Dietary palmitic acid to oleic acid ratio modulates energy metabolism and biological rhythms in young healthy Japanese males.

The present study investigated the potential role of the composition of dietary fatty acids in the regulation of biological rhythms, such as the sleep architecture, core body temperature and leukocyte clock gene expression, in subjects fed meals rich in palmitic acid (PA) or oleic acid (OA). Eleven males participated in two sessions of indirect calorimetry in a whole-room metabolic chamber. In each session, subjects consumed three meals rich in PA (44·3 % of total fat as PA and 42·3 % as OA) or OA (11·7 % of total fat as PA and 59·3 % as OA) in the metabolic chamber. The ratio of PA to OA in plasma was significantly lower and fat oxidation was significantly higher during 24 h of indirect calorimetry in the session with meals rich in OA than in that with meals rich in PA. The duration of slow wave sleep (SWS) was shorter, the latency of SWS was longer and the nadir of core body temperature after bedtime was later in the session with meals rich in PA than in that with meals rich in OA. The peak in CRY1 gene expression was earlier and its amplitude was higher in the session with meals rich in PA than in that with meals rich in OA. In healthy young males, meals rich in PA decreased fat oxidation and disrupted biological rhythms, particularly the sleep architecture and core body temperature during sleep, more than meals rich in OA.

Associations of objectively measured sedentary behavior and physical activity with cognitive function among older Japanese adults: An isotemporal substitution model / 体力科学

Increasing light-intensity physical activity (LPA) or moderate-to-vigorous physical activity (MVPA) and decreasing sedentary behavior (SB) are important to maintain cognitive function in older adults. However, there is a lack of studies examining the influence of replacing time spent in SB, LPA and MVPA on cognitive function. Therefore, this study applied an isotemporal substitution (IS) model approach to examine the associations of objectively measured SB, LPA, and MVPA on multiple cognitive functions in older adults. We analyzed data from 145 older persons (mean age, 75.1 ± 4.5 years; 61.4% women) in Kasama City, Japan. We assessed SB, LPA, and MVPA for seven consecutive days with a triaxial accelerometer. To evaluate the cognitive function, we used the Five-Cog test (character position referencing task, category cued recall task, clock drawing task, animal name listing task, and analogy task). The IS model of the multiple regression analysis was used to examine the effects of replacing time spent on one activity type with 30 minutes per day of SB, LPA, and MVPA on multiple cognitive functions, adjusting for age, gender, body mass index, education, smoking, sleep duration, history of stroke, medication for hypertension, dyslipidemia, and diabetes and accelerometer wear time. The results showed that reallocation from SB to LPA was significantly related to the category cued recall task score (B = 0.69, 95% confidence interval 0.07 - 1.31). In contrast, other reallocations were not associated with any cognitive tasks. The results suggest that substituting SB with LPA is positively associated with verbal episode memory among older Japanese adults.

Association between the timing of habitual physical activity and sleep in older adults / 体力科学

<p>We examined the relationship between the timing of habitual physical activities and sleep quality in older adults. The subjects were Japanese community-dwelling older adults (n=49, average age 70.1±3.5 years; men: 36.7%). We measured habitual physical activity using a 3-axis accelerometer (HJA-350 IT, Omron) for a week. Timing of physical activity was classified into the following three periods: (1) morning: waking to 11:59, (2) afternoon: 12:00 to 17:59, and (3) night: 18:00 to bedtime. We also categorized the intensity of habitual physical activity during 2 sessions as either (1) low (1.6-2.9 METs) or (2) moderate-to-vigorous (≧3.0 METs) intensity. The subjective sleep parameters were assessed using the Pittsburgh Sleep Quality Index (PSQI). We used a forced-entry multiple regression analysis to investigate the relationships between subjective sleep parameters and the timing of physical activities. Forced-entry multiple regression analysis revealed that sleep latency and PSQI global score were positively correlated with low-intensity physical activity at night. However, there was no significant correlation with moderate-to-vigorous activity. These results suggest that low-intensity habitual physical activity at night would be one useful and modifiable factor to improve sleep quality in the elderly.</p>