Associations between objectively measured overall and intensity-specific physical activity and phase angle in older adults.

Phase angle (PhA) is an indicator of cellular health and is positively associated with overall physical activity (PA). However, varied associations between different intensities of PA and PhA by body segment in older populations remain unexplored. We investigated the associations between overall and different intensities of PA and upper-, lower-, and whole-body PhA in older adults. Overall exposure to light-intensity (LPA), moderate-intensity (MPA), and vigorous-intensity physical activity (VPA) was assessed using a triaxial accelerometer (GT3X + , ActiGraph). The outcome variables were upper-, lower-, and whole-body PhA measured using bioelectrical impedance analysis (MC-780MA, TANITA). Multiple linear regression helped examine the associations between the exposure and outcome variables after adjusting for age, gender, body mass index, and accelerometer wear time. A cross-sectional analysis involved 166 community-dwelling older participants (mean age = 72.1 ± 5.5 years; 78.3% women). Overall PA was associated with larger upper- (B: 0.057, 95% confidence interval [CI] 0.018-0.095) and whole-body PhA (B: 0.044, 95% CI 0.006-0.081). LPA was associated with larger upper-body PhA (B: 0.059, 95% CI 0.017-0.101), and MPA was associated with larger lower- (B: 0.273, 95% CI 0.128-0.419) and whole-body PhA (B: 0.141, 95% CI 0.002-0.280). VPA and PhA were not associated. Future interventions targeting PhA in older adults should consider the differential impact of PA intensity on various body segments of the PhA.

Associations of accelerometer-measured sedentary behavior and physical activity with sleep in older adults.

BACKGROUND: Few studies have examined the non-linear relationships of objectively-measured sedentary behavior and physical activity with insomnia symptoms in older adults. We investigated such relationships of sedentary and physically-active behaviors with total sleep time and nocturnal wakefulness. METHODS: We recruited adults aged 60 years and above who have received health check-ups or been to geriatric outpatient services from a hospital setting. Sedentary and physically-active behaviors, total sleep time, and wakefulness time after sleep onset were measured by Actigraphy, and their relationships were estimated using generalized additive models. RESULTS: The 157 older adults receiving health-related services slept 7.5 h (20.8 min awake) on average per day. Total sleep time was negatively associated with sedentary and physically-active behaviors. By contrast, a U-shape relationship was found between sedentary behavior and wakefulness time after sleep onset, with a turning point at a daily sedentary time of 10.9 h. CONCLUSION: Longer high-intensity physical activity time was related to a shorter wakefulness time after sleep onset. By contrast, daily sedentary time longer than 10.9 h was related to shorter total sleep time but more nocturnal wakefulness time. Future nonpharmacological strategies for sleep improvement should consider the sedentary threshold.

Objective assessment of the association between frailty and sedentary behavior in older adults: a cross-sectional study.

BACKGROUND: Given the inconsistent findings of the association between frailty and sedentary behavior in older adults, this cross-sectional study investigated the aforementioned association using four different frailty criteria and two sedentary behavior indices in older adults. METHODS: Data from older adults (age ≥ 65 y) who participated in health examinations or attended outpatient integrated clinics at a medical center in Taipei, Taiwan, were collected. Frailty was measured using the modified Fried Frailty Phenotype (mFFP), Clinical Frailty Scale in Chinese Translation (CFS-C), Study of Osteoporotic Fractures (SOF) index, and Clinical Frailty-Deficit Count (CF-DC) index; sedentary behavior was assessed with a waist-worn accelerometer. Adjusted linear regression ascertained the association between frailty and both sedentary behavior outcomes. RESULTS: Among the 214 participants (mean age 80.82 ± 7.14 y), 116 were women. The average total sedentary time and number of sedentary bouts were 609.74 ± 79.29 min and 5.51 ± 2.09 times per day, respectively. Frail participants had a longer total sedentary time (odds ratio [OR]: 30.13, P = .01 and 39.43, P < .001) and more sedentary bouts (OR: 3.50 and 5.86, both P < .001) on mFFP and CFS-C assessments, respectively. The SOF index revealed more sedentary bouts among frail than in robust participants (OR: 2.06, P = .009), without a significant difference in the total sedentary time. Frail participants defined by the CF-DC index were more likely to have frequent sedentary bouts (OR: 2.03, P = .016), but did not have a longer total sedentary time. CONCLUSIONS: Regardless of the frailty criteria adopted, frailty was positively associated with the number of sedentary bouts per day in older adults. A significant correlation between frailty and total sedentary time was detected only with mFFP and CFS-C indices. Further research may target decreasing the sedentary bouts in older adults as a strategy to improve frailty.

