GH and IGF-1 in skin interstitial fluid and blood are associated with heat loss responses in exercising young adults.

PURPOSE: Sweat glands and cutaneous vessels possess growth hormone (GH) and insulin-like growth factor 1 (IGF-1) receptors. Here, we assessed if exercise increases GH and IGF-1 in skin interstitial fluid, and whether baseline and exercise-induced increases in GH and IGF-1 concentrations in skin interstitial fluid/blood are associated with heat loss responses of sweating and cutaneous vasodilation. METHODS: Sixteen young adults (7 women) performed a 50-min moderate-intensity exercise bout (50% VO2peak) during which skin dialysate and blood samples were collected. In a sub-study (n = 7, 4 women), we administered varying concentrations of GH (0.025-4000 ng/mL) and IGF-1 (0.000256-100 µg/mL) into skin interstitial fluid via intradermal microdialysis. Sweat rate (ventilated capsule) and cutaneous vascular conductance (CVC) were measured continuously for both studies. RESULTS: Exercise increased sweating and CVC (both P < 0.001), paralleled by increases of serum GH and skin dialysate GH and IGF-1 (all P ≤ 0.041) without changes in serum IGF-1. Sweating was positively correlated with baseline dialysate and serum GH levels, as well as exercise-induced increases in serum GH and IGF-1 (all P ≤ 0.044). Increases in CVC were not correlated with any GH and IGF-1 variables. Exogenous administration of GH and IGF-1 did not modulate resting sweat rate and CVC. CONCLUSION: (1) Exercise increases GH and IGF-1 levels in the skin interstitial fluid, (2) exercise-induced sweating is associated with baseline GH in skin interstitial fluid and blood, as well as exercise-induced increases in blood GH and IGF-1, and (3) cutaneous vasodilation during exercise is not associated with GH and IGF-1 in skin interstitial fluid and blood.

Inverse association between obesity and aortic pressure augmentation is attenuated in women: the Wakuya study.

OBJECTIVE: Pressure wave reflection predicts cardiovascular events in the general population. Obesity is negatively associated with pressure wave reflection. Muscular arterial diameter (responsible for pressure wave reflection) increases with obesity, and obesity-dependent dilation of muscular arteries is attenuated in women compared with men. We investigated the sex differences in the cross-sectional relationship between obesity and pressure wave reflection in a general population cohort. METHODS: Tonometric pressure waveforms were recorded in 928 adults (mean age, 56 ±â€Š10 years) to estimate the aortic augmentation index. The BMI was calculated using height and body weight, and waist circumference was recorded at the umbilical level. RESULTS: Aortic augmentation index was significantly higher in women than in men. Indices of obesity (BMI and waist circumference) were negatively correlated with the aortic augmentation index in both men and women, even after adjusting for mean arterial pressure (both P  < 0.001). Sex and BMI had no synergistic effect on the aortic augmentation index. However, when waist circumference was substituted for BMI, sex and waist circumference had a reciprocal influence on decreasing the aortic augmentation index independent of age, mean arterial pressure, diabetes, and hyperlipidemia (interaction, P  = 0.045). CONCLUSION: The negative correlation between overweight/obesity and aortic pressure augmentation from peripheral wave reflection is inhibited in women more than in men. Sex differences in aortic pressure augmentation are greater in individuals with central (abdominal) obesity than in those with general obesity.

Being overweight worsens the relationship between urinary sodium excretion and albuminuria: the Wakuya study.

