Blood flow restriction accelerates aerobic training-induced adaptation of [Formula: see text] kinetics at the onset of moderate-intensity exercise.

It is unclear whether blood flow restriction (BFR) accelerates the adaptation of the time constant (τ) of phase II oxygen uptake ([Formula: see text]) kinetics in the moderate-intensity exercise domain via moderate-intensity aerobic training. Therefore, healthy participants underwent moderate-intensity [45-60% [Formula: see text] Reserve] aerobic cycle training with or without BFR (BFR group, n = 9; CON group, n = 9) for 8 weeks to evaluate [Formula: see text] kinetics during moderate-intensity cycle exercise before (Pre) and after 4 (Mid) and 8 (Post) weeks of training. Both groups trained for 30 min, 3 days weekly. BFR was performed for 5 min every 10 min by applying cuffs to the upper thighs. The τ significantly decreased by Mid in the BFR group (23.7 ± 2.9 s [Pre], 15.3 ± 1.8 s [Mid], 15.5 ± 1.4 s [Post], P < 0.01) and by Post in the CON group (27.5 ± 2.0 s [Pre], 22.1 ± 0.7 s [Mid], 18.5 ± 1.9 s [Post], P < 0.01). Notably, the BFR group's τ was significantly lower than that of the CON group at Mid (P < 0.01) but not at Post. In conclusion, BFR accelerates the adaptation of the [Formula: see text] kinetics of phase II by moderate-intensity aerobic training.

Aging exaggerates blood pressure response to ischemic rhythmic handgrip exercise in humans.

Ischemic skeletal muscle conditions are known to augment exercise-induced increases in blood pressure (BP). Aging is also a factor that enhances the pressor response to exercise. However, the effects of aging on the BP response to ischemic exercise remain unclear. We, therefore, tested the hypothesis that aging enhances the BP response to rhythmic handgrip (RHG) exercise during postexercise muscle ischemia (PEMI). We divided the normotensive participants without cardiovascular diseases into three age groups: young (n = 26; age, 18-28 years), middle-aged (n = 23; age, 35-59 years), and older adults (n = 23; age, 60-80 years). The participants performed RHG exercise with minimal effort for 1 min after rest with and without PEMI, which was induced by inflating a cuff on the upper arm just before the isometric handgrip exercise ended; the intensity was 30% of maximal voluntary contraction force. Under PEMI, the increase in diastolic BP (DBP) from rest to RHG exercise in the older adult group (Δ13 ± 2 mmHg) was significantly higher than that in the young (Δ5 ± 2 mmHg) and middle-aged groups (Δ6 ± 1 mmHg), despite there being no significant difference between the groups in the DBP response from rest to RHG exercise without PEMI. Importantly, based on multiple regression analysis, age remained a significant independent determinant of both the SBP and DBP responses to RHG exercise during PEMI (p < 0.01). These findings indicate that aging enhances the pressor response to ischemic rhythmic exercise.

Exaggerated pressor response to blood flow restriction resistance exercise is associated with a muscle metaboreflex-induced increase in blood pressure in young, healthy humans.

Some researchers are concerned that exercise training with the blood flow restriction (BFR) technique induces an exaggeration in blood pressure response and potentiates adverse cardiovascular events. In the present study, we demonstrate that the blood pressure response to arm-curl exercise was intensified by the BFR technique, and the degree of intensification was associated with a blood pressure response to postexercise muscle ischemia of the elbow flexors, which elicit a muscle metaboreflex. Novelty: BFR technique intensifies blood pressure response to exercise, which was associated with a blood pressure response in postexercise muscle ischemia-induced muscle metaboreflex.

Breath isoprene excretion during rest and low-intensity cycling exercise is associated with skeletal muscle mass in healthy human subjects.

The physiological roles of isoprene, which is one of the many endogenous volatile organic compounds contained in exhaled breath, are not well understood. In recent years, exhaled isoprene has been associated with the skeletal muscle. Some studies have suggested that the skeletal muscle produces and/or stores some of the isoprene. However, the evidence supporting this association remains sparse and inconclusive. Furthermore, aging may affect breath isoprene response because of changes in the skeletal muscle quantity and quality. Therefore, we investigated the association between the breath isoprene excretion ([Formula: see text]) and skeletal muscle mass in young (n = 7) and old (n = 7) adults. The participants performed an 18 min cycling exercise after a 3 min rest. The workload corresponded to an intensity of 30% of the heart rate reserve, as calculated by the Karvonen formula. The exhaled breath of each participant was collected during the exercise test. We calculated [Formula: see text] from the product minute ventilation and isoprene concentration and, then, investigated the relationships between [Formula: see text] and muscle mass, which was measured by multi-frequency bioelectrical impedance analysis. Importantly, muscle mass persisted as a significant determinant that explained the variance in [Formula: see text] at rest even after adjusting for age. Furthermore, the muscle mass was a significant determinative factor for [Formula: see text] response during exercise, regardless of age. These data indicated that skeletal muscle mass could be one of the determinative factors for [Formula: see text] during rest and response to exercise. Thus, we suggest that the skeletal muscle may play an important role in generating and/or storing some of the endogenous isoprene. This new knowledge will help to better understand the physiological functions of isoprene in humans (Approval No. 20190079).