The Association between a Minimum Amount of Physical Activity and Subsequent Muscle Strength and Balance in Older Adults: A Prospective Study.

This study aimed to investigate the association between 15 min of daily moderate-to-vigorous physical activity (MVPA) and subsequent muscle strength and balance in older adults. Data concerning community-dwelling older Taiwanese adults (mean age, 69.5 years) were collected during the baseline period (2018) and at a 12-month follow-up survey (2019). Time spent performing MVPA was objectively assessed using a triaxial accelerometer (ActiGraph wGT3x-BT) at baseline. Upper and lower limb muscle strength were measured using handgrip strength and a five-times sit-to-stand test, respectively. Balance was assessed using a one-leg standing test. The 12-month variations in muscle strength and balance were calculated through subtracting follow-up data from baseline data. A forced entry-adjusted logistic regression analysis was conducted. In total, 65.2% of participants engaged in at least 15 min of daily MVPA in the baseline survey. After adjusting for confounders, older adults who achieved 15 min of daily MVPA during the baseline period were more likely to maintain or improve balance performance (odds ratio, 8.12). Performing 15 min of daily MVPA was found to benefit older adults' subsequent balance performance but not muscle strength.

Diurnal pattern of breaks in sedentary time and the physical function of older adults.

BACKGROUND: The association of breaks in sedentary time with outcomes of physical function can vary according to the time of day. We examined the association of the diurnal pattern of breaks in sedentary time with physical function outcomes in older adults. METHODS: A cross-sectional analysis was conducted among 115 older adults (≥60 years). The overall and time-specific breaks (morning: 06:00-12:00; afternoon: 12:00-18:00; evening: 18:00-24:00) in sedentary time were assessed using a triaxial accelerometer (Actigraph GT3X+). A break in sedentary time was defined as at least 1 min where the accelerometer registered ≥100 cpm following a sedentary period. Five physical function outcomes were assessed: handgrip strength (dynamometer), balance ability (single leg stance), gait speed (11-m walking), basic functional mobility (time up and go), and lower-limb strength (five times sit-to-stand). Generalized linear models were used to examine the associations of the overall and time-specific breaks in sedentary time with the physical function outcomes. RESULTS: Participants showed an average of 69.4 breaks in sedentary time during the day. Less frequent breaks in the evening (19.3) were found than that in the morning (24.3) and the afternoon (25.3) (p < 0.05). Breaks in sedentary time during the day were associated with less time on gait speed in older adults (exp (ß) = 0.92, 95% confidence interval [CI] 0.86-0.98; p < 0.01). Time-specific analysis showed that breaks in sedentary time were associated with less time on gait speed (exp (ß) = 0.94, 95% CI 0.91-0.97; p < 0.01), basic functional mobility (exp (ß) = 0.93, 95% CI 0.89-0.97; p < 0.01), and lower-limb strength (exp (ß) = 0.92, 95% CI 0.87-0.97; p < 0.01) in the evening only. CONCLUSION: A break in sedentary time, particularly during the evening, was associated with better lower extremity strength in older adults. Further strategies to interrupt sedentary time with frequent breaks, with an emphasis on evening hours, can be helpful to maintain and improve physical function in older adults.

Effect of isotemporal substitution of sedentary behavior with different intensities of physical activity on the muscle function of older adults in the context of a medical center.