BACKGROUND/OBJECTIVES: (Micro)albuminuria (a manifestation of renal microvascular damage) is an independent predictor of mortality risk, even when the urinary albumin/creatinine ratio is ≥ 10 mg/g in the general population. Excessive sodium intake and obesity are strong predictors of cardiovascular disease. However, the effect of obesity on the relationship between sodium intake and albuminuria is not fully understood. SUBJECTS/METHODS: The purpose of the present study was to investigate the cross-sectional relationships among dietary sodium intake, obesity, and albuminuria in a general population cohort. Subjects were 928 apparently healthy adults. Body mass index was calculated using the height and body weight. Urinary sodium/creatinine and albumin/creatinine ratios were measured in spot urine samples. Estimated 24-h urinary sodium/creatinine ratio (e24UNa/Cr) was assessed using age, height, body weight, and spot urinary sodium/creatinine ratio. RESULTS: Both the body mass index and e24UNa/Cr positively correlated with the urinary albumin/creatinine ratio (both, P < 0.001), and had a synergistic effect on increasing urinary albumin/creatinine ratio independent of age, sex, mean arterial pressure, and diabetes (interaction P = 0.04). When subjects were divided into 6 groups according to the tertiles of e24UNa/Cr and body mass index < (normal-weight) or ≥ 25 (overweight), the prevalence rate of urinary albumin/creatinine ratio ≥ 10 mg/g increased with rising e24UNa/Cr and being overweight (P < 0.001). CONCLUSION: An increase in body mass index increases the positive association between urinary sodium excretion and (micro)albuminuria in the general population. Excess sodium intake may strengthen cardiovascular risk by increasing (micro)albuminuria, particularly in overweight individuals.

Eccentric exercise improves myocardial oxygen supply/demand balance with decelerating aortic diastolic pressure decay: The acute and chronic studies.

Both eccentric (ECC) and concentric (CON) exercises improve energy expenditure and blood lipid profile. Although ECC exercise has a more beneficial effect on these factors than CON exercise, its benefits on vital organs are still unclear. This study investigated the mode-of-action-dependent effects on myocardial perfusion index. Seventeen healthy men (age: 26 ± 5 years) were randomly enrolled in CON (n = 9) and ECC (n = 8) groups. Transient exercise and regular training (three-day a week for 4-week) included bicep curl comprising 5-set of 10-repetition, each using 75% one-repetition maximum concentric loading. The ECC group performed one-repetition of ECC for 3-s and CON for 1-s, while the CON group performed one-repetition of CON for 3-s and ECC for 1-s. All participants were assessed for subendocardial viability ratio (SEVR, myocardial perfusion index) and aortic diastolic pressure decay. Before study, these were found to be same for both groups. Transient (ΔSEVR: 20.3 ± 13.3%, p = 0.01; Δdecay: -0.07 ± 0.02 s-1, p < .001) and regular (ΔSEVR: 18.5 ± 12.8%, p = .001; Δdecay: -0.06 ± 0.05 s-1, p = .004) ECC (but not CON) exercises significantly increased SEVR and decelerated decay. Increased SEVR with ECC exercise was associated with decelerated decay (transient ECC: r2 = 0.56, 95% confidence interval [CI] = -0.95 to -0.10, p = .03; regular ECC: r2 = 0.53, 95% CI = -0.95 to -0.05, p = .04). These findings suggest that ECC exercise improves myocardial perfusion and diastolic pressure contour is involved in physiological mechanisms.

Sports activities at a young age decrease hypertension risk-The J-Fit+ study.

This study aimed to assess (1) blood pressure between young, current athletes, and non-athletes early in life; (2) hypertension prevalence between former athletes and the general population later in life; and (3) understand the mechanisms between exercise training and hypertension risks in the form of DNA methylation. Study 1: A total of 354 young male participants, including current athletes, underwent blood pressure assessment. Study 2: The prevalence of hypertension in 1269 male former athletes was compared with that in the Japanese general population. Current and former athletes were divided into three groups: endurance-, mixed-, and sprint/power-group. Study 3: We analyzed the effect of aerobic- or resistance-training on DNA methylation patterns using publicly available datasets to explore the possible underlying mechanisms. In young, current athletes, the mixed- and sprint/power-group exhibited higher systolic blood pressure, and all groups exhibited higher pulse pressure than non-athletes. In contrast, the prevalence of hypertension in former athletes was significantly lower in all groups than in the general population. Compared to endurance-group (reference), adjusted-hazard ratios for the incidence of hypertension among mixed- and sprint/power-group were 1.24 (0.87-1.84) and 1.50 (1.04-2.23), respectively. Moreover, aerobic- and resistance-training commonly modified over 3000 DNA methylation sites in skeletal muscle, and these were suggested to be associated with cardiovascular function-related pathways. These findings suggest that the high blood pressure induced by exercise training at a young age does not influence the development of future hypertension. Furthermore, previous exercise training experiences at a young age could decrease the risk of future hypertension.

