The descriptive epidemiology of the diurnal profile of bouts and breaks in sedentary time in older English adults

Morning physical activity may be more beneficial for blood lipids than afternoon physical activity in older adults: a cross-sectional study

BACKGROUND

The effect of differences in daily physical activity patterns on blood lipids has not been determined. This study examines the effects of the differences in free-living daily physical activity patterns (amount and intensity) on blood lipid levels in older adults.

METHODS

This cross-sectional study included 51 older participants (71.8 ± 0.6 years, men = 8, women = 43). A triaxial accelerometer was used to assess physical activity patterns. The time from awakening to bedtime for each participant was used for group classification based on the amount (number of steps) and intensity (moderate-to-vigorous physical activity, MVPA) of physical activity. The morning step group (M Step) was defined as those who took more steps in the morning, and the afternoon step group (A Step) was defined as those who took more steps in the afternoon. The same method was used for MVPA (morning MVPA: M MVPA; afternoon MVPA: A MVPA). Blood samples were collected at the start of the study to determine blood lipid levels.

RESULTS

Number of steps taken showed a trend toward lower low-density lipoprotein cholesterol (LDL-C) levels in the M Step group compared with the A Step group. The LDL/high-density lipoprotein (HDL) ratio was significantly lower in the M Step group than the A Step group (p < 0.05). The M MVPA group also had higher HDL-C levels and significantly lower LDL/HDL ratios than the A MVPA group (p < 0.05).

CONCLUSIONS

These results suggest that compared with afternoon physical activity, daily morning physical activity (amount and intensity) is more effective in improving blood lipid levels.

Unravelling upright events: a descriptive epidemiology of the behavioural composition and temporal distribution of upright events in participants from the 1970 British Cohort Study

BACKGROUND

Continued proliferation of accelerometers in physical activity research has opened new avenues for understanding activity behaviours beyond simple aggregate measures of frequency and duration. This study explores the standing and stepping composition, and the temporal distribution, of upright events, and investigates their associations with sociodemographic and health factors.

METHODS

Participants from the 1970 British Cohort Study wore activPAL3 accelerometers for seven days. Event-based analysis was used to extract a time series of upright, standing, and stepping events. Derived metrics included daily number of upright and stepping events, total upright and stepping time, the burstiness of upright events and burstiness of sedentary events (burstiness refers to the pattern of how physical activity and sedentary behaviour are distributed throughout a given time period), within-event stepping proportion, within-event step count, and stepping cadence. Generalized linear regression models, adjusted for total step count, were employed to explore associations between derived metrics and sociodemographic and health-related factors.

RESULTS

A total of 4527 participants, provided 30992 valid days (≥ 10 h of waking wear) and 1.64 million upright events. Upright event composition and temporal distribution varied across a range of sociodemographic and health-related factors. Females had more upright events than males (4.39 [3.41,5.38] n), spent more time upright, and exhibited burstier patterns of upright events (0.05 [0.04,0.05] Bn). Individuals with higher BMI had fewer upright events and a lower daily step count, but their temporal distribution of upright events was less bursty (overweight -0.02 [-0.02,-0.01] Bn; obese -0.03 [-0.04,-0.02] Bn), and upright events had a higher step count. People in active occupations were upright for longer, displayed burstier patterns of upright events (standing 0.04 [0.03,0.05] Bn; physical work 0.05 [0.04,0.05] Bn; heavy manual 0.06 [0.04,0.07] Bn), with more variable durations and shorter, slower paced stepping events compared with sedentary occupations.

CONCLUSIONS

This study has revealed novel phenotypes of standing and sitting that go beyond simple aggregate measures of total steps, step event duration or time between events. People with the same volume of stepping and frequency of gaps between upright events can accumulate their steps in very different ways. These differences and associations with population sub-groups, which persisted after adjustment for total stepping volume, may have important relations with functional and health outcomes. The findings lay the groundwork for future studies to investigate how different sitting and standing phenotypes can add to our understanding of the relationship between physical activity and health.

Accelerometry-assessed physical activity and sedentary behavior patterns using single- and multi-component latent class analysis among postmenopausal women

BACKGROUND

Patterns of physical activity and sedentary behavior among postmenopausal women are not well characterized.