BACKGROUND: Engaging in physical activity and reducing sedentary time in daily life may enable older individuals to maintain muscle mass. This study aimed to investigate the effects of replacing sedentary behavior with light physical activity (LPA) or moderate-to-vigorous physical activity (MVPA) on the muscle function of older adults at a medical center in Taiwan. METHODS: We recruited 141 older adults (51.1% men; 81.1 ± 6.9 years old) and asked them to wear a triaxial accelerometer on the waist to measure their sedentary behavior and physical activity. Functional performance was assessed based on handgrip strength, Timed Up and Go (TUG) test, gait speed, and five-times-sit-to-stand test (5XSST). Isotemporal substitution analysis was performed to examine the effect of substituting 60 min of sedentary time with 60 min of LPA, MVPA, and combined LPA and MVPA in different proportions. RESULTS: Reallocating 60 min of sedentary behavior per day to LPA was associated with better handgrip strength (Beta [B] = 1.587, 95% confidence interval [CI] = 0.706, 2.468), TUG test findings (B = -1.415, 95% CI = -2.186, -0.643), and gait speed (B = 0.042, 95% CI = 0.007, 0.078). Reallocating 60 min of sedentary behavior per day to MVPA was associated with better gait speed (B = 0.105, 95% CI = 0.018, 0.193) and 5XSST findings (B = -0.060, 95% CI = -0.117, -0.003). In addition, each 5-min increment in MVPA in the total physical activity replacing 60 min of sedentary behavior per day resulted in greater gait speed. Replacing 60 min of sedentary behavior with 30-min of LPA and 30-min of MVPA per day significantly decreased the 5XSST test time. CONCLUSION: Our study indicates that introducing LPA and a combination of LPA and MVPA to specifically replace sedentary behavior may help maintain muscle function in older adults.

Associations of the audited residential neighborhood built-environment attributes with objectively-measured sedentary time among adults: a systematic review.

This study systematically reviewed the relevant studies and summarized the associations of objective measures of residential neighborhood built-environment attributes with sedentary time among adults. Published studies were obtained from PubMed and Scopus, restricting to those published in English language peer-reviewed journals to Oct. 2021. There were nine studies and 48 instances of estimated associations. Most instances showed no statistical-significant associations; by contrast, few instances showed that adults living in a neighborhood characterized by a high density of local destinations and connected intersections were associated with less sedentary time. The findings suggest that a high density of destinations and street intersections around residence may provide opportunities to transfer and access to services, thus reducing the sedentary time. Future research strengthening the research design and measurements are needed to investigate the potential explanations of the associations between residential neighborhood built environments and sedentary time in adults.

Effects of Coordinative Exercise on Sustained Attention and Perceptual Discrimination in Elementary School Physical Education.

Purpose: This study examined the effects of coordinative exercise on children's sustained attention and perceptual discrimination in a school-based physical education (SBPE) setting. Methods: Seventy-three children received an intervention of moderate-to-vigorous intensity coordinative exercise, and 75 children participated in a moderate-to-vigorous intensity physical activity as part of a regular physical education class. Two neuropsychological tests of executive function (EF) were used to assess attention and perceptual discrimination functions before and after each treatment. Results: The results found that coordinative exercise significantly improved the performances on sustained attention and perceptual discrimination, as evidenced by enhanced response accuracy and improved speed of responding. Specifically, higher progressions in task performance were seen following coordinative exercise relative to regular physical activity. Conclusion: These findings suggest that coordinative exercise could enable more robust improvements in sustained attention and perceptual discrimination among children. Overall, we conclude that structured coordinative exercise, implemented in SBPE settings, may be a promising alternative to promote children's cognitive abilities.

Relationship of sleep regularity with device-based sedentary behavior time and physical activity time in working adults.

OBJECTIVES: This study aimed to investigate the association of sleep regularity with time spent in sedentary behavior (SB) and physical activity (PA) in adults with full-time jobs. METHODS: This was a cross-sectional study. Adults aged 21-64 years with full-time jobs were recruited between August 2019 and December 2020 in Taiwan. The time spent in SB/PA was assessed using triaxial accelerometers (Actigraph wGT3x-BT), and PA was further classified into light-intensity physical activity (LPA) and moderate-to-vigorous intensity physical activity (MVPA). Each participant recorded their daily sleep patterns and work hours in a log, which was further used to measure sleep variability and social jet lag. Linear regression was applied to examine the associations of indicators of sleep regularity with SB time and PA time. RESULTS: A total of 192 adults (men = 28.13%; mean age = 38.56 ± 8.89 years) were included in this study. After adjusting for potential covariates, greater social jet lag was related to more SB time (unstandardized coefficient [B] = 14.39, P = .005) and less LPA time (B = -0.02, P = .010). No evidence of an association between other indicators of sleep regularity with SB/PA time was found. CONCLUSIONS: These results provide evidence for a relationship between sleep regularity and SB/PA time in working adults. Maintaining regular sleep, especially a small social jet lag, was suggested to promote physical activity and avoid a sedentary lifestyle. Future research is recommended to examine work-related influences on the associations and bidirectional relationship between sleep regularity and SB/PA.