Body height determines carotid stiffness following resistance exercise in young Japanese men.

Height is inversely associated with an increase in arterial stiffness after habitual resistance exercise (RE). Considering that RE is performed during exercise prescriptions, the association between height and the acute effects of RE on arterial stiffness should be clarified. We investigated the effects of height on arterial stiffness following transient RE. Thirty-nine young Japanese men were studied under parallel experimental conditions [sham control (seated rest) and RE (5 sets of 10 repetitions at 75% of one-repetition maximum)], which were randomly ordered on two separate days. The subjects were divided into tertiles of height (each group, n = 13). The ß-stiffness index (index of arterial stiffness), assessed by carotid pulse pressure and distension, was measured in all subjects. A significant interaction between time, height, and RE was found for the ß-stiffness index (P = 0.01). RE significantly increased the ß-stiffness index in the lower-height group (P < 0.001), but not in the middle- and higher-height groups. Height was negatively associated with an increase in ß-stiffness index following RE, even after controlling the confounders, including exercise volume and changes in heart rate and carotid pulse pressure (P = 0.003). The mediation analysis demonstrated a mediating effect of carotid distension on the relationship between height and changes in the ß-stiffness index. These results suggest that short height individuals have increased arterial stiffness following RE due to decreased mechanical distension, rather than through the widening of pulsatile pressure.

Aortic diastolic pressure decay explains sex-related differences in the subendocardial viability ratio: the Wakuya study.

OBJECTIVE: Coronary heart disease is the leading cause of mortality in women. Despite a higher risk of heart failure after the first myocardial infarction in women compared with men, the sex-specific mechanisms are unknown. We hypothesized that myocardial ischemia is attributable to sex-related diastolic alterations in the central hemodynamics. METHODS: We investigated the subendocardial viability ratio (myocardial oxygen supply/demand) and aortic diastolic pressure decay index in 962 apparently healthy adults (mean age, 56 ±â€Š10 years). Using noninvasive applanation tonometry, the subendocardial viability ratio, aortic diastolic pressure decay index, and aortic augmentation index were estimated in all participants. The aortic diastolic pressure decay index was quantified by fitting an exponential curve: P(t) = P0e-λt (λ, decay index; P0, end-systolic pressure; t, time from end-systole). RESULTS: Women showed a significantly higher aortic diastolic pressure decay index, even after adjusting for age, hypercholesterolemia, and diabetes, and a significantly lower subendocardial viability ratio than men (P < 0.001). Analysis demonstrated a mediating effect of the aortic decay index on the sex-related differences in the subendocardial viability ratio (71%), despite different effects of the augmentation index (5%). CONCLUSION: These results suggest that the predisposition of women to coronary heart disease is more likely attributable to impaired myocardial perfusion caused by accelerated aortic diastolic pressure decay, rather than increased myocardial load due to augmented aortic systolic pressure.

Stature is negatively associated with increased arterial stiffness after high-intensity bicep curls training in young Japanese men.

Reports have indicated that high-intensity resistance training (RT) increases or does not change arterial stiffness. Meanwhile, higher stature has been suggested to have a protective effect on cardiovascular disease and arterial stiffness. Stature could explain the disagreement in the reported effects of RT on arterial stiffness. This study was aimed at investigating whether stature is related to RT-induced change in arterial stiffness. Thirty-six young Japanese men were assigned to the control (n = 15) and training groups (n = 21). RT programme consisted of supervised bicep curls 3 days per week for 4 weeks (5 sets of 10 repetitions at 75% of 1-repetition maximum). Arterial compliance (AC) and ß-stiffness index (via combination of ultrasound and carotid pressure waveforms) were measured in all participants. To verify the effect of stature on RT-induced change in arterial stiffness, the training group was divided into tertiles of stature: lower, middle, and higher stature groups (each group, n = 7). RT significantly decreased AC and increased ß-stiffness index in only the lower stature group (both, P < 0.05). Moreover, stature was positively associated with decreased AC and negatively associated with increased ß-stiffness index, even after adjusting for confounders including changes in relative strength, pulse pressure, and arterial distension (P < 0.05). The present results suggest that short stature contributes to the increase in arterial stiffness induced by RT in young Japanese men. The present findings suggest that stature should be taken into consideration when designing/engaging in RT programme, due to potential implications for cardiovascular health. HighlightsParticipants were divided into 3 groups according to tertiles of statures, and arterial stiffness of lower stature group (range of stature: 161.0-169.8 cm) increased after resistance training in young Japanese men, but not middle and higher stature group.Stature was negatively associated with the changed arterial stiffness by resistance training.This study suggests that short stature contributes to the elevation in arterial stiffness elicited by resistance training.

