Asako Zempo-Miyaki

Lifestyle modification increases serum testosterone level and decrease central blood pressure in overweight and obese men

Obesity has reached global epidemic proportions and is associated with multiple comorbidities, including cardiovascular disease. A novel predictor of cardiovascular disease is elevated central systolic blood pressure. In fact, lifestyle modifications have been shown to decrease the central systolic blood pressure in overweight and obese men. The mechanism underlying these changes has yet to be fully elucidated. Interestingly, testosterone has been found to have cardioprotective effects. Moreover, serum testosterone levels are lower in obese men than in normal weight men. However, it is still unclear whether testosterone participates in the decrease of central blood pressure in overweight and obese men following lifestyle modifications. So, the purpose of the present study was to investigate the effect of testosterone on central systolic blood pressure in overweight and obese men before and after the 12-week lifestyle modification program. Forty-four overweight and obese men completed a 12-week lifestyle modification program (aerobic exercise training and dietary modifications). For all participants, central systolic blood pressure and serum testosterone levels were measured before and after the program. After the program, central systolic blood pressure was significantly decreased while serum total testosterone levels were significantly increased in overweight and obese men. Moreover, we also found a significant negative relationship between the change in serum testosterone levels and that in central systolic blood pressure. The present study suggests that increased serum testosterone levels likely contribute to a decrease in central blood pressure in overweight and obese men.

Lifestyle Modification Decreases Arterial Stiffness in Overweight and Obese Men: Dietary Modification vs. Exercise Training

Obesity and increased arterial stiffness are independent risk factors for cardiovascular disease. Arterial stiffness is increased in obese individuals than in age-matched nonobese individuals. We demonstrated that dietary modification and exercise training are effective in reducing arterial stiffness in obese persons. However, the differences in the effect on arterial stiffness between dietary modification and exercise training are unknown. The purpose of the current study was to compare the effect of dietary modification and aerobic exercise training on arterial stiffness and endothelial function in overweight and obese persons. Forty-five overweight and obese men (48 ± 1 year) completed either a dietary modification (well-balanced nutrient, 1680 kcal/day) or an exercise-training program (walking, 40-60 min/day, 3 days/week) for 12 weeks. Before and after the intervention, all participants underwent anthropometric measurements. Arterial stiffness was measured based on carotid arterial compliance, brachial-ankle pulse wave velocity (baPWV), and endothelial function was determined by circulating level of endothelin-1 (ET-1) and nitric oxide metabolite (nitrites/nitrate as metabolite: NOx). Body mass and waist circumference significantly decreased after both intervention programs. Weight loss was greater after dietary modification than after exercise training (-10.1 ± 0.6 kg vs. -3.6 ± 0.5 kg, p < .01). Although arterial stiffness and the plasma levels of ET-1 and NOx were improved after dietary modification or exercise training, there were no differences in those improvements between the 2 types of interventions. Exercise training improves arterial function in obese men without as much weight loss as after dietary modification.

Acute Effect of High-Intensity Eccentric Exercise on Vascular Endothelial Function in Young Men.

Abstract Choi, Y, Akazawa, N, Zempo-Miyaki, A, Ra, S-G, Shiraki, H, Ajisaka, R, and Maeda, S. Acute effect of high-intensity eccentric exercise on vascular endothelial function in young men. J Strength Cond Res 30(8): 2279–2285, 2016—Increased central arterial stiffness is as an independent risk factor for cardiovascular disease. Evidence regarding the effects of high-intensity resistance exercise on vascular endothelial function and central arterial stiffness is conflicting. The purpose of this study was to examine the effects of acute high-intensity eccentric exercise on vascular endothelial function and central arterial stiffness. We evaluated the acute changes in endothelium-dependent flow-mediated dilation (FMD), low-flow–mediated constriction (L-FMC), and arterial stiffness after high-intensity eccentric exercise. Seven healthy, sedentary men (age, 24 ± 1 year) performed maximal eccentric elbow flexor exercise using their nondominant arm. Before and 45 minutes after eccentric exercise, carotid arterial compliance and brachial artery FMD and L-FMC in the nonexercised arm were measured. Carotid arterial compliance was significantly decreased, and &bgr;-stiffness index significantly increased after eccentric exercise. Brachial FMD was significantly reduced after eccentric exercise, whereas there was no significant difference in brachial L-FMC before and after eccentric exercise. A positive correlation was detected between change in arterial compliance and change in FMD (r = 0.779; p ⩽ 0.05), and a negative correlation was detected between change in &bgr;-stiffness index and change in FMD (r = −0.891; p < 0.01) with eccentric exercise. In this study, acute high-intensity eccentric exercise increased central arterial stiffness; this increase was accompanied by a decrease in endothelial function caused by reduced endothelium-dependent vasodilation but not by a change in endothelium-dependent vasoconstriction.

Increased physical activity has a greater effect than reduced energy intake on lifestyle modification-induced increases in testosterone.

