Kanae Myoenzono

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.

Age-Related Declines in Executive Function and Cerebral Oxygenation Hemodynamics

Cerebral hemodynamics plays an important role in cognitive performance, and as such, age-related cognitive dysfunction and cerebral hypoperfusion increase the risk of dementia. However, age-related changes in cerebral oxygenation and cognitive function remain unclear. The aim of this study was to investigate age-related declines in cerebral oxygenation and executive function cross-sectionally. Ninety-eight healthy Japanese adults (age range: 23-79 years; 40 males, 58 females) participated in the present study using local advertisements. The participants were divided into 4 age groups: young (20-39 years; M15/F7), 50s (50-59 years; M10/F12), 60s (60-69 years; M9/F31), and 70s (70-79 years; M6/F8). We measured oxygenated hemoglobin (oxy-Hb) signal change in the prefrontal cortex during the Stroop task, and calculated Stroop interference time in cross-sectional design. This test is widely used to measure the ability to properly control attention and behavior in executing tasks, and to evaluate executive functions mainly associated with the prefrontal cortex. Oxy-Hb signal changes in the left prefrontal cortex in the 60s and 70s groups were significantly lower than those in the young group (both P < 0.05). Additionally, Stroop interference time was significantly longer in the 60s and 70s groups than in the young group (both P < 0.05). Furthermore, differences in oxy-Hb signal change between the left and right prefrontal cortex were evident only in the young group. These results suggest that the age-related decrease in executive function is associated with decrease in the cerebral oxygenation hemodynamics in the left prefrontal cortex.

Lactotripeptide ingestion increases cerebral blood flow velocity in middle-aged and older adults

The age-related decrease in cerebral blood flow velocity increases the risk of cerebrovascular disease. Milk protein-derived bioactive peptides, e.g., lactotripeptide (LTP), have been shown to inhibit angiotensin converting enzyme activities and increase vasodilator production. We hypothesized that LTP ingestion increases cerebral blood flow velocity in middle-aged and older adults. In a randomized, placebo-controlled, double-blind design, 15 healthy middle-aged and older adults were assigned to either a LTP group or a placebo group. The subjects ingested LTP or placebo orally for 8 weeks. Before and after intervention, middle cerebral blood flow velocity was measured using transcranial Doppler ultrasonography. The baseline middle cerebral blood flow velocity and most other key dependent variables did not differ between the groups. LTP ingestion significantly increased middle cerebral blood flow velocity, but there was no such improvement in the placebo groups. We concluded that 8 weeks of LTP ingestion increased middle cerebral blood flow velocity in middle-aged and older adults.

Sexual Function Is an Indicator of Central Arterial Stiffness and Arterial Stiffness Gradient in Japanese Adult Men

Background As arterial stiffness increases in the absence of subjective symptoms, a personal indicator that reflects increased risk of cardiovascular disease is necessary. Penile erection is regulated by vascular function, and atherosclerosis affects the penile artery earlier than it affects the coronary and carotid arteries. Therefore, we hypothesized that deterioration of erectile function could be a marker of increased risk for cardiovascular disease. To test our hypothesis, we assessed erectile function and arterial stiffness in a cross‐sectional study. Methods and Results Carotid‐femoral pulse wave velocity (PWV), brachial‐ankle PWV, femoral‐ankle PWV, and arterial stiffness gradient (PWV ratio: carotid‐femoral PWV/femoral‐ankle PWV) were measured as indexes of central, systemic, and peripheral arterial stiffness and peripheral organ damage, respectively, in 317 adult men. In addition, erectile function was assessed by using the questionnaire International Index of Erectile Function 5 (a descending score indicates worsening of erectile function). The scores of male sexual function were inversely correlated with carotid‐femoral PWV (r s=−0.41), brachial‐ankle PWV (r s=−0.35), femoral‐ankle PWV (r s=−0.19), and PWV ratio (r s=−0.33). Furthermore, multivariate linear regression analyses revealed that International Index of Erectile Function 5 scores were significantly associated with carotid‐femoral PWV (β=−0.22) and PWV ratio (β=−0.25), but not with brachial‐ankle PWV and femoral‐ankle PWV. Conclusions Our results indicated that erectile function is independently associated with central arterial stiffness and peripheral organ damage. These findings suggest that male sexual function could be an easily identifiable and independent marker of increased central arterial stiffness and peripheral organ damage.

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.

Aerobic exercise training normalizes central blood pressure regulation after oral glucose loading in overweight/obese men

ABSTRACT Central systolic blood pressure (cSBP) decreases after a meal or glucose challenge, but this response is impaired in obesity-related disorders. We investigated whether aerobic exercise training improves cSBP regulation during an oral glucose tolerance test (OGTT) in overweight/obese men. Thirteen overweight/obese men and six normal-weight men (as an alternative comparison instead of a no-exercise group) completed a 12-week aerobic exercise training program. Before and after the program, cSBP (i.e., radial second systolic pressure) was measured using an applanation tonometry at fasting and both 60 min and 120 min after 75 g glucose loading. Before and during the program, physical activity (PA) time was recorded using a tri-axial accelerometer. Pre-training, cSBP was significantly decreased with glucose loading in normal-weight men, while cSBP did not change in overweight/obese men. Post-training, a significant decrease in cSBP was observed in both groups following glucose loading. In addition, the increase in vigorous PA time during the exercise program was significantly correlated to the increase in area above the curve for cSBP during OGTT (demonstrating an improvement in the cSBP response to glucose loading) after the exercise program. These findings may provide novel insights into the role of PA in reducing the cardiovascular risk in obesity.

Pentraxin3 increases in adult overweight and obese men after weight-loss by dietary modification with exercise training

The circulatory level of pentraxin 3 (PTX3), an anti-inflammatory cardioprotective protein, has been shown to be lower in obese individuals than in those with normal weight. However, reports on the effects of different weight-loss methods on PTX3 are limited. The present study aimed to investigate the effect of weight loss on circulating PTX3 levels in overweight and obese men and to examine the combined effect of dietary modification and exercise training on PTX3 levels. Forty-eight overweight and obese men were assigned to 2 groups: dietary modification (group D) or exercise training and dietary modification (group DE). Groups D and DE were composed of 27 and 21 participants, respectively. We observed a significant independent relationship between changes in PTX3 and body mass index (BMI) in all participants (β = -0.617, p < 0.01). Subsequently, we compared the effects of the 2 weight-loss methods on plasma PTX3 in groups D and DE. The magnitude of the increase in plasma PTX3 levels was similar in the 2 groups. Interestingly, we observed that PTX3 levels in group DE increased significantly more than those in group D in subjects who achieved normal weight, based on BMI, after interventions. Our study suggested that weight reduction after lifestyle modification significantly increased PTX3 levels in overweight and obese men, and the addition of habitual exercise to dietary modification enhanced the magnitude of the increase in PTX3 levels in obese individuals achieving normal weight after weight loss.