Toshiya Nagamatsu

Prospective Study of Physical Activity and Sleep in Middle-Aged and Older Adults

INTRODUCTION Few prospective cohort studies have examined the association between physical activity (PA) and insomnia prevention, and the effective PA intensity remains unclear. This prospective study explores how PA intensity prevents incident short sleep duration and subjective insufficient sleep in middle-aged and older adults. METHODS A self-reported questionnaire gathered data on sleep and PA variables, including moderate low-intensity PA (MLPA); moderate high-intensity PA (MHPA); and vigorous-intensity PA (VPA), during health checkups conducted in Meiji Yasuda Shinjuku Medical Center in Tokyo. This study followed two cohorts from a 2008 baseline survey: (1) participants free of short sleep duration (n=7,061) and (2) participants free of insufficient sleep (n=7,385). They were divided into middle-aged (<60 years; 45.7 [8.8] years for sleep duration and 45.5 [8.8] years for sleep sufficiency) and older adults (both groups aged 65.3 [4.7] years) and followed for a mean 3.4 years until 2013. Data were analyzed in 2014. RESULTS Engaging in MHPA (hazard ratio [HR]=0.81, 95% CI=0.67, 0.98) and VPA (HR=0.83, 95% CI=0.71, 0.97) had a significant preventive effect on incident subjective insufficient sleep among middle-aged adults. For older adults, only MLPA (HR=0.58, 95% CI=0.42, 0.81) had a significant preventive effect on incident insufficient sleep, and PA did not significantly affect incident short sleep duration. CONCLUSIONS Middle-aged adults engaging in MHPA and VPA and older adults engaging in MLPA can effectively maintain sleep sufficiency. When providing an effective PA program to prevent insomnia, the intensity of PA should correspond to the participants age.

Physical activity and risk of fatty liver in people with different levels of alcohol consumption: a prospective cohort study

Objective To investigate whether physical activity affects the future incidence of fatty liver in people with never-moderate and heavy alcohol consumption. Design Prospective cohort study. Setting Health check-up programme at Meiji Yasuda Shinjuku Medical Center in Shinjuku Ward, Tokyo, Japan. Population A total of 10 146 people aged 18 years or older without fatty liver enrolled through baseline surveys conducted from 2005 to 2007. They were grouped into never-moderate alcohol drinkers (n=7803) and heavy alcohol drinkers (n=2343) and followed until 2013. Main outcome measure Incident fatty liver diagnosed by ultrasound. Results During a mean follow-up of 4.4 years (34 648 person-years), 1255 never-moderate alcohol drinkers developed fatty liver; 520 heavy alcohol drinkers developed fatty liver during a mean follow-up of 4.1 years (9596 person-years). For never-moderate alcohol drinkers, engaging in >3×/week of low-intensity (HR=0.82, 95% CI 0.71 to 0.96) and moderate-intensity (HR=0.56, 95% CI 0.39 to 0.81) physical activity significantly reduced incident fatty liver compared with those who engaged in physical activity <1×/week. For vigorous-intensity physical activity, frequencies of 2×/week (HR=0.57, 95% CI 0.38 to 0.86) and >3×/week (HR=0.55, 95% CI 0.38 to 0.79) were significantly associated with lower risk of incident fatty liver. In propensity-adjusted models, these significant associations still remained. By contrast, in heavy alcohol drinkers, there were no significant associations between the type or frequency of physical activity and incident fatty liver. Conclusions Physical activity had an independent protective effect on incident fatty liver only in the never-moderate alcohol drinkers, and the preventive effect increased with higher frequencies and intensities of physical activity.

Effects of stretching on menopausal and depressive symptoms in middle-aged women: a randomized controlled trial

Objective:Exercise may help alleviate menopausal and depressive symptoms in middle-aged women, but sufficient evidence does not currently exist to fully support this theory. Whereas frequent moderate- to vigorous-intensity exercise may be associated with the risk of menopausal hot flashes, light-intensity exercise, such as stretching, is not likely to increase the occurrence of hot flashes. Little is, however, known about the effects of light-intensity exercise on menopausal and depressive symptoms. We examined the effects of a 3-week stretching program on the menopausal and depressive symptoms in middle-aged, Japanese women. Methods:Forty Japanese women, aged 40 to 61 years, were recruited (mean age, 51.1 ± 7.3 y). The participants were randomly assigned to either a stretching or a control group. The stretching group (n = 20) participated in a 3-week intervention program that involved 10 minutes of daily stretching, just before bedtime. The control group (n = 20) was assigned to a waiting list. Menopausal symptoms were evaluated using the Simplified Menopausal Index, which measures vasomotor, psychological, and somatic symptoms. Depressive symptoms were assessed using the Self-Rating Depression Scale. Results:The compliance rate was 75.8% during the 3-week intervention program. The total Simplified Menopausal Index scores, including the vasomotor, psychological, and somatic symptoms, and the Self-Rating Depression Scale scores significantly decreased in the stretching group compared with that in the control group. No adverse events, including increased hot flashes, were reported by the participants during the study period. Conclusions:These findings suggest that 10 minutes of stretching before bedtime decreases menopausal and depressive symptoms in middle-aged, Japanese women.

Impact of physical activity on nonalcoholic steatohepatitis in people with nonalcoholic simple fatty liver: A prospective cohort study.

Preventing nonalcoholic simple fatty liver (NASFL) from progressing to nonalcoholic steatohepatitis (NASH) is a key to avoiding cirrhosis. Physical activity (PA) may help manage fatty liver; however, there is a lack of prospective studies showing an association between PA and NASH. Our current prospective study investigated whether PA prevents NASFL from progressing to NASH. Study data were obtained from the health check-up program of Meiji Yasuda Shinjuku Medical Center in Tokyo, Japan. From a baseline survey between 2005 and 2007, 1149 people with NASFL met eligibility criteria including low alcohol consumption. We followed participants until 2014 assessing liver status via ultrasound and liver enzyme levels, including alanine aminotransferase (ALT) and aspartate aminotransferase (AST). We classified participants with fatty liver and higher levels of either ALT or AST as having NASH. Through a self-reported questionnaire, we classified PA into three intensities: moderate low-intensity PA (MLPA, 3-5 METs), moderate high-intensity PA (MHPA, 5-7 METs), and vigorous-intensity PA (VPA, ≥7 METs). During a mean follow-up of 4.2years (4804person-years), 318 of the 1149 participants (27.7%) progressed from NASFL to NASH. A multivariate-adjusted Cox model showed a significant preventive effect of VPA on progression to NASH (HR=0.55, 95% CI=0.32-0.94) and no significant associations between MLPA (HR=1.01, 95% CI=0.79-1.30) or MHPA (HR=0.97, 95% CI=0.66-1.42) and progression to NASH. Only VPA prevented NASFL from progressing to NASH; MLPA and MHPA had no preventive effect on NASH. Higher intensity PA may be needed to manage NASH.