Resistance exercise training attenuates alcohol-induced cardiac oxidative stress.

BACKGROUND: Myocardial oxidative stress is believed to play an important role in the pathogenesis of alcoholic cardiomyopathy. Strenuous physical exercise has been shown to increase or decrease myocardial oxidative stress depending on the mode and duration of the exercise intervention. Given the possibility of individuals to engage in both alcohol consumption and weight-training exercise, we have examined the effect of resistance exercise training and chronic alcohol consumption on myocardial oxidative stress in rats. METHODS: Forty Sprague-Dawley rats were randomly assigned to one of four experimental groups: sedentary, sedentary plus alcohol treatment, resistance training, or resistance training plus alcohol treatment. Rats in the alcohol groups received a liquid diet containing alcohol (35% of kilocalorie intake) for 6 weeks. Non-alcohol groups were pair-fed the same liquid diet supplemented with a maltose dextrin caloric substitute. Rats in the resistance training groups were trained to rise onto their hind limbs while wearing lead-weighted vests 30 times per training session, 3 days per week during the 6 week experimental period. RESULTS: Alcohol treatment in the sedentary animals resulted in greater levels of cardiac malondialdehyde, a marker of lipid peroxidation, and a depressed index of myocardial antioxidant potential compared with all other groups (P<0.05). Hearts from the resistance training plus alcohol animals exhibited malondialdehyde and antioxidant levels similar to sedentary controls, suggesting that resistance training protected against the alcohol-induced myocardial stress. CONCLUSION: These results suggest that resistance training may attenuate the damaging effects of alcohol on the heart and preserve myocardial antioxidant capacity.

The effects of chronic alcohol consumption and exercise on the skeleton of adult male rats.

BACKGROUND: Lifestyle factors are known to affect skeletal development and integrity. Specifically, running has been reported to increase risk of fatigue fractures, whereas chronic alcohol consumption has been shown to reduce bone formation and bone mass. The combined effect of exercise and alcohol on the skeleton has yet to be explored, although alcohol consumption is common among certain physically active populations (e.g., military recruits, college athletes). It was hypothesized that chronic alcohol consumption would accentuate the inherent risk associated with endurance running exercise. METHODS: Six-month-old male Sprague Dawley rats were assigned to one of five groups: baseline, exercise-alcohol diet, exercise-normal diet, sham-alcohol diet, and sham-normal diet. Alcohol-fed rats (35% caloric intake) received a liquid diet ad libitum. Normal animals were pair-fed the identical diet with a maltose dextrin caloric substitute. Exercise was conducted on a motorized treadmill 5 days/wk for 16 weeks. Sham rats were placed on a stationary treadmill for matching time periods. Fluorochrome labels were administered 3 days before baseline and at 10 and 2 days before animals were killed. Heart, soleus, and rectus femoris muscles were wet weighed to assess the effects of training. Tibiae were collected for static and dynamic histomorphometric measurements on cancellous and cortical bone. RESULTS: Muscle weights were larger in the exercised rats versus the sham rats. Alcohol had no significant effect on skeletal muscle weight but did result in larger heart weights in both alcohol-treated groups. Cancellous and periosteal bone formation rates were significantly decreased in the alcohol-fed rats versus rats on the normal diet and were associated with a significant reduction in trabecular thickness in the tibial metaphysis. Cortical and cross-sectional areas were also significantly lower in the alcohol-fed groups compared with the non-alcohol-fed groups. Exercise had no significant effect on cancellous or cortical bone measurements. CONCLUSIONS: Chronic alcohol consumption significantly reduced bone formation. Exercise had no effect on the bone and did not attenuate any of the negative effects of alcohol. The results suggest that alcohol consumption weakens the skeleton and increases the incidence of endurance-exercise-related bone injuries. Thus, individuals who are participating in endurance exercise and consuming alcohol may be at greater risk for exercise-related skeletal injuries. Further investigation of the potential for alcohol to induce detrimental effects on the hearts of individuals participating in endurance exercise is indicated.