Obesity has reached epidemic proportions worldwide. Obesity results in reduced serum testosterone levels, which causes many disorders in men. Lifestyle modifications (increased physical activity and calorie restriction) can increase serum testosterone levels. However, it is unknown whether increased physical activity or calorie restriction during lifestyle modifications has a greater effects on serum testosterone levels. Forty-one overweight and obese men completed a 12-week lifestyle modification program (aerobic exercise training and calorie restriction). We measured serum testosterone levels, the number of steps, and the total energy intake. We divided participants into two groups based on the median change in the number of steps (high or low physical activities) or that in calorie restriction (high or low calorie restrictions). After the program, serum testosterone levels were significantly increased. Serum testosterone levels in the high physical activity group were significantly higher than those in the low activity group. This effect was not observed between the groups based on calorie restriction levels. We found a significant positive correlation between the changes in serum testosterone levels and the number of steps. Our results suggested that an increase in physical activity greatly affected the increased serum testosterone levels in overweight and obese men during lifestyle modification.

Elevated pentraxin 3 level at the early stage of exercise training is associated with reduction of arterial stiffness in middle-aged and older adults

Regular exercise improves aging-induced deterioration of arterial stiffness, and is associated with elevated production of pentraxin 3 (PTX3) and anti-inflammatory as well as anti-atherosclerotic effects. However, the time-dependent effect of exercise training on arterial stiffness and PTX3 production remains unclear. The purpose of this study was to investigate the time course of the association between the effects of training on the circulating PTX3 level and arterial stiffness in middle-aged and older adults. Thirty-two healthy Japanese subjects (66.2±1.3 year) were randomly divided into two groups: training (exercise intervention) and sedentary controls. Subjects in the training group completed 8 weeks of aerobic exercise training (60–70% peak oxygen uptake (VO2peak) for 45 min, 3 days per week); during the training period, we evaluated plasma PTX3 concentration and carotid–femoral pulse wave velocity (cfPWV) every 2 wk. cfPWV gradually declined over the 8-week training period, and was significantly reduced after 6 and 8 week of exercise intervention (P<0.05). Plasma PTX3 level was significantly increased after 4 weeks of the intervention (P<0.05). In addition, the exercise training–induced reduction in cfPWV was negatively correlated with the percent change in plasma PTX3 level after 6 week (r=−0.54, P<0.05) and 8 weeks (r=−0.51, P<0.05) of the intervention, but not correlated at 4 weeks. Plasma PTX3 level was elevated at the early stage of the exercise training intervention, and was subsequently associated with training-induced alteration of arterial stiffness in middle-aged and older adults.

Changes in salivary flow rate following Chlorella-derived multicomponent supplementation

Decreases in saliva secretion compromise food mastication and swallowing, reduce mucosal immune function, and increase the risk for oral diseases like dental caries. Chlorella is a green alga that contains a variety of nutrients including amino acids, vitamins, and minerals. In our previous study, Chlorella-derived multicomponent supplementation did not affect salivary flow rates in healthy young individuals, but Chlorella-derived supplementation attenuated a decrease in saliva secretion that was observed during a kendo training camp. Hence, we hypothesized that Chlorella-derived supplementation increases saliva secretion in individuals with lower rates of saliva flow. Sixty-four subjects took Chlorella-derived tablets for four weeks. Before and after supplementation, saliva samples were collected by chewing cotton. In the complete study group, there was no difference in saliva production before and after supplementation (1.91 ± 0.11 ml/min before vs 2.01 ± 0.12 ml/min after). Analysis of subgroups based on saliva production before supplementation found an increase in saliva secretion in the lower saliva flow group (1.18 ± 0.06 vs 1.38 ± 0.08 ml/min), but no change in the higher saliva flow group (2.63 ± 0.11 vs 2.64 ± 0.15 ml/min). These results suggest that Chlorella-derived multicomponent supplementation increases saliva production in individuals with lower levels of saliva secretion.

Vigorous Physical Activity is Associated with Regular Aerobic Exercise-Induced Increased Serum Testosterone Levels in Overweight/Obese Men

Testosterone is a male sex hormone and low circulating testosterone levels are associated with various health disorders in men. Obesity results in reduced circulating testosterone levels in men. Previously, we demonstrated that lifestyle modifications (combination of aerobic exercise and dietary modification) increase circulating testosterone levels in overweight/obese men. However, the effect of regular aerobic exercise on serum testosterone levels remains unclear. The purpose of this study was to investigate the effect of a 12-week aerobic exercise intervention on circulating testosterone levels in normal-weight and overweight/obese men. Sixteen normal-weight men and twenty-eight overweight/obese men completed a 12-week aerobic exercise intervention. Before and after the intervention, we measured serum total testosterone, free testosterone, and bioavailable testosterone levels, and categorized the physical activity levels (light, moderate, or vigorous) in all participants. At baseline, serum total testosterone, free testosterone, and bioavailable testosterone levels were significantly lower in overweight/obese men than in normal-weight men (all p<0.01). After the 12-week aerobic exercise intervention, serum total testosterone, free testosterone, and bioavailable testosterone levels significantly increased in overweight/obese men (p<0.01). In addition, stepwise multivariable linear regression analysis revealed the increase in vigorous physical activity was independently associated with increased serum total testosterone levels (β=0.47, p=0.011). We demonstrated that a 12-week aerobic exercise intervention increased serum total testosterone, free testosterone, and bioavailable testosterone levels in overweight/obese men. We suggest that an increase in vigorous physical activity increased circulating testosterone levels in overweight/obese men.