OBJECTIVES

To describe the patterns of accelerometer-assessed physical activity and sedentary behavior among postmenopausal women.

DESIGN

Cross-sectional study.

METHODS

Women 63-97 years (n = 6126) wore an ActiGraph GT3X + accelerometer on their hip for 1 week. Latent class analysis was used to classify women by patterns of percent of wake time in physical activity and sedentary behavior over the week.

RESULTS

On average, participants spent two-thirds of their day in sedentary behavior (62.3%), 21.1% in light low, 11.0% in light high, and 5.6% in moderate-to-vigorous physical activity. Five classes emerged for each single-component model for sedentary behavior and light low, light high, and moderate-to-vigorous physical activity. Six classes emerged for the multi-component model that simultaneously considered the four behaviors together.

CONCLUSION

Unique profiles were identified in both single- and multi-component models that can provide new insights into habitual patterns of physical activity and sedentary behavior among postmenopausal women.

IMPLICATIONS

The multi-component approach can contribute to refining public health guidelines that integrate recommendations for both enhancing age-appropriate physical activity levels and reducing time spent in sedentary behavior.

Day-of-the-Week and Time-of-the-Day Patterns of Sedentary Behavior in the Hispanic Community Health Study/Study of Latinos

PURPOSE

Existing sedentary behavior interventions have largely achieved mixed results. Conventionally, interventions have attempted to reduce sedentary behavior using a full-day approach. An alternative strategy may be to target specific periods during the day and/or week. This study examined the day-of-the-week (Monday to Sunday) and time-of-the-day patterns (3-and 6-h periods) of sedentary behavior among U.S. Hispanics/Latinos adults.

METHODS

Participants ( n = 12,241) from the Hispanic Community Health Study/Study of Latinos, a multisite community-based prospective cohort study of Hispanic/Latino adults, were studied. Sedentary behavior was assessed for 1 wk using a hip-mounted accelerometer through total sedentary time, sedentary time in bouts ≥60 min, and total number of sedentary breaks. The temporal patterns of sedentary behavior metrics were evaluated using linear mixed effect models accounting for the Hispanic Community Health Study/Study of Latinos complex survey design.

RESULTS

There were statistically significant variations in temporal patterns across day-of-the-week and time-of-the-day periods for all three metrics ( P < 0.001). Adults were more sedentary on weekends than on weekdays and most sedentary on Sundays. The time-of-the-day patterns had a U-curve pattern wherein adults were most sedentary late at night, became less sedentary throughout the day, reached peak activeness around noon, then gradually became more sedentary into the evening. These patterns were largely robust across seasonality and most sociodemographic characteristics, including age, employment status, work shift schedule, acculturation, and field center.

CONCLUSIONS

Our findings suggest that early mornings, evenings, and weekends were the more sedentary periods in this cohort of Hispanic/Latino adults, characterized by higher volumes of sedentary time, higher volumes of time in prolonged sedentary bouts, and fewer number of sedentary breaks than other time periods, highlighting important windows of opportunity to reduce sedentary behavior.

Prolonged bouts of sedentary behavior in people with chronic obstructive pulmonary disease and associated factors

BACKGROUND

Increased sedentary behavior (SB), especially in prolonged bouts, is associated with adverse health outcomes, but little is known about patterns of SB in people with chronic obstructive pulmonary disease (COPD).

OBJECTIVES

The purpose of this study was to describe SB and patterns of SB and to examine factors associated with prolonged bouts of SB in inactive community-dwelling adults with COPD.

METHODS

This cross-sectional analysis used data from inactive adults with COPD who were enrolled in an exercise program but had not started exercising. Participants were ≥ 50 years old with a diagnosis of COPD, had a forced expiratory volume in one second < 80% predicted, and were inactive. Participants wore an activPAL device for seven days to measure their SB and completed surveys and physical measures. Data were analyzed with multiple regression.

RESULTS

The sample included 160 participants with a mean age (± SD) of 69 ± 8, and a mean total sedentary time of 742 ± 150 min/day, with 254 ± 146 min/day in SB bouts ≥ 60 min.

DURATION

Time spent in bouts of SB ≥ 60-min. was negatively associated with self-efficacy for overcoming barriers to light physical activity (P<0.05), balance (P<0.05), chair stand test (P<0.05), FEV1% predicted (P<0.05) and positively associated with BMI (P<0.001).