Central-to-peripheral stiffness gradients determine diastolic pressure and flow fluctuation waveforms: time domain analysis of femoral artery pulse.

OBJECTIVE: Blood pressure fluctuates during diastole to create a dicrotic wave but the mechanistic origin remains poorly understood. We sought to investigate the characteristics and determinants of diastolic pressure and flow fluctuations with a focus on stiffness gradients between the central aorta and peripheral arteries. METHODS: Using applanation tonometry and duplex ultrasound, pulse waveforms were recorded on the femoral artery in 592 patients (age: 55 ±â€Š14 years) to estimate the diastolic pressure fluctuation as a residual wave against the mono-exponential decay and the diastolic flow fluctuation as a bidirectional (forward and reverse) velocity wave. The radial, carotid, and dorsalis pedis pressures were also recorded to measure the peripheral/aortic pulse pressure (PP) and pulse wave velocity (PWV) ratios. RESULTS: There were close resemblances between the femoral pressure and flow fluctuation waveforms. The pressure and flow fluctuations were mutually correlated in relative amplitude as indexed to the total pulse height (r = 0.63), and the former temporally followed the latter. In multivariate-adjusted models, higher peripheral/aortic PP and PWV ratios were independently associated with greater pressure and flow fluctuation indices (P < 0.001). Mediation analysis revealed that the associations of PP and PWV ratios with the pressure fluctuation index were largely mediated by the flow fluctuation index [indirect/total effect ratio: 57 (95% CI 42-80)% and 54 (30-100)%, respectively]. CONCLUSION: These results suggest that central-to-peripheral pulse amplification and stiffness gradients contribute to triphasic flow fluctuations and dicrotic pressure waves. Diminished or inverted stiffness gradients caused by aortic stiffening may thus reduce diastolic runoff leading to ischemic organ damage.

Albuminuria Intensifies the Link Between Urinary Sodium Excretion and Central Pulse Pressure in the General Population: The Wakuya Study.

BACKGROUND: Central pulse pressure (cPP) is responsible for the hemodynamics of vital organs, and monitoring this parameter is important for cardiovascular disease (CVD) prevention. Excess sodium intake and (micro)albuminuria (a manifestation of renal microvascular damage) are known to be strong predictors of CVD. We sought to investigate the cross-sectional relationships among dietary sodium intake, albuminuria, and cPP in a general population cohort. METHODS: The subjects were 933 apparently healthy adults (mean age, 56 ± 10 years). Radial pressure waveforms were recorded with applanation tonometry to estimate mean arterial pressure (MAP), cPP, forward and backward pressure amplitudes, and augmentation index. The urinary sodium/creatinine and albumin/creatinine ratios were measured in spot urine samples. RESULTS: Both the urinary sodium/creatinine and albumin/creatinine ratios were positively correlated with cPP, even after adjusting for MAP (P < 0.001). Moreover, both ratios had a synergistic influence on increasing the cPP independent of age, sex, estimated glomerular filtration rate, hyperlipidemia, and diabetes (interaction P = 0.04). A similar synergistic influence was found on the forward pressure amplitude, but not on the backward pressure amplitude or augmentation index. The overall results were not altered when the urinary albumin/creatinine ratio was replaced with the existence of chronic kidney disease (CKD). CONCLUSIONS: (Micro)albuminuria strengthens the positive association between urinary sodium excretion and cPP and systolic forward pressure. Excess sodium intake may magnify the cardiovascular risk by widening the aortic pulsatile pressure, particularly in the presence of concomitant CKD.

