ABSTRACT
The purpose of this study was evaluating the effect of obesity and weight reduction induced by endurance training on UCP3 mRNA expression in C57BL/6 mice. Twenty-four C57BL/6 mice consumed a high-fat diet, while 6 [NB Group] were fed a normal chow for 12 weeks. After the fattening period, 6 obese mice [OB Group] were sacrificed. Twelve mice trained 5 sessions per week for 12 weeks on a rodent treadmill with high [HI Group] [75% VO2max] and/or low intensity [LI Group] [50% VO2max] during a training period. The control group [OC Group] was kept inactive in the cages till the end of the period. Body weight was measured and recorded weekly. UCP3 mRNA expression was measured in gastrocnemius muscle using Real Time-PCR method and plasma FFA concentrations were measured using the ELISA method. In the training groups, weight reduction was significant in the 8th week [p<0.05]. Average relative UCP3 mRNA expression was significantly lower in the HI and LI groups, than in the OC group [0.5 +/- 0.25 and 1.04 +/- 0.96, respectively, vs. 2.58 +/- 0.57 arbitrary unit; p<0.05]. Plasma FFA concentrations were significantly lower in the HI and OB groups compared to the LI group [p<0.05]. When energy intake and consequently body weight increases, UCP3 increases to extend the thermogenesis and fatty acid oxidation's process. In contrast, UCP3 downregulates with exercise-induced weight loss in order to counteract this process
ABSTRACT
Caffeine is a naturally occurring substance that is widely consumed in a variety of forms. The aim of this study was to assess the effect of caffeine on blood pressure in overweight men during exercise and at rest. In double-blind randomly designed study, six men [BMI 29.55 +/- 1.22 kg/m2, age 22.50 +/- 0.83 yr, height 174 +/- 9.12cm, weight 89.31 +/- 8.85kg, body fat percent 26.38 +/- 3.62] with sedentary lifestyles, performed 30 minutes running on treadmill at similar exercise intensities [60% VO2max], 1 hour after taking caffeine [5 mg/kg body weight] or placebo. Heart rate was recorded during exercise, and blood pressure [BP] was measured before and 1 hour after taking caffeine and immediately after exercise, and data analysis was conducted using student' t-test. Results indicated that systolic and diastolic BP and mean arterial pressure significantly elevated following caffeine intake at rest, but no significant differences were observed after exercise no significant differences were observed between caffeine and placebo in heart rate during exercise. The findings indicate that caffeine at this dosage level alters cardiovascular dynamics by augmenting arterial blood pressure in moderately obese men at rest. However, it seems that taking caffeine before exercise does not cause abnormal elevations in blood pressure in moderately obese men