CONCLUSIONS

Inactive people with COPD engage in extensive SB, much of it in prolonged bouts. Self-efficacy, balance, and lower body strength are modifiable variables associated with SB and potential targets for future interventions to reduce time in prolonged sedentary behavior.

Device-measured physical activity and sedentary time in a national sample of Luxembourg residents: the ORISCAV-LUX 2 study

BACKGROUND

Existing information about population physical activity (PA) levels and sedentary time in Luxembourg are based on self-reported data.

METHODS

This observational study included Luxembourg residents aged 18-79y who each provided ≥4 valid days of triaxial accelerometry in 2016-18 (n=1122). Compliance with the current international PA guideline (≥150 min moderate-to-vigorous PA (MVPA) per week, irrespective of bout length) was quantified and variability in average 24h acceleration (indicative of PA volume), awake-time PA levels, sedentary time and accumulation pattern were analysed by linear regression. Data were weighted to be nationally representative.

RESULTS

Participants spent 51% of daily time sedentary (mean (95% confidence interval (CI)): 12.1 (12.0 to 12.2) h/day), 11% in light PA (2.7 (2.6 to 2.8) h/day), 6% in MVPA (1.5 (1.4 to 1.5) h/day), and remaining time asleep (7.7 (7.6 to 7.7) h/day). Adherence to the PA guideline was high (98.1%). Average 24h acceleration and light PA were higher in women than men, but men achieved higher average accelerations across the most active periods of the day. Women performed less sedentary time and shorter sedentary bouts. Older participants (aged ≥55y) registered a lower average 24h acceleration and engaged in less MVPA, more sedentary time and longer sedentary bouts. Average 24h acceleration was higher in participants of lower educational attainment, who also performed less sedentary time, shorter bouts, and fewer bouts of prolonged sedentariness. Average 24h acceleration and levels of PA were higher in participants with standing and manual occupations than a sedentary work type, but manual workers registered lower average accelerations across the most active periods of the day. Standing and manual workers accumulated less sedentary time and fewer bouts of prolonged sedentariness than sedentary workers. Active commuting to work was associated with higher average 24h acceleration and MVPA, both of which were lower in participants of poorer self-rated health and higher weight status. Obesity was associated with less light PA, more sedentary time and longer sedentary bouts.

CONCLUSIONS

Adherence to recommended PA is high in Luxembourg, but half of daily time is spent sedentary. Specific population subgroups will benefit from targeted efforts to replace sedentary time with PA.

The role of socio-demographic factors and physical functioning in the intra- and interpersonal variability of older adults' sedentary time: an observational two-country study

BACKGROUND

Insight into the variability of older adults' sedentary time is needed to inform future interventions. The aim of this study was to examine the intra- and interpersonal variability in sedentary time, and the moderating role of socio-demographics, physical functioning and geographical location in this variability.

METHODS

Cross-sectional data from 818 community-dwelling older adults (mean age: 74.8 years; 61.1%women) of the Active Lifestyle and the Environment in Chinese Seniors and Belgian Environmental Physical Activity Study in Seniors were used. An interview questionnaire was administered to collect socio-demographic information. The Short Physical Performance Battery was performed to evaluate physical functioning, and Actigraph GT3X( +) accelerometers were used to estimate sedentary time. Linear mixed models with random intercepts at the neighborhood, person and day levels examined the variability in sedentary time, and the moderating role of socio-demographics, physical functioning and geographical location within this variability.

RESULTS

Most of the variance in accelerometry-assessed sedentary time was due to intrapersonal variability across periods of the day (72.4%) followed by interpersonal variability within neighborhoods (25.6%). Those who were older, men, lived in Hong Kong, and experienced a lower level of physical functioning were more sedentary than their counterparts. Sedentary time increased throughout the day, with highest levels of sedentary time observed between 6:00 and 9:00 pm. The patterns of sedentary time across times of the day differed by gender, educational attainment, age, physical functioning and/or geographical location. No significant differences were detected between week and weekend day sedentary time.

CONCLUSIONS

The oldest old, men, and those with functional limitations are important target groups for sedentary behavior interventions. As sedentary time was the highest in the evening future sedentary behavior intervention should pay particular attention to the evening hours. The variations in diurnal patterns of sedentary time between population subgroups suggest that personalized just-in-time adaptive interventions might be a promising strategy to reduce older adults' sedentary time.

