concentration of oxHDLlipids was increased by 24 % (p 0.01). Simultaneously, the ratio of oxHDLlipids to oxLDLlipids increased by 55 % and the oxLDLlipids levels decreased by 19 % (p 0.001), while serum malondialdehyde and TRAP increased by 54 % (p 0.001) and 29 % (p 0.01), respectively. After the 90 min recovery the concentration of oxHDLlipids was decreased towards the pre-exercise level, but that of oxLDLlipids remained decreased below pre-exercise values (p 0.001). The change in oxLDLlipids after the run correlated positively with VO2max (r = 0.67, p 0.001) and negatively with the change in paraoxonase activity (r = -0.47, p 0.05).We conclude that acute exhaustive physical exercise increased the concentration of oxHDLlipids and decreased that of oxLDLlipids and the ratio of oxLDLlipids to oxHDLlipids, which suggests that during physical exercise HDL has an active role in the removal of lipid peroxides.

This study investigated acute changes in muscle activation and muscular power performance after three different running exercises in elite long-distance runners. Twenty-two nationally and internationally ranked long-distance runners performed first an incremental treadmill running test until exhaustion (MR) and then 40 min continuous (TR) and intermittent (2 min run/2 min rest) (IR) running exercises at an intensity of 80 and 100% of the velocity associated with VO(2max), respectively. Muscle activation and muscular power performance tests (counter-movement jumps, CMJ, and a set of ten maximal half squats from the static starting position with an extra load of 35% of the subjects, one repetition maximum) were performed before and immediately after the runs. The average mechanical power (P) of the half squats was calculated and the root mean square electromyogram (EMGrms) from the vastus lateralis, vastus medialis, gastrocnemius and biceps femoris muscles was recorded simultaneously during the half squat performances. The results showed an acute exercise-induced increase in P (ANOVA time effect, P = 0.000) together with a reduction in EMGrms of the knee extensor muscles (ANOVA time effect, P = 0.000). However, mechanical P expressed as a relative change within the set decreased after MR. In TR the improvement in P correlated positively with the maximal running performance of the runners (P0.05), while in IR it correlated negatively (P0.05). Jumping performance was significantly enhanced after each run (P0.001, for all) and the improvement correlated negatively with the maximal sprinting speed and maximal jumping height of the runners (P0.01, for all). It is concluded that in elite long distance runners an intensive prolonged running exercise reduces the surface EMG of the knee extensor muscles, and may lead to a different coordination strategy in leg extension exercises performed into the vertical direction. After continuous type of running the power improvement correlates positively with maximal endurance running capacity, whereas after intermittent type of running it correlates negatively.

We investigated the acute effects of long-distance running on oxidation of lipids and antioxidant functions in LDL and serum. Eight trained male runners who participated in a 31-km run and 22 male keep-fit runners who participated in a marathon run were enrolled into the study. Venous blood samples were taken before and immediately after the exercise. There were no changes in LDL diene conjugation (LDL-DC) or LDL antioxidant potential (LDL-TRAP) during the exercises. Serum (S-) TRAP and S- α -tocopherol rose during the 31-km run (by 22%, p = .0005, and by 29%, p = .011, respectively), and during the marathon (by 16%, p = .0014, and by 7%, p = .031, respectively). S-DC rose during the 31-km run (by 9%, p = .0026), but not during the marathon ( p = .14). Preexercise and postexercise S- α -tocopherol correlated positively with pre and postexercise S-TRAP in the marathon run ( r = .473, 95% CI 0.064 to 0.746, and r = .524, 95% CI 0.131 to 0.774, respectively). Thus, the paradoxical exercise-associated increase in S-TRAP is, at least in part, explained by a simultaneous rise in S- α -tocopherol concentration. However, acute exercise does not change LDL-DC or LDL-TRAP concentrations. Copyright © 1996 Elsevier Science Inc.

Serum lipoproteins, the carriers of cholesterol and other lipophilic substances in blood, are known to contain variable amounts of lipid peroxides. We investigated the transport of food-derived and endogenously formed lipid peroxides by serum lipoproteins under physiological conditions.Five independent trials were conducted in which different groups of healthy volunteers either consumed a test meal (a standard hamburger meal rich in lipid peroxides) or underwent strenuous physical exercise. The transport function was characterized by analyzing the kinetics of lipid peroxides in lipoprotein fractions. For evaluation of their potential involvement, indicators of oxidative stress (8-isoprostanes, malondialdehyde, 8-oxo-deoxyguanosine), antioxidant functions (total antioxidant potential, paraoxonase activity), and serum lipids were also analyzed.We found that food lipid peroxides are incorporated into serum triglyceride-rich lipoproteins and low-density lipoprotein, directing the flow of lipid peroxides towards peripheral tissues. High-density lipoprotein appears to have an opposite and protective function, and is able to respond to oxidative stress by substantially increasing the reverse transport of lipid peroxides.We propose that the specific atherosclerosis-related effects of serum lipoproteins are not explained by cholesterol transport alone and may rather result from the transport of the more directly atherogenic lipid peroxides.