Habitual exercise decreases systolic blood pressure during low-intensity resistance exercise in healthy middle-aged and older individuals

Since aerobic exercise (e.g., walking) and resistance exercise (e.g., lifting objects and mopping) are both parts of the activities of daily living, an exaggerated elevation in systolic blood pressure (SBP) during aerobic and resistance exercise is an early marker of cardiovascular disease. This study investigated the effects of habitual exercise on SBP during low-intensity resistance exercise using both cross-sectional and interventional approaches. First, in 57 normotensive women (61.9 ± 1.0 yr of age), daily physical activity level, as assessed by triaxial accelerometry, was correlated with SBP during resistance exercise at 20 and 40% of the 1 repetition maximum (r = -0.408 and r = -0.348, respectively). Maximal oxygen uptake was correlated with SBP during exercise at 20% (r = -0.385) and 40% (r = -0.457). Physical activity level or maximal oxygen uptake was identified as a predictor of SBP during the exercise in stepwise regression analysis, independent of SBP at rest and other factors (R2 = 0.729-0.781). Second, 66 men and women (64.6 ± 0.9 yr of age) participated in a 6-wk intervention as a part of the training (walking, 4.3 ± 0.3 days/wk, 55.6 ± 4.1 min/day, 70.7 ± 1.2% of maximal heart rate) or control group. SBP during resistance exercise in the training group decreased after the intervention (before vs. after: 20%, 143 ± 4 vs. 128 ± 4 mmHg; and 40%, 148 ± 5 vs. 134 ± 4 mmHg). In the control group, there were no significant differences in SBP before and after the intervention. SBP during resistance exercise after the intervention was lower in the training group relative to the control group. These results suggest that habitual exercise decreases SBP during low-intensity resistance exercise.

Aerobic exercise training enhances cerebrovascular pulsatility response to acute aerobic exercise in older adults

The brains low resistance ensures a robust blood flow throughout systole and diastole and is susceptible to flow pulsatility. Increased cerebral pulsatility contributes to the progression of cerebrovascular disease. Although aerobic exercise affects vascular function, little is known about the effect of exercise on the cerebral pulsatility index in older adults. The aim of this study was to investigate the effect of exercise training on the post‐exercise cerebral pulsatility response in older adults. Ten healthy older adults participated in a 12‐week exercise training intervention. Before and after the intervention, we measured the pulsatility index of the middle cerebral artery by means of transcranial Doppler method at baseline and following a cycling exercise bout performed at an intensity corresponding to the ventilatory threshold. Before exercise training, there was no significant change in the cerebral pulsatility response to an acute bout of cycling exercise. However, after the intervention, cerebral pulsatility decreased significantly following 30 min of an acute cycling exercise (P < 0.05). This study demonstrated that cerebral pulsatility index did not change following an acute bout of cycling exercise at an intensity corresponding to ventilatory threshold, but that, after 12 weeks of exercise training, cerebral pulsatility index was reduced at 30 min after a single bout of cycling exercise. These results suggest that long‐term aerobic exercise training may enhance the post‐exercise reduction in pulsatility index in older adults.

Relationships between serum free fatty acid and pulse pressure amplification in overweight/obese men: insights from exercise training and dietary modification

Pulse pressure amplification (i.e., the ratio of peripheral to central pulse pressure) is a strong predictor of cardiovascular events. Circulating free fatty acid, which is a major cause of insulin resistance, has been reported to favorably be associated with pulse pressure amplification in the arm (from the aorta to brachial artery). We hypothesized that this paradoxical relationship depended on an evaluating site of pulse pressure amplification and investigated whether serum free fatty acid level is related to pulse pressure amplification in the arm or trunk (from the aorta to femoral artery) in overweight/obese men. In a cross-sectional study, 85 men participated, and regression analyses revealed that serum free fatty acid level was significantly and independently associated with pulse pressure amplification in the arm but not the trunk. In a longitudinal study, 33 men completed a 12-week lifestyle intervention that involved both exercise training and dietary modification. The lifestyle intervention-induced change in serum free fatty acid level was significantly correlated to that in pulse pressure amplification in the arm but not the trunk. These results support our hypothesis and suggest that pulse pressure amplification should be measured in the trunk instead of the arm in overweight/obese men to simplify its interpretation.