Validation of sleep-staging accuracy for an in-home sleep electroencephalography device compared with simultaneous polysomnography in patients with obstructive sleep apnea.

Efforts to simplify standard polysomnography (PSG) in laboratories, especially for obstructive sleep apnea (OSA), and assess its agreement with portable electroencephalogram (EEG) devices are limited. We aimed to evaluate the agreement between a portable EEG device and type I PSG in patients with OSA and examine the EEG-based arousal index's ability to estimate apnea severity. We enrolled 77 Japanese patients with OSA who underwent simultaneous type I PSG and portable EEG monitoring. Combining pulse rate, oxygen saturation (SpO2), and EEG improved sleep staging accuracy. Bland-Altman plots, paired t-tests, and receiver operating characteristics curves were used to assess agreement and screening accuracy. Significant small biases were observed for total sleep time, sleep latency, awakening after falling asleep, sleep efficiency, N1, N2, and N3 rates, arousal index, and apnea indexes. All variables showed > 95% agreement in the Bland-Altman analysis, with interclass correlation coefficients of 0.761-0.982, indicating high inter-instrument validity. The EEG-based arousal index demonstrated sufficient power for screening AHI ≥ 15 and ≥ 30 and yielded promising results in predicting apnea severity. Portable EEG device showed strong agreement with type I PSG in patients with OSA. These suggest that patients with OSA may assess their condition at home.

Relationship between rest-activity rhythms and cardiorespiratory fitness in middle-aged workers: a cross-sectional study with non-parametric analysis using accelerometers worn on the thigh.

BACKGROUND: Rest-activity rhythms are directly related to health risks, but there are limited objective methods to assess them. This study aimed to investigate the relationship between rest-activity rhythms and cardiorespiratory fitness (CRF) in middle-aged workers. METHODS: Peak oxygen uptake was measured on a treadmill to assess CRF in 254 middle-aged workers who were divided into low, medium, and high-CRF groups based on tertiles. Participants were asked to wear an accelerometer (activPAL) on their thighs for 1 week, and the logarithmically transformed acceleration data were used for the analysis of a 24-hour rest-activity rhythm. Sex, age, body mass index, occupation, smoking status, and alcohol consumption were used as covariates in Model 1, with Model 2 also including walking count on non-workdays. Repeated measures analysis of variance was used to compare time course of rest-activity rhythms changes on workdays between groups, and post-hoc tests were conducted using Bonferroni's correlation. RESULTS: Higher CRF correlated with increased physical activity. In model 1, higher CRF showed improved interdaily stability, but the significant difference disappeared in model 2 after adjusting for non-workday walking counts. A time-course group comparison showed that the high group had significantly higher activity levels than those of the low group from 6:00 to 8:59 and 17:00 to 17:59 and the medium group from 6:00 to 7:59 and 19:00 to 19:59. CONCLUSIONS: Workers who have better rest-activity rhythms and engage in higher levels of physical activity on workdays tend to have higher CRF levels. Regular daily routines, influenced by physical activity during holidays, can positively impact cardiopulmonary endurance.

Association between electroencephalogram-based sleep characteristics and physical health in the general adult population.

We examined the associations between electroencephalogram (EEG)-based sleep characteristics and physical health parameters in general adults via a cross-sectional study recruiting 100 volunteers aged 30-59 years. Sleep characteristics were measured at home using a portable multichannel electroencephalography recorder. Using the k-means + + clustering method, according to 10 EEG-based parameters, participants were grouped into better (n = 39), middle (n = 46), and worse (n = 15) sleep groups. Comparing 50 physical health parameters among the groups, we identified four signals of difference (P < 0.05), including systolic (sBP) and diastolic blood pressure (dBP), γ-glutamyl transpeptidase (γ-GTP), and serum creatinine, where sBP reached a Bonferroni-corrected threshold (P < 0.001). The sBP was higher by 7.9 (95% confidence interval 1.9-13.9) and 15.7 (7.3-24.0) mmHg before adjustment and 5.4 (- 0.1-10.9) and 8.7 (1.1-16.3) mmHg after adjustment for age, sex, body mass index, smoking, drinking habits, and 3% oxygen desaturation index in the middle and worse sleep groups, respectively, than in the better group. As another approach, among 500 combinations of EEG-based and physical health parameters, there were 45 signals of correlation, of which 4 (N1% and sBP, dBP, γ-GTP, and triglycerides) reached a Bonferroni-corrected threshold (P < 0.0001). Thus, EEG-based sleep characteristics are associated with several physical health parameters, particularly sBP.