Heavy exercise is associated with an increased risk of upper respiratory tract infections. Strenuous exercise also causes gastrointestinal (GI) symptoms. In previous studies probiotics have reduced respiratory tract infections and GI symptoms in general populations including children, adults, and the elderly. These questions have not been studied in athletes before. The purpose of this study was to investigate the effect of probiotics on the number of healthy days, respiratory infections, and GI-symptom episodes in marathon runners in the summer. Marathon runners (N = 141) were recruited for a randomized, double-blind intervention study during which they received Lactobacillus rhamnosus GG (LGG) or placebo for a 3-mo training period. At the end of the training period the subjects took part in a marathon race, after which they were followed up for 2 wk. The mean number of healthy days was 79.0 in the LGG group and 73.4 in the placebo group (P = 0.82). There were no differences in the number of respiratory infections or GI-symptom episodes. The duration of GI-symptom episodes in the LGG group was 2.9 vs. 4.3 d in the placebo group during the training period (P = 0.35) and 1.0 vs. 2.3 d, respectively, during the 2 wk after the marathon (P = 0.046). LGG had no effect on the incidence of respiratory infections or GI-symptom episodes in marathon runners, but it seemed to shorten the duration of GI-symptom episodes.

We studied the effects of a 2-day walk exercise (6 h+6 h) on the serum concentration of circulating moderately oxidized LDL (LDL baseline conjugated dienes), lipids (total cholesterol, LDL cholesterol, HDL cholesterol, and triglyceride), antioxidants (alpha-tocopherol, gamma-tocopherol, beta-carotene, and ubiquinol-10), and antioxidant potential in serum (S-TRAP) and LDL (LDL-TRAP) in healthy well-trained men. The exercise was performed twice with an interval of 14 days. While 6 h walking the subjects drank 6 cl . kg (-1) water which contained either carbohydrate (CHO trial) or placebo (PLA trial). During the 2-day exercise the level of oxidized LDL decreased by 25 % (p=0.001) in the PLA trial. At the same time serum gamma-tocopherol decreased by 20 % (p=0.049), while the other measured antioxidants remained unchanged and the serum antioxidant potential increased by 22 % (p=0.018). Serum total cholesterol decreased by 3 % (p=0.017), serum triglycerides by 22 % (p=0.001), and LDL-cholesterol by 14 % (p=0.045). HDL cholesterol increased by 9 % (p=0.001). The results in the carbohydrate trial were similar to the ones in the PLA trial. The findings suggest that exercise of long duration but of low, non-exhaustive intensity decreases the concentration of circulating oxidized LDL simultaneously with an increase in serum antioxidant potential in healthy trained men. Carbohydrate ingestion during the exercise does not have any further effect on these changes.

The responses of serum myocellular proteins and hormones to exercise were studied in ten well-trained middle-distance runners [maximal oxygen consumption (VO(2max)) = 69.4 (5.1) ml x kg(-1) x min(-1)] during 3 recovery days and compared to various measures of physical performance. The purpose was to establish the duration of recovery from typical intermittent middle-distance running exercises. The subjects performed, in random, order two 28-min treadmill running exercises at a velocity associated with VO(2max): 14 bouts of 60-s runs with 60 s of rest between each run (IR(60)) and 7 bouts of 120-s runs with 120 s of rest between each run (IR(120)). Before the exercises (pre- exercise), 2 h after, and 1, 2 and 3 days after the exercises, the same series of measurements were performed, including those for serum levels of the myocellular proteins creatine kinase, myoglobin and carbonic anhydrase III (S-CK, S-Mb and S-CA III, respectively), serum hormones testosterone, Luteinizing hormone, follicle-stimulating hormone and cortisol (S-testosterone, S-LH, S-FSH and S-cortisol, respectively) and various performance parameters: maximal vertical jump height (CMJ) and stride length, heart rate and ratings of perceived exertion during an 8-min run at 15 km x h(-1) (SL(15 km x h(-1)), HR(15 km x h(-1)) and RPE(15 km x h(-1)), respectively). Two hours after the end of both exercise bouts the concentration of each measured serum protein had increased significantly (P < 0.001) compared to the pre-exercise level, but there were no changes in SL(15 km x h(-1)) or CMJ. During the recovery days only S-CK was significantly raised (P < 0.01), concomitant with a decrease in CMJ (P < 0.01) and an increase in RPE(15 km x h(-1)) (P < 0.01). Hormone levels remained unchanged compared to the pre-exercise levels during the recovery days and there were no significant differences between the two exercise bouts in any of the observed post-exercise day-to-day responses. With the exception of S-CK, after IR(120) the post-exercise responses returned to their pre-exercise levels within the 3 days of recovery. The present findings suggest that a single 28-min intermittent middle-distance running exercise does not induce changes in serum hormones of well-trained runners during recovery over 3 days, while changes in S-CK, CMJ and RPE(15 km x h(-1)) indicate that 2-3 days of light training may be needed before the recovery at muscle level is complete.