Domain-specific Physical Activity and the Risk of All-cause Mortality Among Middle-aged and Older Adults in Taiwan: A Prospective Cohort Study.

BACKGROUND: The impact of meeting leisure-time physical activity (LTPA) recommendations and household physical activity (HPA) on all-cause mortality in the Taiwanese population is unclear. We aimed to investigate the relationship between sufficient LTPA and all-cause mortality in middle-aged and older Taiwanese adults and the role of HPA in those with insufficient LTPA. METHODS: This nationwide prospective cohort study included 4,960 participants aged ≥50 years from the Taiwan Longitudinal Study in Aging (TLSA) survey. Physical activity patterns were assessed in 2003 and then followed up until 2015 for mortality through the National Death Registration Record. Cox proportional hazards regression was conducted to evaluate hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause mortality. RESULTS: Of the 4,960 participants, 1,712 died of all-cause mortality. Compared to those who had insufficient LTPA, participants who engaged in sufficient LTPA showed a significantly lower risk of all-cause mortality (HR = 0.84, 95% CI, 0.73-0.97). For those with insufficient LTPA, HPA also had a significantly reduced risk of all-cause mortality (HR = 0.85, 95% CI, 0.75-0.96) among general population. Similar associations were observed in subsequent sensitivity analyses. The subgroup analysis showed that the relationship between HPA and reduced mortality risk was only found in the women with insufficient LTPA group. CONCLUSION: This study confirmed that sufficient LTPA is associated with a lower risk of all-cause mortality. If sufficient LTPA cannot be performed, additional HPA is related to lower mortality.

Substituting sedentary time with physical activity in youngest-old to oldest-old community-dwelling older adults: Associations with body composition.

Introduction: Several studies have suggested that physical activity and sedentary behavior are strongly and independently associated with body composition and obesity. However, few studies have investigated whether substituting sedentary time with moderate-to-vigorous physical activity is associated with body composition in older adults, especially among those older than 75 years. Methods: This study examined the associations between replacing sedentary time with physical activity and obesity indices in a sample of 199 community-dwelling older Taiwanese adults (52.3% women; 80.6 ± 7.0 years). Physical activity and sedentary behavior were measured using the triaxial accelerometer (GT3X+, ActiGraph). Body composition indices were computed through a bioelectrical impedance analysis of body fat percentage and appendicular skeletal muscle mass index. Waist circumference and body mass index were measured by trained personnel. Isotemporal substitution analyses estimated these associations after adjusting for sociodemographic characteristics and nutritional status. Results: The study showed that substituting 30 min of sedentary behavior per day with moderate-to-vigorous physical activity was associated with lower body fat percentage (B = -1.408, 95% CI = -2.55, -0.264), body mass index (B = -0.681, 95% CI = -1.300, -0.061), and waist circumference (B = -2.301, 95% CI = -4.062, -0.539) after adjusting for covariates. Substituting 30 min of light physical activity per day with moderate-to-vigorous physical activity was associated with lower waist circumference (B = -2.230, 95% CI = -4.173, -0.287) after adjusting for covariates. Stratified analyses indicated that associations were stronger in youngest-old older adults, and in older adults with a normal nutritional status (vs. underweight status). Discussion: These findings confirm the importance of reducing sedentary behavior and increasing moderate-to-vigorous physical activity among older adults to improve their physical health, as well as highlighting the importance of taking into account nutritional status and age group.

Nonlinear associations between sleep patterns and sarcopenia risks in older adults.