Energy metabolism and thermoregulation during sleep in young and old females.

Core body temperature (CBT) shows a diurnal rhythm, and the nocturnal decrease in CBT is blunted in older people. The physiological mechanisms responsible for the blunted nocturnal decrease in CBT in older people remain to be revealed. The aim of this study was to compare heat production and heat dissipation in young and old subjects during sleep, as assessed by indirect calorimetry and the distal-proximal temperature gradient (DPG) of skin temperature. A complete dataset of 9 young (23.3 ± 1.1 years) and 8 old (72.1 ± 2.5 years) females was analyzed. CBT and energy metabolism were monitored during sleep using an ingestible temperature sensor in a metabolic chamber maintained at 25 °C. Skin temperature was measured at proximal and distal parts of the body. CBT, distal skin temperature, and DPG in older subjects were higher than in young subjects. Protein oxidation was similar between the two groups, but fat oxidation was lower and carbohydrate oxidation was higher in old subjects compared to young subjects. On the other hand, energy expenditure was similar between the two age groups. Thus, the elevated CBT in older subjects was not attributed to deteriorated heat dissipation or enhanced heat production, suggesting an alternative explanation such as deteriorated evaporative heat loss in old subjects.

Effects of home-based manual dexterity training on cognitive function among older adults: a randomized controlled trial.

BACKGROUND: The relationship between manual dexterity and cognitive function among older adults is well known; however, few studies have focused on manual dexterity training that confirms cognitive load of training in older adults through functional near-infrared spectroscopy (fNIRS) and verifies the effect of training. This study examined the effects of home-based manual dexterity training on cognitive function in older adults using a digital trail-making peg test device combining two conventional assessment tools namely, the peg and trail-making tests. METHODS: For 12 weeks, 57 healthy older adults aged 65-88 years participated in a parallel-group, randomized controlled trial, wherein home-based manual dexterity training was performed for approximately 20 min daily. To quantify the cognitive load in different manual dexterity conditions, we assessed the cortical activation patterns of the prefrontal cortex via a wearable four-channel fNIRS device. Participants in the control group were asked to continue their usual daily routines during the intervention period. Cognitive function was assessed using the Stroop Color and Word and Cognitive Impairment Tests. Manual dexterity was assessed using the Purdue Pegboard Test. All outcomes were estimated before and after the intervention. RESULTS: We observed significant differences in prefrontal cortical activation between the different manual dexterity conditions. Only the intervention group showed a significant improvement in Stroop interference (169.0-108.9 ms, p = 0.032) and an executive function and assembly task of the Purdue Pegboard Test (22.5-26.4 counts, p < 0.001). Additionally, except the clock drawing task, cognitive function had a larger effect size (Cohen's d) in the intervention group (d = 0.26-0.45) than in the control group (d = 0.11-0.28). CONCLUSIONS: Home-based manual dexterity training can improve performance in a complex manual dexterity task and executive functioning in older adults. TRIAL REGISTRATION: UMIN-CTR Clinical Trial, UMIN000047203. Registered 17 March 2022 - Retrospectively registered, https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr.cgi?function=brows&action=brows&recptno=R000053844&type=summary&language=E.

Exercise Timing Matters for Glycogen Metabolism and Accumulated Fat Oxidation over 24 h.

Due to increasingly diverse lifestyles, exercise timings vary between individuals: before breakfast, in the afternoon, or in the evening. The endocrine and autonomic nervous systems, which are associated with metabolic responses to exercise, show diurnal variations. Moreover, physiological responses to exercise differ depending on the timing of the exercise. The postabsorptive state is associated with greater fat oxidation during exercise compared to the postprandial state. The increase in energy expenditure persists during the post-exercise period, known as "Excess Post-exercise Oxygen Consumption". A 24 h evaluation of accumulated energy expenditure and substrate oxidation is required to discuss the role of exercise in weight control. Using a whole-room indirect calorimeter, researchers revealed that exercise performed during the postabsorptive state, but not during the postprandial state, increased accumulated fat oxidation over 24 h. The time course of the carbohydrate pool, as estimated by indirect calorimetry, suggests that glycogen depletion after postabsorptive exercise underlies an increase in accumulated fat oxidation over 24 h. Subsequent studies using 13C magnetic resonance spectroscopy confirmed that the variations in muscle and liver glycogen caused by postabsorptive or postprandial exercise were consistent with indirect calorimetry data. These findings suggest that postabsorptive exercise alone effectively increases 24 h fat oxidation.