Music attenuates a widened central pulse pressure caused by resistance exercise: A randomized, single-blinded, sham-controlled, crossover study.

Increasing central blood pressure is an independent predictor of cardiovascular disease and is an acute effect of high-intensity resistance exercise. It has been shown that classical music suppresses increased peripheral pressure during exercise. We hypothesized that classical music would suppress increased central pressure induced by high-intensity resistance exercise. To confirm this hypothesis, we examined the effect of classical music on central pressure following high-intensity resistance exercise in 18 young men. A randomized, single-blinded, sham-controlled, crossover trial was conducted under parallel experimental conditions on four separate days. The order of experiments was randomized between sham control (seated rest), music (20-min classical music track compilation), resistance exercise (5 sets of 10 repetitions at 75% of 1 repetition maximum), and resistance exercise with music conditions. Aortic pressure was measured in all subjects. No significant interaction between time, music, and resistance exercise was observed for aortic systolic pressure and diastolic pressure. In contrast, aortic pulse pressure showed a significant interaction; that is, aortic pulse pressure significantly widened after resistance exercise, whereas music significantly attenuated this widening. No significant change was observed in aortic pulse pressure in sham control and music conditions. The present findings suggest that music attenuates resistance exercise-induced increase in central pressure.

Effects of aerobic exercise training on the arterial stiffness and intramyocellular or extramyocellular lipid in overweight and obese men.

Intramyocellular lipid (IMCL) and extramyocellular lipid (EMCL) of ectopic fat in muscles are associated with arterial stiffness in normal-weight individuals. Furthermore, aerobic exercise training-induced changes in IMCL or EMCL content are related to a decrease in arterial stiffness in elderly people. Though arterial stiffness is strongly related with obesity, but the effects of aerobic exercise training on IMCL or EMCL content, with a particular focus on arterial stiffness, in obese individuals remains unclear. Here, we investigated the effects of aerobic exercise training on IMCL or EMCL content and arterial stiffness in obese individuals. First, in a cross-sectional study, we examined the relationship between arterial stiffness and IMCL or EMCL content in 24 overweight and obese men. Secondly, we investigated the effects of aerobic exercise intervention on arterial stiffness and IMCL or EMCL content in 21 overweight and obese men. In the cross-sectional study, EMCL content was positively correlated with baPWV and ß-stiffness index, whereas IMCL content was negatively correlated with baPWV. In the intervention study, there were no significant changes in baPWV, ß-stiffness index, and IMCL and EMCL contents after aerobic exercise training. However, exercise-induced change in baPWV and ß-stiffness index were positively correlated with changes in EMCL content. Moreover, the group of improvements in baPWV was only correlated significantly with reduced EMCL content. These results suggest that IMCL and EMCL contents may affect arterial stiffness in overweight and obese men.

Dietary modification reduces serum angiopoietin-like protein 2 levels and arterial stiffness in overweight and obese men.

PURPOSE: Weight loss can reduce obesity-induced arterial stiffening that is attributed to decreased inflammation. Angiopoietin-like protein 2 (ANGPTL2) is a pro-inflammatory adipokine that is upregulated in obesity and is important in the progression of atherosclerosis and cardiovascular disease. The purpose of this study is to investigate the effects of dietary modification on circulating ANGPTL2 levels and arterial stiffness in overweight and obese men. METHODS: Twenty-two overweight and obese men (with mean age of 56 ± 2 years and body mass index of 28.6 ± 2.6 kg/m2) completed a 12-week dietary modification program. We measured the arterial compliance and ß-stiffness index (as the indices of arterial stiffness) and serum ANGPTL2 levels before and after the program. RESULTS: After the 12-week dietary modification, body mass and daily energy intake were significantly reduced. Arterial compliance was significantly increased and ß-stiffness index was significantly decreased after the 12-week dietary modification program. Serum ANGPTL2 levels were significantly decreased. Also, the changes in arterial compliance were negatively correlated with the changes in serum ANGPTL2 levels, whereas the changes in ß-stiffness index were positively correlated with the changes in serum ANGPTL2 levels. CONCLUSION: These results suggest that the decrease in circulating ANGPTL2 levels can be attributed to the dietary modification-induced reduction of arterial stiffness in overweight and obese men.