Association of Accelerometer-Measured Sedentary Accumulation Patterns With Incident Cardiovascular Disease, Cancer, and All-Cause Mortality

Background Emerging evidence suggests accruing sedentary behavior (SB) in relatively more prolonged periods may convey additional cardiometabolic risks, but few studies have examined prospective outcomes. We examined the association of SB accumulation patterns with incident cardiovascular disease (CVD), cancer, and all-cause mortality (ACM). Methods and Results Data were from 7671 EPIC-Norfolk (European Prospective Investigation Into Cancer and Nutrition-Norfolk) cohort middle- to older-aged adults who wore accelerometers on the right hip for 4 to 7 days. Cox proportional hazards regression modeled associations between 2 measures of SB accumulation and incident CVD, cancer, and ACM. These were usual SB bout duration (the midpoint of each individual's SB accumulation curve, fitted using nonlinear regression) and alpha (hybrid measure of bout frequency and duration, with higher values indicating relatively shorter bouts and fewer long bouts). Models were adjusted for potential confounders, then further for 24-hour time-use compositions. During mean follow-up time of 6.4 years, 339 ACM, 1106 CVD, and 516 cancer events occurred. Elevated rates of incident cancer and ACM were seen with more prolonged SB accumulation (lower alpha, higher usual SB bout duration) but not CVD. For usual SB bout duration and alpha, respectively, the confounder-adjusted hazard ratios per SD of the exposure were 1.12 (95% CI, 1.02-1.23) and 0.88 (95% CI, 0.79-0.98) with incident cancer and 1.16 (95% CI, 1.07-1.26) and 0.80 (95% CI, 0.72-0.89) with ACM (all P<0.05). Further adjustment for 24-hour time use weakened associations with ACM for usual bout duration (hazard ratio, 1.06; 95% CI, 0.97-1.16; P=0.209) and partially for alpha (hazard ratio, 0.87; 95% CI, 0.77-0.99; P=0.029). Conclusions Accruing SB in longer bout durations was associated with higher rates of incident cancer and ACM but not with incident CVD, with some evidence of direct SB accumulation effects independent of 24-hour time use. Findings provide some support for considering SB accumulation as an adjunct target of messaging to "sit less and move more."

Exploring Potential Benefits of Accumulated Multicomponent-Training in Non-Active Older Adults: From Physical Fitness to Mental Health

The present study aimed to analyze the impact of a multicomponent training (MCT) program in a group of non-active older adults, comparing two different dose distributions. Twenty-four individuals, assigned to two groups, completed 15 weeks of MCT (2 days/week). The continuous group (CMCT; n = 14, 9 females; 71.07 ± 5.09 years) trained for 60 min/session in the morning. The accumulated group (AMCT; n = 10, 5 females; 72.70 ± 3.59 years) performed the same exercises, volume, and intensity, but the training was distributed twice per day (30 min in the morning; 30 more in the afternoon). Bonferroni post hoc comparisons revealed significant (p < 0.001) and similar large improvements in both groups in lower limb strength (five times sit-to-stand test: CMCT, 12.55 ± 2.83 vs. 9.44 ± 1.72 s; AMCT, 10.37 ± 2.35 vs. 7.46 ± 1.75 s). In addition, there were large gains in preferred walking speed and instrumental daily life activities, which were higher for CMCT and AMCT, respectively (in this order: 1.00 ± 0.18 vs. 1.44 ± 0.26 m/s and 1.09 ± 0.80 vs. 1.58 ± 0.18 m/s; 33.07 ± 2.88 vs. 36.57 ± 1.65 points and 32.80 ± 1.93 vs. 36.80 ± 0.92 points); improvements in cardiorespiratory fitness, now moderate for CMCT (474.14 ± 93.60 vs. 529.64 ± 82.76 m) and large for AMCT (515.10 ± 20.24 vs. 589.60 ± 40.38 m); and medium and similar enhancements in agility in both groups (TUG test: CMCT: 7.49 ± 1.11 vs. 6.77 ± 1.16 s; AMCT: 6.84 ± 1.01 vs. 6.18 ± 0.62 s). None of the protocols had an impact on the executive function, whereas health-related quality of life showed a trend to significance in the whole sample only (EQindex overall sample, p = 0.062; d = 0.48 CMCT; d = 0.34 AMCT). Regardless of the type of dose distribution, starting multicomponent training improves physical function in non-active older adults, but does not improve cognitive function at mid-term. Because both forms of MCT showed similar compliance, slightly positive differences in accumulated strategies may indicate some benefits related to breaking afternoon sedentary behaviors, which deserves further research in longer and larger interventions. The mixed nature of MCT suggests accumulative group interventions may be a promising approach to address sedentary aging.