STUDY OBJECTIVES: Despite considering it as a common geriatric condition, sarcopenia is linked to various behavioral factors that may be changeable. As sleep is one of the important routines in physiological homeostasis, further investigating the underlying relationships of sleep behavior with sarcopenia is urgently needed. We examined the association between sleep parameters (ie, sleep duration, bedtime, wake time, or midsleep time) and sarcopenia risks in older adults, in the total sample and age group subsamples. METHODS: A total of 1,068 older adults in Taiwan were included. Data on bedtime, wake time, and sleep duration were collected through telephone interview. Midsleep time was calculated by the midpoint of bedtime and wake time. Sarcopenia was screened by the SARC-F questionnaire composed of 5 questions (the strength, assistance in walking, rising from a chair, climbing stairs, and falls) as well as higher scores was related to greater risks. Generalized additive models were conducted to examine the nonlinear relationships between sleep parameters and sarcopenia risks. RESULTS: The covariate-adjusted analysis showed that a reverse J-shaped relationship for sleep duration and sarcopenia risk (P < .001) and a significant association for wake time and the SARC-F score (P = .009) in total sample, with considering age-related interaction. No associations were found in the other sleep parameters (bedtime and midsleep time) and sarcopenia in older adults. Similar associations were observed between wake time and the SARC-F score across age groups, while diverse associations of sleep duration with the SARC-F score were found in different age groups. CONCLUSIONS: The sleep pattern is significantly associated with sarcopenia risks in aging adults. Improving inappropriate sleep behaviors in older adults is suggested to prevent a decline in muscle function and promote healthy aging. CITATION: Huang W-C, Lin C-Y, Togo F, et al. Nonlinear associations between sleep patterns and sarcopenia risks in older adults. J Clin Sleep Med. 2022;18(3):731-738.

Effectiveness of Facebook Remote Live-Streaming-Guided Exercise for Improving the Functional Fitness of Community-Dwelling Older Adults.

Background: The aim of this study was to determine the effect of Facebook remote live-streaming-guided exercise on the functional fitness of community-dwelling older adults. Method: This study used a non-randomized controlled design with single-blinding (outcome assessors). Older adults (mean age = 70.36 ± 4.51 years) were assigned to either the experimental group (n = 39) or the control group (n = 34). The experimental group participated in a 75-min Facebook remote live-streaming-guided exercise routine twice a week for 8 weeks at home, whereas the control group maintained their original lifestyle without any intervention. Functional fitness was assessed using the Senior Fitness Test, which assessed upper and lower limb flexibility and muscle strength, cardiorespiratory fitness, and balance. The test was administered before and after the intervention. Results: The results revealed that an 8-week Facebook remote live-streaming-guided exercise intervention increased lower limb flexibility and muscle strength and cardiorespiratory fitness in community-dwelling older adults. Conclusion: The current findings suggest that a home-based exercise program using the Facebook platform may be a feasible method to broadly improve the functional fitness of community-dwelling older adults.

Sustained Effects of Acute Resistance Exercise on Executive Function in Healthy Middle-Aged Adults.

The present study examined the sustained effects of acute resistance exercise on inhibitory function in healthy middle-aged adults. Seventy healthy middle-aged adults (mean age = 46.98 ± 5.70 years) were randomly assigned to exercise or control groups, and the Stroop test was administered before, immediately after, and 40 min after exercise. The resistance exercise protocol involved two sets of seven exercises performed for a maximum of 10 repetitions, with 60 s between sets and exercises. Acute resistance exercise resulted in higher Stroop test performance under the incongruent (inhibition) and interference conditions immediately post-exercise and 40 min post-exercise. Furthermore, the difference in scores after 40 min was significant. The findings indicate that a moderately intensive acute resistance exercise could facilitate Stroop performance and has a more beneficial effect on sustaining of cognition that involves executive control at least 40 min.

Is Sleep Timing Related to Objectively Measured Physical Activity and Sedentary Behavior in Older Women?