Three modifications of the maximal anaerobic running test (MART) were compared in sprinters (Spr, n = 5), middle-distance runners (Mid, n = 5) and marathon runners (Mar, n = 6). The MART1, MART3 and MART5 consisted of n sets of 1.20-s, 3.20-s and 5.20-s runs, respectively, on a treadmill with 40-s recovery between the runs and 100-s recovery between the sets. In each MART the velocity of the first set of runs was 3.0 m.s-1 and the slope 4 degrees. Thereafter, the velocity was gradually increased by 0.38 m.s-1 for each consecutive set until exhaustion. After each set and after exhaustion fingertip blood samples were taken to determine lactate concentration and three counter-movement jumps (CMJ) were performed. Maximal (Pmax) and submaximal (P4mM) running power in each MART was expressed as the oxygen demand (ml.kg-1.min-1) of the runs. In MART1, Mar had a significantly lower Pmax than Mid or Spr (mean +/- SD; 97.8 +/- 5.4 vs. 121.0 +/- 4.4 vs. 119.2 +/- 5.4 ml.kg-1.min-1), while in MART3 the groups did not differ significantly, and the sprinters were unable to perform MART5. Mar, Mid and Spr attained the lower Pmax the more runs per set in MART (p < 0.01). Mar had the higher peak blood lactate the more runs each set consisted of (p < 0.001). In Mid and Spr, the peak blood lactate did not differ significantly between the MARTs but was significantly higher than the corresponding peak blood lactate of the marathon runners. Pmax in MART1 correlated positively with maximal 20-m sprinting speed on a track and with CMJ height (p < 0.001, n = 16) but negatively with VO2 max (p < 0.001, n = 16) while in MART3 no significant correlations were found. It was concluded that the n.1.20-s protocol should be used to measure the maximal anaerobic power of all runners. However, in long-distance runners more runs per set may be needed to evaluate their anaerobic capacity.

By means of a 5-week vitamin B-complex .supplementation, associations between indices of vitamin B1, B2, and B6, status (activation coefficients [AC] for erythrocyte transketolase, glutathione reductase, and aspartate aminotransferase) and exercise-induced blood lactate concentration were studied. Subjects, 42 physically active college students (18–32 yrs), were randomized into vitamin (n=22) and placebo (n=20) groups. Before the supplementation there were no differences in ACs or basal enzyme activities between the groups. The ACs were relatively high, suggesting marginal vitamin status. In the vitamin group, all three ACs were lower (p

Variations in heart rate during exercise correlate with changes of exercise intensity and may be measured directly by radiotelemetry and continuous ECG recording. The heart rate can also be recorded in the memory of a microcomputer, which can be carried on the wrist as easily as a watch. The device has a transmitter and a receiver. By recording the heart rate during a training session or a segment of training, and calculating the average of the heart rate and comparing this average to both the maximum heart rate of the individual and his heart rate at rest, the relative heart rate to the intensity of the work load (% maximum heart rate) can be calculated. These results are useful in planning optimal training intensities for both the healthy and rehabilitating athlete. The use of target heart rate as a tool for exercise prescription is common. It represents the percentage difference between resting and maximum heart rate added to the resting heart rate. For calculating target heart rate there are also 2 other methods. The first represents the percentage of the maximum heart rate (%HRmax) calculated from zero to peak heart rate. The second represents the heart rate at a specified percentage of maximum MET (V2max). An appropriate individual heart rate for each level of an endurance performance is best determined in the laboratory. This is carried out by increasing the speed of the runner in stages on a treadmill and by measuring the oxygen uptake, the lactic acid concentration in the blood and corresponding variations in the heart rate. From these results the running speed and heart rate corresponding to aerobic, partly anaerobic or strongly anaerobic running can be determined. The %HRmax values obtained by continuous ECG recording and telemetry have been used to measure the physical work load in alpine skiing. Alpine skiing has been recorded as exercise which improves general physical fitness and aerobic capacity. However, it has been found to increase more the anaerobic capacity than the aerobic capacity. This should be taken into consideration when planning the training of general physical fitness of alpine skiers.