Descriptive Epidemiology of Interruptions to Free-Living Sitting Time in Middle-Age and Older Adults

National guidelines recommend physically active interruptions to sitting time, however, the characteristics of these interruptions are broadly stated and ill-defined. A robust methodology for population surveillance for such interruptions is needed.

PURPOSE

To describe the frequency and characteristics (i.e., duration, stepping time, and estimated intensity) of all interruptions and physically active interruptions to adults' free-living sitting time (i.e., transitions from sitting to upright posture) across segments of the population.

METHODS

Australian Diabetes, Obesity and Lifestyle (AusDiab) study participants (321 men; 406 women; mean ± SD 58.0 ± 10.3 years) wore the activPAL3TM for ≥1 valid day. The characteristics of interruptions from laboratory studies demonstrating health benefits were selected to define active interruptions (≥5 min upright and/or ≥ 2 min stepping) and ambulatory interruptions (≥2 min stepping). The frequency and characteristics of all, active, and ambulatory interruptions were described and compared by age, gender, diabetes status, and body mass index.

RESULTS

Adults averaged 55.0 ± 21.8 interruptions per day, but only 20.3 ± 6.7 were active and 14.0 ± 5.4 were ambulatory. Median (25th, 75th percentile) duration was 2.6 (0.9, 7.8) minutes, stepping time was 0.8 (0.3, 2.0) minutes, and estimated energy expenditure was 4.3 (1.4, 12.5) MET-min. Those who were older, had obesity, or had diabetes had significantly (p < 0.05) fewer interruptions of all types and less stepping time during active interruptions than their counterparts (Cohen's d < 0.2).

CONCLUSION

Free-living interruptions were often less active than interruptions performed in effective acute laboratory studies and their content varied widely between population groups. Monitoring all interruptions as well as those that are more active is advisable to provide a comprehensive understanding of free-living sedentary behavior.

Association between walking energetics and fragmented physical activity in mid-to-late life

BACKGROUND

Physical activity becomes increasingly fragmented with age, which may be an early marker of functional decline. Energetic cost of walking and energy capacity are also linked with functional decline, but their associations with activity fragmentation, and the potential modifying roles of total daily physical activity and age, remains unclear.

METHODS

493 participants (50-93 years) from the Baltimore Longitudinal Study of Aging underwent measures of: energetic cost of usual-paced overground walking (ml/kg/m), energy demand during slow walking (ml/kg/min) on a treadmill (0.67 m/s, 0% grade),m/s, 0% grade), and average peak walking energy expenditure (ml/kg/min) during a fast-paced 400-m walk. A ratio of slow walking to peak walking energy expenditure ("cost-to-capacity ratio") was calculated. Activity fragmentation was quantified as an active-to-sedentary transition probability (ASTP) using Actiheart accelerometer data. Linear regression models with ASTP as the dependent variable were used to test whether poorer energy cost and capacity were associated with higher ASTP and whether the associations differed by daily physical activity or age.

RESULTS

After adjusting for demographics, body composition, comorbidities and daily physical activity, every 10% higher cost-to-capacity ratio was associated with 0.4% greater ASTP (p=0.005). This association was primarily driven by the least active participants (pinteraction=0.023). Peak walking energy expenditure was only associated with ASTP among participants aged ≥70 years.

CONCLUSIONS

Higher cost-to-capacity ratio and lower energy capacity may manifest as more fragmented physical activity, especially among those less active or aged ≥70 years. Future studies should examine whether an increasing cost-to-capacity ratio or declining energy capacity predicts subsequent activity fragmentation.

