Hiroyuki Sasai

Dr. Hiroyuki Sasai

orcid

Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2009 in Journal of Applied Physiology
Verified
Journal Article
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MKMaeng-Kyu Kim
Maeng-Kyu Kim
TTTsugio Tomita
Tsugio Tomita
MKMi-Ji Kim
Mi-Ji Kim
HSHiroyuki Sasai
Hiroyuki Sasai
SMSeiji Maeda
Seiji Maeda
KTKiyoji Tanaka
Kiyoji Tanaka
The purpose of this study was to determine the effects of exercise training on ventricular epicardial fat thickness in obese men and to investigate the relationship of the change in epicardial fat thickness to changes in abdominal fat tissue following exercise training. Twenty-four obese middle-aged men [age, 49.4 ± 9.6 yr; weight, 87.7 ± 11.2 kg; body mass index (BMI), 30.7 ± 3.3 kg/m2; peak oxygen consumption, 28.4 ± 7.2 ml·kg−1·min−1; means ± SD] participated in this study. Each participant completed a 12-wk supervised exercise training program (60–70% of the maximal heart rate; 60 min/day, 3 days/wk) and underwent a transthoracic echocardiography. The epicardial fat thickness on the free wall of the right ventricle was measured from both parasternal long- and short-axis views. The visceral adipose tissue (VAT) and subcutaneous adipose tissues were measured by computed tomography. Following exercise training, the epicardial fat thickness was significantly decreased ( P < 0.001). The percentage change of epicardial fat thickness was twice as high compared with those of waist, BMI, and body weight of original values ( P <0.05). There was a significant relationship ( r = 0.525, P = 0.008) between changes in the epicardial fat thickness and VAT with exercise training. Stepwise multiple regression analysis revealed that the change in VAT, change in systolic blood pressure, and change in quantitative insulin sensitivity check index were independently related to the change epicardial fat thickness ( P < 0.05). The ventricular epicardial fat thickness is reduced significantly after aerobic exercise training and is associated with a decrease in VAT. These results suggest that aerobic exercise training may be an effective nonpharmacological strategy for decreasing the ventricular epicardial fat thickness and visceral fat area in obese middle-aged men.

2 August 2019 in JMIR mHealth and uHealth
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Journal Article
Open access
HMHaruka Murakami
Haruka Murakami
RKRyoko Kawakami
Ryoko Kawakami
SNSatoshi Nakae
Satoshi Nakae
Yosuke YamadaYosuke Yamada
Yosuke Yamada
Yoshio NakataYoshio Nakata
Yoshio Nakata
MMMotohiko Miyachi
Motohiko Miyachi
Background: Self-monitoring using certain types of pedometers and accelerometers has been reported to be effective for promoting and maintaining physical activity (PA). However, the validity of estimating the level of PA or PA energy expenditure (PAEE) for general consumers using wearable devices has not been sufficiently established. Objective: We examined the validity of 12 wearable devices for determining PAEE during 1 standardized day in a metabolic chamber and 15 free-living days using the doubly labeled water (DLW) method. Methods: A total of 19 healthy adults aged 21 to 50 years (9 men and 10 women) participated in this study. They followed a standardized PA protocol in a metabolic chamber for an entire day while simultaneously wearing 12 wearable devices: 5 devices on the waist, 5 on the wrist, and 2 placed in the pocket. In addition, they spent their daily lives wearing 12 wearable devices under free-living conditions while being subjected to the DLW method for 15 days. The PAEE criterion was calculated by subtracting the basal metabolic rate measured by the metabolic chamber and 0.1×total energy expenditure (TEE) from TEE. The TEE was obtained by the metabolic chamber and DLW methods. The PAEE values of wearable devices were also extracted or calculated from each mobile phone app or website. The Dunnett test and Pearson and Spearman correlation coefficients were used to examine the variables estimated by wearable devices. Results: On the standardized day, the PAEE estimated using the metabolic chamber (PAEEcha) was 528.8±149.4 kcal/day. The PAEEs of all devices except the TANITA AM-160 (513.8±135.0 kcal/day; P>.05), SUZUKEN Lifecorder EX (519.3±89.3 kcal/day; P>.05), and Panasonic Actimarker (545.9±141.7 kcal/day; P>.05) were significantly different from the PAEEcha. None of the devices was correlated with PAEEcha according to both Pearson (r=−.13 to .37) and Spearman (ρ=−.25 to .46) correlation tests. During the 15 free-living days, the PAEE estimated by DLW (PAEEdlw) was 728.0±162.7 kcal/day. PAEE values of all devices except the Omron Active style Pro (716.2±159.0 kcal/day; P>.05) and Omron CaloriScan (707.5±172.7 kcal/day; P>.05) were significantly underestimated. Only 2 devices, the Omron Active style Pro (r=.46; P=.045) and Panasonic Actimarker (r=.48; P=.04), had significant positive correlations with PAEEdlw according to Pearson tests. In addition, 3 devices, the TANITA AM-160 (ρ=.50; P=.03), Omron CaloriScan (ρ=.48; P=.04), and Omron Active style Pro (ρ=.48; P=.04), could be ranked in PAEEdlw. Conclusions: Most wearable devices do not provide comparable PAEE estimates when using gold standard methods during 1 standardized day or 15 free-living days. Continuous development and evaluations of these wearable devices are needed for better estimations of PAEE.