Instability of non-REM sleep in older women evaluated by sleep-stage transition and envelope analyses.

Study objective: Traditionally, age-related deterioration of sleep architecture in older individuals has been evaluated by visual scoring of polysomnographic (PSG) recordings with regard to total sleep time and latencies. In the present study, we additionally compared the non-REM sleep (NREM) stage and delta, theta, alpha, and sigma wave stability between young and older subjects to extract features that may explain age-related changes in sleep. Methods: Polysomnographic recordings were performed in 11 healthy older (72.6 ± 2.4 years) and 9 healthy young (23.3 ± 1.1 years) females. In addition to total sleep time, the sleep stage, delta power amplitude, and delta, theta, alpha, and sigma wave stability were evaluated by sleep stage transition analysis and a novel computational method based on a coefficient of variation of the envelope (CVE) analysis, respectively. Results: In older subjects, total sleep time and slow-wave sleep (SWS) time were shorter whereas wake after sleep onset was longer. The number of SWS episodes was similar between age groups, however, sleep stage transition analysis revealed that SWS was less stable in older individuals. NREM sleep stages in descending order of delta power were: SWS, N2, and N1, and delta power during NREM sleep in older subjects was lower than in young subjects. The CVE of the delta-band is an index of delta wave stability and showed significant differences between age groups. When separately analyzed for each NREM stage, different CVE clusters in NREM were clearly observed between young and older subjects. A lower delta CVE and amplitude were also observed in older subjects compared with young subjects in N2 and SWS. Additionally, lower CVE values in the theta, alpha and sigma bands were also characteristic of older participants. Conclusion: The present study shows a decrease of SWS stability in older subjects together with a decrease in delta wave amplitude. Interestingly, the decrease in SWS stability coincided with an increase in short-term delta, theta, sigma, and alpha power stability revealed by lower CVE. Loss of electroencephalograms (EEG) variability might be a useful marker of brain age.

Bidirectional associations between physical activity and sleep in older adults: a multilevel analysis using polysomnography.

Although recent studies have examined the bidirectional associations between physical activity and sleep parameters, few have focused on older adults utilizing objective assessments, such as polysomnography. This micro-longitudinal observational study included 92 Japanese older adults (aged 65-86 years) who underwent objective evaluations of sleep quality using polysomnography and completed subjective sleep-related questionnaires. Activity levels were assessed using an accelerometer. Polysomnography, subjective sleep-related questionnaires, and accelerometer were administered for 7 consecutive days. Multilevel models (participant-, day-level) were used to examine the temporal associations of objective and subjective sleep parameters with sedentary behavior and physical activity. In the day-level analysis, higher levels of sedentary behavior during daytime were associated with longer rapid eye movement (REM) sleep, shorter REM latency, lower levels of non-REM sleep (stage N3), and reduced delta power during daytime. Higher levels of low-intensity physical activity during daytime were associated with lower levels of REM sleep, longer REM latency, and increased stage N3 sleep in the day-level analysis. Higher levels of moderate-to-vigorous physical activity were associated with increased REM latency. Longer subjective sleep time was associated with increased next-day moderate-to-vigorous physical activity. Thus, low-intensity physical activity may provide objective benefits related to deep sleep parameters in older adults.

[Relationship between performance on the Digital Trail Making Peg test and cognitive function in older adults].