Objectively Measured Sedentary Time Before and After Transition to Retirement: The Finnish Retirement and Aging Study

BACKGROUND

Retirement is associated with an increase in self-reported daily sedentary time, but no longitudinal evidence exists on how objectively measured sedentary time changes during retirement transition. The aim of this study was to compare objectively measured daily and hourly sedentary time before and after retirement and examine whether these changes differ by gender and occupational status.

METHODS

The study population consisted of 478 participants (mean age 63.2 years, standard deviation 1.7, 85% women) from the Finnish Retirement and Aging Study. Sedentary time was measured using a wrist-worn triaxial ActiGraph accelerometer before and after transition to retirement with 1 year interval. Preretirement occupational status was categorized as manual and non-manual.

RESULTS

Daily sedentary time was 8 hours 10 minutes in women and 9 hours 49 minutes in men before retirement. Considering all measurement days before and after retirement, daily sedentary time increased in women by 29 minutes (95% confidence interval [CI]: 20 to 38). Especially women retiring from manual occupations showed marked increase in sedentary time (63 minutes, 95% CI: 50 to 77). When only non-working days before retirement were considered, increase in daily sedentary time among women was less marked (16 minutes, 95% CI: 7 to 25). Among men, daily sedentary time did not change in retirement transition (-7 minutes, 95% CI: -26 to 12).

CONCLUSIONS

Objectively measured sedentary time increases among women and remains at high level among men during the retirement transition. Attention should be paid to reduce daily sedentary time in retiring women and men.

Associations of older adults' excursions from home with health-related physical activity and sedentary behavior

BACKGROUND

As people age, they spend more time in and around their domestic environments, within which opportunities for health-enhancing physical activity (PA) may be limited. We examined the associations of frequency of excursions from home with accelerometer-determined PA and the total and prolonged sedentary behavior (SB, sitting for ≥30 min) among community-dwelling older adults.

METHODS

Overall, 434 older adults (men, 57.1 %; age, 70-79 years) wore an accelerometer (HJA-350IT, Omron Healthcare) for 7 days. Time spent in SB, light-intensity PA (LPA), moderate-to-vigorous PA (MVPA), and prolonged SB bout (≥30 min) were calculated. Frequencies of excursions from home were categorized as 0-3, 4-5, and 6-7 days/week. Associations of excursions with PA and SB were tested by analysis of covariance adjusted for sociodemographic characteristics.

RESULTS

Frequencies were 14.3 %, 31.1 %, and 54.6 % for excursions 0-3, 4-5, and 6-7 days/week, respectively. For men, less frequent excursions from home were significantly associated with less MVPA and more total and prolonged SB times (estimated means [minutes/day]: MVPA, 32, 42, and 48; total SB, 589, 549, and 539; prolonged SB, 344, 288, and 265; respectively; p < 0.05). LPA was not statistically significant (p = 0.09). For women, less frequent excursions were significantly associated with all PA outcomes (SB: 536, 497, and 467; prolonged SB: 260, 213, and 204; LPA: 328, 363, and 379; MVPA: 36, 39, and 54, respectively).

CONCLUSIONS

Among community-dwelling Japanese older adults, more frequent excursions from home were associated with more PA, less SB, and more-favorable SB patterns, suggesting a potential strategy for preventive-health initiatives.

Continuous Compared to Accumulated Walking-Training on Physical Function and Health-Related Quality of Life in Sedentary Older Persons

The present study aimed to analyze the impact of overground walking interval training (WIT) in a group of sedentary older adults, comparing two different dose-distributions. In this quasi-experimental and longitudinal study, we recruited twenty-three sedentary older adults (71.00 ± 4.10 years) who were assigned to two groups of WIT. The continuous group (CWIT) trained for 60 min/session in the morning, while the accumulated group (AWIT) performed the same duration and intensity of exercise, but it was distributed twice a day (30 min in the morning and 30 more in the afternoon). After 15 weeks of an equal external-load training (3 days/week), Bonferroni post-hoc comparisons revealed significant (p < 0.050) and similar large improvements in both groups in cardiorespiratory fitness and lower limb strength; even larger gains in preferred walking speed and instrumental daily life activity, which was slightly superior for CWIT; and improvements in agility, which were moderate for CWIT and large for AWIT. However, none of the training protocols had an impact on the executive function in the individuals, and only the AWIT group improved health-related quality of life. Although both training protocols induced a general significant improvement in physical function in older adults, our results showed that the accumulative strategy should be recommended when health-related quality of life is the main target, and the continuous strategy should be recommended when weakness may be a threat in the short or medium term.