Aortic diastolic pressure decay modulates relation between worsened aortic stiffness and myocardial oxygen supply/demand balance after resistance exercise.

High-intensity resistance exercise (RE) increases aortic stiffness and decreases the index of myocardial oxygen supply/demand balance (Buckberg index, BI); there is a correlation between the changes in these parameters. Central hemodynamics during diastole can explain the correlation. We aimed to investigate whether the aortic diastolic decay index mediates the association between changes in aortic stiffness and BI by high-intensity RE. We evaluated the effect of high-intensity RE on aortic stiffness, BI, aortic decay index, and their associations in 52 young men. Subjects were studied under parallel experimental conditions on two separate days. The order of experiments was randomized between RE (5 sets of 10 repetitions at 75% of 1-repetition maximum) and sham control (seated rest). Aortic pulse wave velocity (PWV; index of aortic stiffness), BI, and aortic decay index were measured in all subjects. Aortic decay index was quantified by fitting an exponential curve: P(t) = P0e-λt (where λ is decay index, P0 is end-systolic pressure and t is time from end-systole). Aortic PWV and decay index increased and BI decreased after RE. RE conditions showed that change in the aortic decay index was associated with changes in aortic PWV and changes in aortic PWV were related to changes in BI, although the PWV-BI relationship was not significant after accounting for decay index change. Mediation analysis revealed the mediating effect of the aortic decay index on the relationship between changes in aortic PWV and BI. The present findings suggest that high-intensity RE-induced aortic stiffening worsens myocardial viability by accelerating aortic diastolic exponential decay.NEW & NOTEWORTHY Aortic pulse wave velocity (PWV) and diastolic decay index increased and Buckberg index (BI) decreased after resistance exercise (RE). Mediation analysis revealed a mediating effect of aortic decay index on the relationship between changes in aortic PWV and BI. The present study provides evidence that high-intensity RE-induced aortic stiffening accelerates aortic decay and aortic decay can account for the relationship between aortic stiffening and a deteriorated surrogate marker of myocardial oxygen supply/demand balance induced by high-intensity RE.

Role of High Physical Fitness in Deterioration of Male Sexual Function in Japanese Adult Men.

Male sexual function is regulated by vascular function and impaired vascular function is closely related with erectile dysfunction (ED). Vascular functions are positively influenced by physical fitness (i.e., aerobic capacity, muscle strength, and flexibility). The detailed associations between physical fitness and male sexual function remain poorly understood. The present study aimed to clarify the influence of physical fitness on male sexual function. In 177 adult men, peak oxygen consumption (VO2 peak), handgrip strength (HGS), and sit and reach were measured as indices of physical fitness. Arterial stiffness and erectile function were assessed by carotid-femoral pulse wave velocity (cfPWV) and the International Index of Erectile Function 5 (IIEF5) questionnaire, respectively. IIEF5 score was significantly correlated with VO2 peak ( rs = 0.52), HGS ( rs = 0.37), and cfPWV ( rs = -0.44); and multivariate linear regression analyses showed that VO2 peak, HGS, and cfPWV were significantly associated with IIEF5 score after considering confounders. The receiver operator characteristic curve analysis suggested that the cutoff values for predicting ED were 29.0 ml/min/kg for VO2 peak and 39.3 kg for HGS. The IIEF5 score was the highest in the subjects with the values of both VO2 peak and HGS were higher than their respective cutoff values, while the IIEF5 score was the lowest in the subjects with the values of both VO2 peak and HGS were lower than their respective cutoff values. These results suggest that the maintenance of high aerobic capacity and muscular strength may offset deterioration of male sexual function.

Central artery stiffness is related to cerebral oxygenation hemodynamics during executive function tasks in healthy middle-aged and older adults.