AIM: To determine the relationship between performance on the Digital Trail Making Peg test (DTMP) and cognitive function in older adults. METHODS: A total of 203 community-dwelling older adults (mean age: 76.4±5.1 years old) participated in this study. The five-cog test was used to assess the cognitive function. The DTMP measured completion time, number of errors and intra-individual variability for performance variability (coefficient of variation, CV; inter-elemental variability, IEV). Spearman's rank correlation coefficient (ρ) was calculated to examine the association between each variable. In addition, a multiple regression analysis was performed with the cognitive function score as the dependent variable and the DTMP completion time, number of errors, CV, and IEV as the independent variables, with adjusting for the sex, age, years of education, body mass index, medical history, depression, and physical function. RESULTS: The rank correlation coefficients with cognitive function scores were as follows: completion time, ρ = -0.479 (P < 0.01), number of errors, ρ = -0.068 (P = 0.332), CV, ρ = 0.085 (P = 0.225), IEV, ρ = -0.316 (P < 0.01). The results of the multiple regression analysis showed that completion time (ß = -0.566), CV (ß = 0.164), IEV (ß = 2.736) were significantly associated with cognitive function scores. CONCLUSIONS: The shorter the DTMP completion time, the better the overall cognitive function. However, the intra-individual variability of CV and IEV did not show consistent results, with smaller values indicating less intra-individual variability.

Effect of 12-Week Intake of Nicotinamide Mononucleotide on Sleep Quality, Fatigue, and Physical Performance in Older Japanese Adults: A Randomized, Double-Blind Placebo-Controlled Study.

Deteriorating sleep quality and physical or mental fatigue in older adults leads to decreased quality of life and increased mortality rates. This study investigated the effects of the time-dependent intake of nicotinamide mononucleotide (NMN) on sleep quality, fatigue, and physical performance in older adults. This randomized, double-blind placebo-controlled study evaluated 108 participants divided into four groups (NMN_AM; antemeridian, NMN_PM; post meridian, Placebo_AM, Placebo_PM). NMN (250 mg) or placebo was administered once a day for 12 weeks. Sleep quality was evaluated using the Pittsburgh Sleep Quality Index. Fatigue was evaluated using the "Jikaku-sho shirabe" questionnaire. Grip strength, 5-times sit-to-stand (5-STS), timed up and go, and 5-m habitual walk were evaluated to assess the physical performance. Significant interactions were observed between 5-STS and drowsiness. 5-STS of all groups on post-intervention and drowsiness of the NMN_PM and Placebo_PM groups on mid- and post-intervention showed significant improvement compared with those in pre-intervention. The NMN_PM group demonstrated the largest effect size for 5-STS (d = 0.72) and drowsiness (d = 0.64). Overall, NMN intake in the afternoon effectively improved lower limb function and reduced drowsiness in older adults. These findings suggest the potential of NMN in preventing loss of physical performance and improving fatigue in older adults.

Pre-frailty associated with traffic crashes in Japanese community-dwelling older drivers.

Objectives: Frailty might be useful to identify older drivers who are at risk for traffic crashes. We aim to examine the association between pre-frailty/frailty defined by the Kihon Checklist (KCL) and the involvement of traffic crashes and clarify whether some domains of the KCL are associated with traffic crashes.Methods: This cross-sectional study analyzed data from 2,208 Japanese community-dwelling older drivers aged ≥ 65 years in Kasama City, who participated in our postal survey in November 2019. A self-reported history of traffic crashes was used to divide participants into non-crash-involved and crash-involved groups.Results: A total of 192 (8.7%) participants had been involved in traffic crashes in the past year. The crash-involved group was found to have gained more body mass index, driven more frequently, and scored higher on the total KCL score than the non-crash-involved group (all P < .05). Binary logistic regression analyses showed that after adjusting for age, sex, education, driving frequency, and driving distance, pre-frailty (OR = 1.52, 95% CI: 1.10-2.10) was more significantly associated with traffic crashes as compared to robustness. Those who had impairment in the oral domain (OR = 1.57, 95% CI: 1.09-2.27) and memory domain (OR = 1.38, 95% CI: 1.01-1.90) were also more likely to be involved in traffic crashes.Conclusion: The results suggest that identifying pre-frailty may play an important pole in crash prevention. Additionally, more attention should be given to older drivers with oral dysfunction and cognitive impairment.

Combined effect of daily physical activity and social relationships on sleep disorder among older adults: cross-sectional and longitudinal study based on data from the Kasama study.