Diurnal patterns of sedentary time in rheumatoid arthritis: associations with cardiovascular disease risk

Objectives

Research demonstrates that sedentary behaviour may contribute towards cardiovascular disease (CVD) risk in rheumatoid arthritis (RA). This study explored diurnal patterns of sedentary time and physical activity (PA) in RA and examined associations with long-term CVD risk.

Methods

97 RA patients wore an accelerometer for 7 days to assess sedentary time, light-intensity and moderate-to-vigorous-intensity PA. Estimated 10-year CVD risk was determined via QRISK score. Hourly estimates of sedentary time and PA (min/hour) were computed for valid-wear hours (ie, valid-wear = 60 min/hour of activity data, ≥3 days). Hourly data were averaged across time periods to represent morning (08:00–11:59), afternoon (12:00–17:59) and evening (18:00–22:59) behaviour. Participants providing data for ≥2 complete time periods/day (eg, morning/evening, or morning/afternoon) were used in the main analysis (n = 41). Mixed linear modelling explored the associations between 10-year CVD risk and within-person (time: morning, afternoon, evening) changes in sedentary time and PA.

Results

Sedentary time was higher, and light-intensity and moderate-to-vigorous-intensity PA lower in the evening, compared to morning and afternoon. Significant interactions revealed individuals with higher CVD risk were more sedentary and did less light-intensity PA during the afternoon and evening. Findings remained significant after adjustment for disease duration, functional ability and erythrocyte sedimentation rate.

Conclusion

Results suggest that the evening time period may offer a significant window of opportunity for interventions to reduce sedentary behaviour in RA and contribute to associated improvements in CVD risk. Due to inverse patterns of engagement, replacing sedentary time with light-intensity PA may offer an effective approach for intervention.

Diurnal patterns of sedentary behavior and changes in physical function over time among older women: a prospective cohort study

BACKGROUND

Sedentary behavior (SB) is linked to negative health outcomes in older adults. Most studies use summary values, e.g., total sedentary minutes/day. Diurnal timing of SB accumulation may further elucidate SB-health associations.

METHODS

Six thousand two hundred four US women (mean age = 79 ± 7; 50% White, 34% African-American) wore accelerometers for 7-days at baseline, yielding 41,356 person-days with > 600 min/day of data. Annual follow-up assessments of health, including physical functioning, were collected from participants for 6 years. A novel two-phase clustering procedure discriminated participants' diurnal SB patterns: phase I grouped day-level SB trajectories using longitudinal k-means; phase II determined diurnal SB patterns based on proportion of phase I trajectories using hierarchical clustering. Mixed models tested associations between SB patterns and longitudinal physical functioning, adjusted for covariates including total sedentary time. Effect modification by moderate-vigorous-physical activity (MVPA) was tested.

RESULTS

Four diurnal SB patterns were identified: p1 = high-SB-throughout-the-day; p2 = moderate-SB-with-lower-morning-SB; p3 = moderate-SB-with-higher-morning-SB; p4 = low-SB-throughout-the-day. High MVPA mitigated physical functioning decline and correlated with better baseline and 6-year trajectory of physical functioning across patterns. In low MVPA, p2 had worse 6-year physical functioning decline compared to p1 and p4. In high MVPA, p2 had similar 6-year physical functioning decline compared to p1, p3, and p4.

CONCLUSIONS

In a large cohort of older women, diurnal SB patterns were associated with rates of physical functioning decline, independent of total sedentary time. In particular, we identified a specific diurnal SB subtype defined by less SB earlier and more SB later in the day, which had the steepest decline in physical functioning among participants with low baseline MVPA. Thus, diurnal timing of SB, complementary to total sedentary time and MVPA, may offer additional insights into associations between SB and physical health, and provide physicians with early warning of patients at high-risk of physical function decline.

Active-to-Sedentary Behavior Transitions, Fatigability, and Physical Functioning in Older Adults

BACKGROUND

With aging, daily physical activity (PA) becomes less frequent and more fragmented. Accumulation patterns of daily PA-including transitions from active-to-sedentary behaviors-may provide important insights into functional status in older, less active populations.