Age-related decreases in cognitive function, cerebral perfusion, and vascular function increase the risk of dementia. However, the effects of central artery stiffness on cerebral oxygenation hemodynamics during executive function tasks and executive function remain unclear. The aim of this cross-sectional study was to investigate the relationships among central artery stiffness, cerebral oxygenation hemodynamics during executive function tasks, and executive function in middle-aged and older adults. Sixty-two middle-aged and older adults (age range: 51-79 years) were recruited for this study. For each participant, we measured the carotid artery ß-stiffness, oxygenated hemoglobin (oxy-Hb) signal change in the prefrontal cortex during the Stroop task, and Stroop interference time. Correlation analyses revealed that the carotid artery ß-stiffness was significantly correlated with the Stroop interference time (r = 0.43, P < 0.001) and with the oxy-Hb signal change in the left (r = -0.38, P = 0.002), but not the right, prefrontal cortex. In addition, the Stroop interference time was significantly correlated with the oxy-Hb signal change in the left (r = -0.42, P = 0.001), but not the right, prefrontal cortex. The participants were divided into the low and high arterial stiffness groups according to the median value. We found that the Stroop interference time was significantly shorter (P = 0.006) and the oxy-Hb signal change in the left prefrontal cortex was significantly larger in the low arterial stiffness group than in the high arterial stiffness group (P = 0.011). In the low, but not the high, arterial stiffness group, the oxy-Hb signal change of the left prefrontal cortex during executive function tasks was significantly larger than the oxy-Hb signal change of the right prefrontal cortex (P = 0.014). These results suggest that increases in central artery stiffness are associated with decreases in oxygenation hemodynamics in the left prefrontal cortex during executive function tasks and reductions in executive function.

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.

Lactotripeptides Supplementations Alleviate the Decrease in Maximal Isometric Force After High-Intensity Eccentric Exercise: A Randomized, Placebo-Controlled, Double-Blind Clinical Trial.

OBJECTIVE: The aim of the study was to investigate whether lactotripeptides supplementations alleviate the decrease in the maximal isometric force, an indirect marker of muscle damage, after eccentric exercise (ECC). DESIGN: Twenty-two young men performed 50 ECC of the elbow flexors using an isokinetic dynamometer. The subjects were randomly assigned to either the placebo or lactotripeptides group and were each given a 4.5 mg/d placebo or lactotripeptides thrice on the exercise day and the day after. Maximal isometric force and brachial arterial diameter were assessed before and 2 days after the ECC. RESULTS: The interaction of time and group on maximal isometric force was significant (P < 0.05); maximal isometric force was significantly decreased in both groups after ECC (P < 0.005). The interaction of brachial arterial diameter was significant (P < 0.05); brachial arterial diameter was significantly increased in only the lactotripeptides group (P < 0.005). In addition, the change in maximal isometric force was significantly related to the change in brachial arterial diameter after adjusting for body weight and change in range of motion (P < 0.05). CONCLUSIONS: The present results suggest that lactotripeptides supplementation alleviates the decrease in the maximal isometric force via an increase in brachial arterial diameter after ECC.

Resistance training-induced decrease in central arterial compliance is associated with decreased subendocardial viability ratio in healthy young men.

High-intensity resistance training decreases central arterial compliance (CAC). Subendocardial viability ratio (SEVR) is a useful tool that reflects the balance between coronary perfusion and left ventricular afterload. Animal studies have demonstrated that decreased CAC is associated with SEVR deterioration. Therefore, resistance training-induced decrease in CAC may be associated with changes in SEVR. The objective of the present study was to investigate the association between SEVR and CAC using both cross-sectional and longitudinal (i.e., resistance training) study designs. To achieve this, we first conducted a cross-sectional study to investigate the association between SEVR and CAC in 89 young men. Thereafter, a longitudinal study was performed to examine the effects of resistance training on SEVR and CAC in young men. A total of 28 young men were divided into 2 groups: control (n = 13) and training (n = 15). In the training group, subjects underwent supervised resistance training for 4 weeks (5 sets of 10 repetitions at 75% of 1-repetition maximum, 3 times/week). CAC and SEVR were then measured in all subjects. In the cross-sectional study, SEVR was significantly positively correlated with CAC, whereas resistance training significantly decreased both SEVR and CAC. Moreover, training-induced changes in CAC were significantly correlated with changes in SEVR. Thus, these results suggest that resistance training-induced decrease in CAC is associated with decreased SEVR in young men.