PURPOSE: Sleep, sedentary behavior, and physical activity are the components of the 24-hour model, while the timing of sleep may play a critical role to impact waking behaviors. Therefore, the present study aimed to examine the relationship of sleep timing with sedentary behavior, light-intensity, moderate-to-vigorous-intensity physical activity, and daily steps in older women. PATIENTS AND METHODS: A total of 90 community-dwelling older women (70.5 ± 5.4 years) were included in our sample. Multiple linear regression models were used to estimate the associations of accelerometer-measured sedentary behavior and physical activity metrics with the three sleep timing indicators (bedtime and wake time, and mid-sleep time). Bedtime and wake time were recorded by the participants, and mid-sleep time was estimated based on the two sleep indicators. RESULTS: Most indicators of sleep timing were negatively associated with moderate-to-vigorous-intensity physical activity (unstandardized coefficient [B]-0.07 for bedtime and mid-sleep time, p<0.05) and daily steps (B ranged from -15.51 for bedtime to -13.73 for wake time, p<0.05). No associations of sleep timing were found in sedentary behavior and light-intensity physical activity. CONCLUSION: The findings suggest that sleep timing should be considered when designing promising strategies or interventions for older women to be physically active.

Is achieving 7,000 steps/day cross-sectionally and prospectively associated with older adults' lower-extremity performance?

BACKGROUND: Evidence regarding the association between daily steps recommendation and older adults' lower limb strength is lacking; thus, this study investigated whether taking at least 7,000 steps/day is cross-sectionally and prospectively related to lower-extremity performance in older Taiwanese adults. METHODS: There were 89 community-dwelling adults aged over 60 years (mean age: 69.5 years) attending both baseline and follow-up surveys. This study used adjusted logistic regression analysis to explore cross-sectional and prospective relationships between their accelerometer-assessed daily steps and lower-extremity performance (five-times-sit-to-stand test). RESULTS: This study found the older adults who took 7,000 steps/day were more likely to have better lower-extremity performance cross-sectionally (odds ratio [OR] = 3.82; 95 % confidence interval [CI]: 1.04, 13.95; p = 0.04), as well as to maintain or increase their lower-extremity performance prospectively (OR = 3.53; 95 % CI: 1.05, 11.84; p = 0.04). CONCLUSIONS: Our findings support a minimum recommended level of step-based physical activity for older adults, namely, 7,000 steps/day, as beneficial for maintaining or increasing older adults' lower-extremity performance.

Is functional fitness performance a useful predictor of risk of falls among community-dwelling older adults?

BACKGROUND: Falls among older adults are a serious public health problem. Many studies indicate that positive functional fitness performance decreases the risk of falls. A limited amount of previous study has investigated the association between broad functional fitness and the fall risk. This study examines the associations between functional fitness and the risk of falling among community-dwelling older adults. METHODS: Three waves of cross-sectional data were collected from 2017 to 2019 in Taipei City, Taiwan. Six hundred sixty-five participants aged ≥65 years were randomly recruited from 12 districts of Taipei. Eight functional fitness tests (i.e., back scratch, chair-sit and-reach, 8-ft up-and-go, 30-s sit-to-stand, 30-s arm curl, 30-s single-leg stance, 2-min step, and hand grip strength tests) were performed to record the physical performance of older subjects. A Chinese version of the fall-risk questionnaire (FRQ) was used to calculate the fall risk scores. Linear regression and logistic regression were utilized to estimate the relationships of each functional fitness and fall risk. RESULT: The results showed that 37.45% of older adults had a high risk of falling. It was found for each functional fitness that performance was linearly associated with the risk of falling. Moreover, older adults with low-performance levels in all functional fitness except back-scratching were more likely to have a higher risk of falling. CONCLUSIONS: Our study indicated that functional fitness performance appears to provide valid predictive guidance for reducing the risk of falling among the older population.

Sleep duration and timing are nonlinearly associated with depressive symptoms among older adults.