Sociodemographic determinants of pedometer-determined physical activity among Japanese adults.

BACKGROUND: Although previous studies have reported physical activity and its sociodemographic determinants using self-report measures, there have been few studies using pedometers. PURPOSE: To ascertain pedometer-determined physical activity and its sociodemographic determinants among community residents living in four Japanese cities. METHODS: A cross-sectional mail survey was conducted from February 2007 to January 2008 with a sample of 4000 residents (aged 20-69 years and 50% male) who were randomly selected from the registry of residential addresses. Complete responses for both questionnaire and pedometer were obtained from 790 residents (48.3±13.7 years, 46.7% male). Associations of 11 sociodemographic variables with steps per day were examined using multiple logistic regression analyses. Data were analyzed in 2010. RESULTS: Men averaged 8763±3497 steps/day and women averaged 8242±3277 steps/day. Further, 29.0% of men and 27.8% of women walked ≥10,000 steps/day. City of residence, good self-rated health, low educational attainment, and not owning a car were associated with taking ≥10,000 steps/day in men, whereas employed status and dog ownership were associated with walking ≥10,000 steps/day in women. CONCLUSIONS: The results contribute to understanding of step-defined physical activity and its sociodemographic determinants. A diversity of step counts by sociodemographic variables clarifies specific populations among Japanese who are in need of intervention to promote physical activity.

Association between perceived neighborhood environment and walking among adults in 4 cities in Japan.

BACKGROUND: Recent research highlights the importance of environment as a determinant of physical activity; however, evidence among Japanese is sparse. The aim of this study was to examine the association between perceived neighborhood environment and neighborhood walking for multiple purposes among Japanese. METHODS: We conducted a population-based, cross-sectional study of 1461 Japanese adults (age: 48.2 +/- 14.1 years, men: 44.8%). Neighborhood environment and walking were assessed by a validated questionnaire. The odds ratio of active walkers was calculated in relation to environmental characteristics after adjustment for age, sex, and other potential confounders. RESULTS: Participants were more likely to walk when they perceived that there was high residential density (odds ratio, 1.47; 95% confidence interval, 1.11-1.96), fair land use mix-diversity (1.37, 1.04-1.81), good walking/cycling facilities (1.56, 1.19-2.04), and attractive aesthetics (1.49, 1.14-1.95). Environmental factors associated with walking differed with respect to the purpose for walking. The environmental characteristics associated with walking for daily errands and with walking for commuting were similar, and included residential density and land use mix. Walking for leisure was associated with walking/cycling facilities, aesthetics, and traffic safety. Stratified analyses showed some sex-specific associations. Among women, there was an unexpected inverse association of leisure walking with both residential density and land use mix-diversity. CONCLUSIONS: The association between neighborhood environment and walking differed by walking purpose. The results were generally consistent with those of studies conducted in Western countries, except for the association of high residential density and good land use mix-diversity with less leisure walking in women. These results suggest possible targets for environmental interventions to promote walking.

Sociodemographic variation in the perception of barriers to exercise among Japanese adults.

BACKGROUND: The perception of barriers to exercise is an important correlate of exercise participation. However, only a limited number of studies-mostly from Western countries-have attempted to describe the perceptions of barriers to exercise in specific population groups. This study examined the associations between sociodemographic attributes and perceived barriers to exercise in Japanese adults. METHODS: A population-based cross sectional study of 865 participants (age: 20-69 years old, men: 46.5%) was conducted in 4 cities in Japan. Nine sociodemographic attributes (sex, age, location of residence, educational attainment, marital status, employment status, presence of dependents in the household, self-rated health, body mass index), along with exercise frequency and perception of barriers to exercise (discomfort, lack of motivation, lack of time, lack of social support, poor environment) were assessed by self-administered questionnaire. RESULTS: The most strongly perceived barrier was lack of time. Five of 9 sociodemographic attributes were significantly related to certain types of perceived barriers. Participants who more strongly perceived barriers were younger, more highly educated, more likely to be employed, and had relatively poor self-rated health and a high BMI. The specific types of barriers that were strongly perceived varied with the sociodemographic attributes of the participants. CONCLUSIONS: The results show that the perception of barriers to exercise varies among specific population groups, which indicates the importance of targeting exercise promotion strategies to specific populations.