Maximal strength training improves endothelial function similar to that observed after moderate intensity endurance training in obese adults

BACKGROUND: The worldwide epidemic of obesity requires cost-effective tools such as strength- and endurance training for prevention and rehabilitation. Maximal oxygen uptake and endothelial function are now established as robust markers of future cardiovascular morbidity and mortality. It is well established that obesity and endurance training reduce and improves both, respectively, whilst little is known about the effects of maximal strength training. The present study determines the effects of moderate- and high-intensity (interval-training) exercise and maximal strength training upon maximal oxygen uptake and endothelial function in obese adults. METHODS: 62 adults with BMI of 36 ± 5 were randomized to either 12 weeks, 3-times per week of high-intensity interval training (HIT) (92.5% of maximal heart rate), moderate intensity (MIT) (70% of maximal heart rate; covered the same distance as individuals in the HIT-group so that only exercise-intensity differed) or a maximal strength training group (ST) (4RM × 5 in leg-press and 3 × 20 repetitions of exercise for abdominal and back muscles). Endothelial function in the brachial artery was measured by ultrasound. Results Body weight and BMI decreased significantly (p < 0.05) in both endurance training-groups and tended to decrease in strength trained subjects (p=0.11). Maximal oxygen uptake increased by 34% in HIT (p < 0.001), 16% in MIT (p < 0.001), and 10 % in ST (p < 0.01). Endothelial dysfunction was reversed in all training groups, but the effect on flow mediated dilatation was most pronounced in the HIT group. No traditional blood-marker of cardiovascular disease changed during the experimental period. CONCLUSION: Maximal strength training improves endothelial function similar to that observed after moderate intensity endurance training in obese adults. Whether the effects are additive to that observed in endurance-trained subjects should be addressed in future studies.