Effects of aerobic continuous and interval training on rate-pressure product in patients after CABG surgery.

AIM: Rate- pressure product (RPP) is an indirect index of myocardial oxygen consumption of patients with coronary artery disease. Effects of aerobic continuous and interval exercise training on RPP in patients after coronary artery bypass graft (CABG) surgery was examined in this study. METHODS: Thirty male patients after CABG surgery were divided into aerobic continuous (AC) training (N.=11), aerobic interval (AI) training (N.=11) and control (C) (N.=8) group. AC training included 30-60 minutes at 70-85% of peak heart rate and AI training lasted 28 to 45 minutes (3 intervals for 9-15 min) at 75-90% of peak heart rate. Exercise training program was performed 3 day/week for 8 weeks. Paired t-test was used for analyzing data. RESULTS: A significant decrease in resting and maximal RPP and RPP at 3th, 6th and 9th minutes of exercise was found in AC and AI training vs. control group (P<0.05). No significant difference was found in RPP at 1th, 2th and 3th minutes of recovery in 2 training groups (P>0.05). CONCLUSION: Both high intensity AC and AI training program are effective on RPP in patients after CABG surgery and enhance efficiency of myocardium and its metabolic demands, but AI training program is more effective.

The effect of aerobic continuous and interval training on left ventricular structure and function in male non-athletes.

Exercise plays an important role to improve cardiovascular performance. The aim of this study was to compare the effect of aerobic continuous and interval training on the left ventricular structure and function. Twenty untrained healthy male students (aged 18-22 years) were randomly divided into two groups: continuous (C; n = 10) and interval (I; n = 10). The training programme consisted of countryside jogging for 45 min during 8 weeks three times a week at 70% of maximum heart rate (MHR). In each session group C was jogging for 45 min and in group I jogging was performed in 5 nine-minute stages with a four-minute inactive rest between them. M-mode, 2-dimensional, colour and Doppler transthoracic echocardiography were performed, during resting conditions, before and after the training period. After 8-week training the end diastolic diameter, systolic blood pressure and diastolic blood pressure in groups C and I, and the posterior wall thickness and the end systolic diameter in group I showed no significant difference (P > 0.05). On the other hand, the percentage of ejection fraction and shortening fraction in groups C and I, the end systolic diameter and the posterior wall thickness in group C and the interventricular septum thickness in group I demonstrated a significant difference (P ≤ 0.05). Comparing the two groups, only the value of the interventricular septum thickness was significant (P ≤ 0.05). In general, eight-week aerobic continuous and interval training can affect left ventricular structure and function.

Effect of various ratios of carbohydrate-protein supplementation on resistance exercise-induced muscle damage.

AIM: Previous studies have indicated that exercise-induced muscle damage might be attenuated by coingestion of protein and carbohydrate supplement. The purpose of this study was to compare the effect of three various ratios of carbohydrate-protein (CHO+PRO) supplements on resistance exercise-induced muscle damage indices. METHODS: Twenty-eight untrained male students voluntarily participated in this study and were randomly assigned to one of the four groups: 1) CHO+PRO 2:1 ratio, N.=7; 2) CHO+PRO 3:1 ratio, N.=8; 3) CHO+PRO 4:1 ratio, N.=7; 4) placebo group, N.=6. They performed a single bout of resistance exercise (whole body: 3 set×8-10 reps with 70-75% 1RM), with eccentric concentration. Every group consumed prepared CHO/PRO beverages (9% concentration, 10 mL/kg/bw-1 at different ratios) or the same amount of placebo beverage before and in 15 min intervals during exercise. Blood samples were taken before the exercise bout and also at 1 and 24 h post-exercise. In addition, muscle soreness scores were recorded before and 1, 24, and 48 h postexercise. Repeated measures ANOVA (between-within design) and Bonferroni post hoc test were used to analyze dependent measures (α=0.05). RESULTS: Serum creatine kinase (CK) and myoglobin (Mb) increased in all groups compared with pre-exercise but the significant difference among groups was observed in 24 h postexercise, in a way that both CK and Mb levels were higher in placebo group. Muscle soreness increased for all groups from pre to postexercise, but there was not any significant difference among groups at any time point. CONCLUSION: Findings of this study showed that CHO+PRO decreased serum CK and Mb at 24 h post exercise, but did not affect muscle soreness at any time points after exercise. Moreover, there were no significant differences between various ratios of CHO-PRO supplementation.

Oxidative stress responses in physical education students during 8 weeks aerobic training.

AIM: This study aimed to evaluate responses of selected markers of oxidative stress in physical education students during aerobic training. METHODS: Twenty male students were randomly assigned into either a control (mean+/-SD: age 23.5+/-1.4 years, height 1.72+/-0.06 m, body mass 68.9+/-5.8 kg, n=10) or an aerobic training (mean+/-SD: age 23.8+/-1.8 years, height 1.66+/-0.03 m, body mass 65.5+/-4.8 kg, n=10, 3 training sessions per week, 8 weeks, running at 75-80% of HR(max)) group. Plasma samples, collected at rest and after exercise to exhaustion before and after 8 weeks, were analysed for the determination of selected markers of oxidative stress (malondialdehyde MDA, carbonylated proteins CP, and creatine kinase CK). RESULTS: Aerobic training caused a 10% increase in maximal oxygen consumption (VO(2max)) and a 9% increase in exercise time to exhaustion (P<0.05). The aerobic training did not significantly change (P>0.05) MDA and CP levels at rest and after exercise to exhaustion. An exhaustive exercise caused a substantial increase (P<0.05) of CK in both groups independent of treatment and time of measurement. However, aerobic training did not prevent serum CK from increasing after exercise to exhaustion (P>0.05). CONCLUSIONS: It can be concluded that this pattern of moderate aerobic exercise training did not have any effect on oxidative stress levels in moderately trained physical education students, whereas it enhanced their functional performance and aerobic power of these physical education students.

Effects of vitamin E supplementation on oxidative stress at rest and after exercise to exhaustion in athletic students.

AIM: The purpose of this study is to determine the effect following exercise to exhaustion of vitamin E supplementation on oxidative stress in athletic students. METHODS: Twenty male students voluntarily participated in the study and were randomly assigned (double blind) to either a vitamin E (daily dose of 450 mg of a-tocopherol for a period of 8 weeks) or a placebo group (took capsules containing 450 mg of lactose for 8 weeks). Before and after 8 weeks blood samples were collected at rest and after exercise to exhaustion. Oxidative stress markers were malondialdehyde (MDA), carbonylated proteins (CP) and creatine kinase (CK). Also, the effect of vitamin E on ergometer cycling time, as an example of endurance performance, was evaluated. RESULTS: ANOVA and independent t-tests indicated that vitamin E supplementation did not significantly change (P > 0.05) MDA, CP and CK values at rest, after exercise to exhaustion, and cycling time, but plasma volume after exercise to exhaustion significantly decreased (P < 0.05). CONCLUSIONS: Although vitamin E supplementation had no effect on exercise performance or capacity in athletic students, further investigation is required using larger numbers of subjects and measures of vitamin E before unequivocal conclusion can be stated.