BACKGROUND: This study investigated whether daily physical activity of older adults, combined with social relationships, is associated with the risk of sleep disorder. Further, it determined whether a high level of one variable with a low level of the other, leads to a significantly lower risk of sleep disorder than low levels of both. METHODS: The sample comprised 1339 community-dwelling older Japanese adults: 988 in Study 1 and 351 in Study 2. The level of daily physical activity and range of social relationships were assessed using the Physical Activity Scale for the Elderly and the Lubben Social Network Scale, respectively. The Pittsburgh Sleep Quality Index was used to assess sleep disorder. To test the combined relationships and effects in Studies 1 and 2, the medians for the respective scores of each of the following four groups that the participants were categorized into, were calculated: (1) low activity group with low social relationships, (2) low activity group with high social relationships, (3) high activity group with low social relationships, and (4) high activity group with high social relationships. After adjusting for potential confounders, a logistic regression analysis was conducted in Study 1. After adjusting for potential confounders, a Cox proportional hazards regression analysis was conducted in Study 2. RESULTS: Study 1 revealed that the high activity group with high social relationships showed a significantly lower risk of sleep disorder (ORs: 0.585, 95% CI: 0.404-0.847) than the low activity group with low social relationships. Study 2 also revealed that the high activity group with high social relationships showed a significantly lower prevalence of sleep disorder (HRs: 0.564, 95% CI: 0.327-0.974) than the low activity group with low social relationships. CONCLUSIONS: Our findings suggest that for older adults with high social relationships, being physically active is favorably associated with sleep quality. However, a high level of one variable with a low level of the other has not been confirmed in improving sleep quality among older adults.

Effect of a single bout of morning or afternoon exercise on glucose fluctuation in young healthy men.

The timing of exercise plays an important role in the effect of the exercise on physiological functions, such as substrate oxidation and circadian rhythm. Exercise exerts different effects on the glycemic response to exercise and meal intake depending on when the exercise performed. Here, we comprehensively investigated the effects of the timing (morning or afternoon) of exercise on glucose fluctuation on the basis of several indices: glycemic variability over 24 h (24-h SD), J-index, mean amplitude of glucose excursions (MAGE), continuous overall net glycemic action (CONGA), and detrended fluctuation analysis (DFA). Eleven young men participated in 3 trials in a repeated measures design in which they performed a single bout of exercise at 60% of their maximal oxygen uptake for 1 h beginning either at 7:00 (morning exercise), 16:00 (afternoon exercise), or no exercise (control). Glucose levels were measured using a continuous glucose monitoring system (CGMs). Glucose fluctuation was slightly less stable when exercise was performed in the afternoon than in the morning, indicated by higher CONGA at 2 h and α2 in DFA in the afternoon exercise trial than in the control trial. Additionally, decreased stability in glucose fluctuation in the afternoon exercise trial was supported by the descending values of the other glucose fluctuation indices in order from the afternoon exercise, morning exercise, and control trials. Meal tolerance following exercise was decreased after both exercise trials. Glucose levels during exercise were decreased only in the afternoon exercise trial, resulting in less stable glucose fluctuations over 24 h.

Associations between exercising in a group and physical and cognitive functions in community-dwelling older adults: a cross-sectional study using data from the Kasama Study.

[Purpose] To examine the associations of exercise habits, particularly exercising in a group, with physical and cognitive functions in community-dwelling older adults. [Participants and Methods] A total of 615 older adults participated in this cross-sectional study. We conducted three physical performance tests (grip strength, five times sit-to-stand, and 5-meter walk tests) and the Five-Cog test (attention, memory, visuospatial, language, and reasoning). We investigated exercise habits using questionnaires and classified the participants into three groups as follows: those who did not exercise (n=86), those who exercised alone (n=168), and those who exercised in a group (n=362). To clarify the associations of exercise habits with physical and cognitive functions, we used the analysis of covariance with adjustment for potential confounders. [Results] The participants who exercised in a group had better lower limb strength than those who exercised alone and better scores for all the variables than the non-exercisers. Furthermore, those who exercised in a group scored significantly higher on the attention, memory, visuospatial, and overall cognitive function tests than those who exercised alone. [Conclusion] Our results highlight the importance of the social aspects associated with exercising, such as the presence of exercise peers, to improve the physical and cognitive health of older adults.