BACKGROUND: Geriatric depression is a common but preventable psychiatric disorder; however, its association with specific sleep patterns remains unclear. Therefore, we examined the association of self-reported sleep duration and sleep timing with depressive symptoms in the older population. METHODS: A total of 1068 older Taiwanese adults (52.7% women; 72.2 ± 5.7 y) responded to a telephone survey during 2019-2020. Self-reported data on sociodemographic characteristics, sleep duration, bedtime, wake-up time (adapted items from Pittsburgh Sleep Quality Index), and depressive symptoms (five-item Center for Epidemiological Studies-Depression scale) were included. Generalized additive models were used to examine the nonlinear associations of sleep duration and midpoint sleep time (ie, the midpoint of bedtime and wake-up time) with depressive symptoms. RESULTS: The means of sleep duration and midpoint sleep time in the participants were 6 h per night and 02:13 h, respectively. The results showed marked nonlinear associations of sleep patterns with depressive symptoms. Sleep duration shorter than 4 h per night was associated with a relatively higher level of depressive symptoms, with the highest risk (coefficient = 3.41; 95% confidence interval [CI] = 2.12, 4.70) while sleeping 2.06 h per night. The midpoint sleep time was positively associated with depressive symptom scores after 01:00 h. CONCLUSIONS: The results showed that sleep duration and fitting sleep timing were nonlinearly associated with the risks of depressive symptoms in the general older adult population. These findings have implications for targeting nonpharmacological approaches by tackling modifiable behaviors, such as adequate sleep duration and timing, with decreased risks of depressive symptoms in the older adult population.

Association between objectively measured sleep duration and physical function in community-dwelling older adults.

STUDY OBJECTIVES: The aim of this research was to investigate the relationships between objectively measured sleep duration and physical function in older adults. METHODS: We recruited community-dwelling older adults aged ≥ 60 years old in Taipei City, Taiwan. Sleep duration was measured with accelerometers and recorded as the total hours of sleep per night for each participant. The following physical functions were assessed: 1) grip strength (measured by handgrip dynamometer), 2) balance (1-leg standing test), 3) lower body strength (5-timed chair stand), 4) basic mobility (timed up and go test), 5) gait speed (5-m walk test). The relationships between sleep duration and physical function outcomes were analyzed using generalized additive models, controlling for objectively measured sedentary behavior and moderate-to-vigorous physical activity, and other sociodemographic variables. RESULTS: A total of 121 older adults (men = 28.9%; mean age = 70.0 ± 5.0 years) was included in this study. A positive association of sleep duration with grip strength was found after adjusting for covariates (P = .005). No significant associations were observed between sleep duration and the other physical function outcomes. CONCLUSIONS: For older adults, lengthening their sleep duration may be helpful to enhance the grip strength. This result has implications for improving their health by targeting better performance in specific physical functions. Further studies of sleep duration and physical function among older adults should investigate the underlying mechanisms.

A dose response relationship between accelerometer assessed daily steps and depressive symptoms in older adults: a two-year cohort study.

OBJECTIVES: this study investigated the prospective associations of accelerometer assessed daily steps with subsequent depressive symptoms in older adults. METHODS: a 2-year prospective study was performed in the community. A total of 285 older adults ≥65 years (mean age = 74.5) attended the baseline assessment in 2012. The second wave of assessment was carried out in 2014 including 274 (96.1%) participants. Daily step counts were measured with a triaxial accelerometer (ActiGraph GT3X+), and participants were divided into three categories (<3,500, 3,500-6,999 and ≥ 7,000 steps/day). The 15-item Geriatric Depression Scale was used to measure depressive symptoms. Negative binomial regression models with multivariable adjustment for covariates (baseline depressive symptoms, accelerometer wear time, age, gender, education, chronic disease, activities of daily living) were conducted to examine the association between daily steps and subsequent depressive symptoms. RESULTS: each 1,000-step increase in daily walking was linearly associated with a reduced rate of subsequent depressive symptoms (rate ratio [RR] = 0.95, 95% confidence interval [CI] = 0.92-0.98). Participants with daily step count in 3,500-6,999 (RR = 0.84, 95% CI = 0.70-0.99) and ≥7,000 steps (RR = 0.71, 95% CI = 0.55-0.92) per day had fewer depressive symptoms at follow-up. Sensitivity analyses assessing confounding and reverse causation provided further support for the stability of our findings. CONCLUSION: older adults engaging in more daily steps had fewer depressive symptoms after 2 years. Even as few as 3,500-6,999 steps a day was associated with a protecting effect. Accumulating ≥7,000 steps a day could provide the greatest protection against depressive symptoms.