9 January 2019 in JMIR mHealth and uHealth
Verified
Journal Article
Open access
SAShiho Amagasa
Shiho Amagasa
MKMasamitsu Kamada
Masamitsu Kamada
HSHiroyuki Sasai
Hiroyuki Sasai
NFNoritoshi Fukushima
Noritoshi Fukushima
HKHiroyuki Kikuchi
Hiroyuki Kikuchi
SIShigeru Inoue
Shigeru Inoue
Mobile and tablet apps, ubiquitous and pervasive computing, wearable computing and domotics for health.

1 May 2016 in Circulation: Arrhythmia and Electrophysiology
Verified
Journal Article
Closed access
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JMJared W Magnani
Jared W Magnani
NWNa Wang
Na Wang
Emelia J. BenjaminEmelia J. Benjamin
Emelia J. Benjamin
MGMelissa E. Garcia
Melissa E. Garcia
DBDouglas C. Bauer
Douglas C. Bauer
THTamara B. Harris
Tamara B. Harris
Background—: Age is the foremost risk factor for atrial fibrillation (AF), and AF has a rising prevalence in older adults. How AF may contribute to decline in physical performance in older adults has had limited investigation. We examined the associations of incident AF and 4-year interval declines in physical performance at ages 70, 74, 78, and 82 years in the Health, Aging, and Body Composition (Health ABC) Study. Methods and Results—: Health ABC is a prospective cohort of community-dwelling older adults (n=3075). The study conducted serial assessments of physical performance with the Health ABC physical performance battery (scored 0–4), grip strength, 2-minute walk distance, and 400-m walking time. Incident AF was identified from the Center for Medicare and Medicaid Services and related to 4-year interval decline in physical performance. After exclusions, the analysis included 2753 Health ABC participants (52% women, 41% black race). Participants with AF had a significantly greater 4-year physical performance battery decline than those without AF at age 70, 74, 78, and 82, with mean estimated decline ranging from −0.08 to −0.10 U (95% confidence interval, −0.18 to −0.01; P <0.05 for all estimates) after multivariable adjustment. Grip strength, walk distance, and walk time similarly showed significantly greater declines at each 4-year age interval in participants with AF. Conclusions—: In community-based cohort older adults, incident AF was associated with increased risk of decline in physical performance. Further research is essential to identify mechanisms and preventive strategies for how AF may contribute toward declining physical performance in older adults.

18 October 2017 in PLOS ONE
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Journal Article
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SKSatoshi Kurita
Satoshi Kurita
SYShohei Yano
Shohei Yano
KIKaori Ishii
Kaori Ishii
ASAi Shibata
Ai Shibata
HSHiroyuki Sasai
Hiroyuki Sasai
KOKoichiro Oka
Koichiro Oka
This study aims to compare the outputs of the waist-worn Active style Pro HJA-350IT (ASP; used in studies with Asian populations), the waist-worn ActiGragh™GT3X+ using the normal filter (GT3X+) and the thigh-worn activPAL3 (AP) in assessing adults’ sedentary behaviour (total sedentary time, number of breaks) under free-living conditions. Fifty healthy workers wore the three monitors simultaneously during their waking hours on two days, including a work day and a non-work day. Valid data were at least 10 hours of wearing time, and the differences between monitors on the sedentary outputs using the AP as criterion measurement were analyzed by ANOVA. The number of participants who had complete valid data for work day and non-work day was 47 and 44, respectively. Total sedentary time and breaks estimated by the AP were respectively 466.5 ± 146.8 min and 64.3 ± 24.9 times on the work day and 497.7 ± 138.3 min and 44.6 ± 15.4 times on the non-work day. In total sedentary time, the ASP estimated 29.7 min (95%CI = 7.9 to 51.5) significantly shorter than the AP on the work day but showed no significant difference against the AP on the non-work day. The GT3X+ estimated 80.1 min (54.6 to 105.6) and 52.3 (26.4 to 78.2) significantly longer than the AP on the work day and the non-work day, respectively. For the number of breaks from sedentary time, on both days, the ASP and the GT3X+ estimated significantly more than the AP: 14.1 to 15.8 times (6.3 to 22.5) for the ASP and 27.7 to 28.8 times (21.8 to 34.8) for the GT3X+. Compared to the AP as the criterion, the ASP can underestimate total sedentary time and the GT3X+ can overestimate it, and more so at the lower levels of sedentary time. For breaks from sedentary time, compared to the AP, both the GT3X+ the ASP can overestimate.

19 November 2008 in Angiology
Verified
Journal Article
Open access
AMAsako Miyaki
Asako Miyaki
SMSeiji Maeda
Seiji Maeda
MYMutsuko Yoshizawa
Mutsuko Yoshizawa
MMMaiko Misono
Maiko Misono
YSYoko Saito
Yoko Saito
RARyuichi Ajisaka
Ryuichi Ajisaka
Obesity and reduction in central arterial distensibility, respectively, have been identified as powerful and independent risk factors for cardiovascular disease. However, the effect of weight reduction on central arterial function in obese subjects has not yet been clarified. We investigated whether low-calorie diet-induced weight reduction affects central arterial distensibility and endothelial function in middle-aged obese men. Twelve obese men (age: 45 ± 2 yrs, BMI: 30±1 kg/m 2 ) completed a 12-week dietary intervention. Caloric restriction induced significantly weight loss and decrease in BMI. After the program, carotid arterial compliance significantly increased and β-stiffness index and aortic pulse-wave velocity remarkably decreased. Concentrations of plasma endothelin-1 (ET-1) significantly decreased and plasma nitric oxide (NO) markedly increased after the program. Weight reduction by low-calorie diet in obese men increases central arterial distensibility, which may contribute to the improvement in endothelial function, as noted by a decrease in ET-1 and an increase in NO.