Effects of Morning Versus Evening Home-Based Exercise on Subjective and Objective Sleep Parameters in Older Adults: A Randomized Controlled Trial.

OBJECTIVE: This study aimed to determine whether the timing of exercise influenced the effects of home-based low-intensity stepping exercises on the sleep parameters of older adults. METHOD: For 8 weeks, 60 healthy older adults participated in a randomized controlled trial, performing low-intensity aerobic exercise (70-80 bpm) for about 30 minutes every day at home, either in the morning (from waking until 12:00) or evening (18:00 to bedtime). RESULTS: In the evening exercise group, both subjectively and objectively measured sleep latency significantly improved throughout the intervention. Further, postintervention subjective sleep satisfaction was significantly higher in the evening group (6.2 ± 1.3 points) than in the morning group (5.2 ± 1.4 points; P = .006). Additionally, sleep variables related to evening exercise had larger effect sizes (Cohen d) than those performed in the morning. CONCLUSION: Engaging in low-intensity stepping exercises during the evening is potentially a useful nonpharmacological approach to improving sleep quality among older adults.

Distinct effects of low-intensity physical activity in the evening on sleep quality in older women: A comparison of exercise and housework.

BACKGROUND: The effects of intensity, type, and time of day of physical activity on sleep are not well understood. An appropriate increase in core body temperature, due to physical activity during daytime, aids sleep in older adults. Our previous study showed that evening exercise has more positive effects on sleep quality in older adults when compared with morning exercise. However, older adults who do not exercise form a large part of the population. This study aimed to examine the distinct effects of low-intensity exercise and housework during the evening on sleep quality in older women. METHODS: This randomized crossover study included 10 healthy older women aged 65-79 years. The participants engaged in low-intensity physical activity for 30 min, either aerobic exercise (70 steps per minute), housework (at the same intensity), or remained sedentary (control) 3 h before bedtime. Sleep was recorded polysomnographically, and self-reported sleep quality was assessed the next morning using the Oguri-Shirakawa-Azumi sleep inventory, Middle-Aged and Aged version (OSA-MA) questionnaire. RESULTS: Compared with the control trial, core body temperature was significantly elevated in participants after each activity trial (0.5 ± 0.4 and 0.4 ± 0.4 °C for housework and aerobic exercise, respectively). There was a significant difference in sleep latency (14.2 ± 19.1, 9.9 ± 15.6, and 4.2 ± 3.5 min for control, housework, and aerobic exercise, respectively; ANOVA P = 0.011) among the trials. The delta power density after aerobic exercise was significantly higher than that after the control trial. We observed an increase of 53% and 15% in delta power during the 1st hour of sleep as a result of aerobic exercise and housework, respectively. The total score on OSA-MA was significantly higher after aerobic exercise (91.0 ± 5.4, 88.1 ± 6.9, and 108.6 ± 5.9 points for control, housework, and exercise, respectively). CONCLUSIONS: Engaging in low-intensity aerobic exercise in the evening improved polysomnographic and self-reported sleep quality. Although housework increased core body temperature to the same level as that observed after aerobic exercise, self-reported sleep quality after housework was lower than that after aerobic exercise.

Subacute Ingestion of Caffeine and Oolong Tea Increases Fat Oxidation without Affecting Energy Expenditure and Sleep Architecture: A Randomized, Placebo-Controlled, Double-Blinded Cross-Over Trial.

Ingesting oolong tea or caffeine acutely increases energy expenditure, and oolong tea, but not caffeine, stimulates fat oxidation. The acute effects of caffeine, such as increased heart rate and interference with sleep, diminish over 1-4 days, known as caffeine tolerance. During each 14-day session of the present study, 12 non-obese males consumed oolong tea (100 mg caffeine, 21.4 mg gallic acid, 97 mg catechins and 125 mg polymerized polyphenol), caffeine (100 mg), or placebo at breakfast and lunch. On day 14 of each session, 24-h indirect calorimetry and polysomnographic sleep recording were performed. Caffeine and oolong tea increased fat oxidation by ~20% without affecting energy expenditure over 24-h. The decrease in the respiratory quotient by oolong tea was greater than that by caffeine during sleep. The effect of oolong tea on fat oxidation was salient in the post-absorptive state. These findings suggest a role of unidentified ingredients in oolong tea to stimulate fat oxidation, and this effect is partially suppressed in a postprandial state. Two weeks of caffeine or oolong tea ingestion increased fat oxidation without interfering with sleep. The effects of subacute ingestion of caffeine and oolong tea differed from the acute effects, which is a particularly important consideration regarding habitual tea consumption.