METHODS

Participants of the Baltimore Longitudinal Study of Aging (n = 680, 50% male, aged 27-94 years) completed a clinical assessment and wore an Actiheart accelerometer. Transitions between active and sedentary states were modeled as a probability (Active-to-Sedentary Transition Probability [ASTP]) defined as the reciprocal of the average PA bout duration. Cross-sectional associations between ASTP and gait speed (m/s), fatigability (rating-of-perceived-exertion [RPE]), 400 m time (seconds), and expanded short physical performance battery score were modeled using linear and logistic regression, adjusted for chronic conditions. Further analyses explored the utility of ASTP over-and-above total daily PA.

RESULTS

In continuous models, each 0.10-unit higher ASTP was associated slower gait (β = -0.06 m/s, SE = 0.01), higher fatigability (β = 0.60 RPE, SE = 0.12), slower 400 m time (β = 16.31 s, SE = 2.70), and lower functioning (β = -0.13 expanded short physical performance battery score, SE = 0.03; p < .001). In categorical analyses, those in the highest tertile of ASTP were >2 times more likely to have high fatigability (rating of perceived exertion ≥10), slow 400 m time (>300 seconds) and reduced functional performance (expanded short physical performance battery score < 3.07) than those in the lowest tertile (p < .01). Further analyses demonstrated ASTP provided additional insight into functional outcomes beyond total daily PA.

CONCLUSION

Fragmented daily PA-as measured by ASTP-is strongly linked with measures of health and functional status and may identify those at risk of high fatigability and reduced functional performance over and above traditional PA metrics.

Real-time Mobile Monitoring of the Dynamic Associations Among Motor Activity, Energy, Mood, and Sleep in Adults With Bipolar Disorder

IMPORTANCE

Biologic systems involved in the regulation of motor activity are intricately linked with other homeostatic systems such as sleep, feeding behavior, energy, and mood. Mobile monitoring technology (eg, actigraphy and ecological momentary assessment devices) allows the assessment of these multiple systems in real time. However, most clinical studies of mental disorders that use mobile devices have not focused on the dynamic associations between these systems.

OBJECTIVES

To examine the directional associations among motor activity, energy, mood, and sleep using mobile monitoring in a community-identified sample, and to evaluate whether these within-day associations differ between people with a history of bipolar or other mood disorders and controls without mood disorders.

DESIGN, SETTING, AND PARTICIPANTS

This study used a nested case-control design of 242 adults, a subsample of a community-based sample of adults. Probands were recruited by mail from the greater Washington, DC, metropolitan area from January 2005 to June 2013. Enrichment of the sample for mood disorders was provided by volunteers or referrals from the National Institutes of Health Clinical Center or by participants in the National Institute of Mental Health Mood and Anxiety Disorders Program. The inclusion criteria were the ability to speak English, availability to participate, and consent to contact at least 2 living first-degree relatives. Data analysis was performed from June 2013 through July 2018.

MAIN OUTCOMES AND MEASURES

Motor activity and sleep duration data were obtained from minute-to-minute activity counts from an actigraphy device worn on the nondominant wrist for 2 weeks. Mood and energy levels were assessed by subjective analogue ratings on the ecological momentary assessment (using a personal digital assistant) by participants 4 times per day for 2 weeks.

RESULTS

Of the total 242 participants, 92 (38.1%) were men and 150 (61.9%) were women, with a mean (SD) age of 48 (16.9) years. Among the participants, 54 (22.3%) had bipolar disorder (25 with bipolar I; 29 with bipolar II), 91 (37.6%) had major depressive disorder, and 97 (40.1%) were controls with no history of mood disorders. A unidirectional association was found between motor activity and subjective mood level (β = -0.018, P = .04). Bidirectional associations were observed between motor activity (β = 0.176; P = .03) and subjective energy level (β = 0.027; P = .03) as well as between motor activity (β = -0.027; P = .04) and sleep duration (β = -0.154; P = .04). Greater cross-domain reactivity was observed in bipolar disorder across all outcomes, including motor activity, sleep, mood, and energy.

CONCLUSIONS AND RELEVANCE

These findings suggest that interventions focused on motor activity and energy may have greater efficacy than current approaches that target depressed mood; both active and passive tracking of multiple regulatory systems are important in designing therapeutic targets.