Effect of Exercising with Others on Incident Functional Disability and All-Cause Mortality in Community-Dwelling Older Adults: A Five-Year Follow-Up Survey.

We clarified the effect of exercising with others on the risks of incident functional disability and all-cause mortality among community-dwelling adults. We used an inventory mail survey with a five-year follow-up for 1520 independently living older adults (mean age: 73.4 ± 6.3 years) in Kasama City, Japan. Subjects responded to a self-reported questionnaire in June 2014. Exercise habits and the presence of exercise partners were assessed. Subjects were classified into three groups: Non-exercise, exercising alone, and exercising with others. Follow-up information and date of incident functional disability and death during the five-year follow-up were collected from the database. To compare the association between exercise habits and functional disability and mortality, Cox regression analysis was conducted. Compared with the non-exercise group, exercising with others had significantly lower hazard ratios (HRs) for functional disability (0.59, 95% confidence interval (CI) 0.40-0.88) and mortality (0.40, 95% CI 0.24-0.66) in the covariate models. Compared with exercising alone, exercising with others decreased the HRs for incident functional disability (0.53, 95% CI: 0.36-0.80) and mortality (0.50, 95% CI 0.29-0.85) rates in the unadjusted model; these associations were not significant in the covariate models. Exercising with others can contribute to functional disability prevention and longevity.

Changes in sleeping energy metabolism and thermoregulation during menstrual cycle.

Women with ovulatory menstrual cycles show an increase in body temperature in the luteal phase, compared with follicular phase, particularly during the night. Several, albeit not all, studies reported higher energy expenditure in the luteal phase compared with follicular phase. Q10 of biological reactions lies between 2.0 and 3.0, predicting a 7-12% increase in energy expenditure when body temperature rises by 1°C. In this study, temperature dependence of energy expenditure was assessed by comparing changes in sleeping energy expenditure and thermoregulation with menstrual cycle in 9 young females. Energy expenditure was measured using a metabolic chamber, in which sleep was recorded polysomnographically, and core body temperature and skin temperature were continuously monitored. Distal-to-proximal skin temperature gradient was assessed as an index of heat dissipation. In the luteal phase, a significant increase in average core body temperature (+0.27°C) and energy expenditure (+6.9%) were observed. Heat dissipation was suppressed during the first 2 hr of sleep in the luteal phase, compared with follicular phase. Rise in basal body temperature in the luteal phase was accompanied by increased energy expenditure and suppressed heat dissipation. The 6.9% increase in metabolic rate would require a Q10 of 12.4 to be attributable solely to temperature (+0.27°C), suggesting that energy expenditure in the luteal phase is enhanced through the mechanism, dependent and independent of luteal-phase rise in body temperature presumably reflects other effects of the sex hormones.

Effects of sedentary behavior and physical activity on sleep quality in older people: A cross-sectional study.

The aim of this cross-sectional study was to investigate the influence of replacing sedentary time with time engaged in one of two levels of physical activity on sleep quality using an isotemporal substitution model. The participants were 70 community-dwelling older Japanese adults (approximately 70% female). Physical activity types were measured using a triaxial accelerometer and categorized based on intensity as sedentary, light-intensity, and vigorous-intensity. The Pittsburgh Sleep Quality Index assessed subjective sleep quality. Objective sleep parameters were assessed using an actigraph. A series of multi-linear regression models analyzed the statistical relationships. Our findings showed that replacing 30 min of sedentary activity per day with an equal period of light-intensity physical activity significantly influenced sleep quality parameters. However, there was no significant difference in sleep quality when light-intensity activity was replaced with vigorous-intensity activity. Engaging in one activity type means less available time for other types of activity; habitual replacement of sedentary activity with light-intensity physical activity might have long-term benefits on the sleep quality of older people.