Isotemporal substitution analysis of time between sleep, sedentary behavior, and physical activity on depressive symptoms in older adults: a cross-sectional study

BACKGROUND

Compared to young individuals, older adults participate more in sedentary behavior (SB) and less in physical activity (PA). These behaviors are associated with numerous adverse health factors.

OBJECTIVE

The purpose of the study was to examine the hypothetical effects of substituting time spent sleeping, performing SB, and performing moderate-to-vigorous physical activity (MVPA) on depressive symptomatology in older adults.

DESIGN AND SETTING

An analytical cross-sectional study employing exploratory survey methods was conducted in the city of Alcobaça in the state of Bahia, Brazil.

METHODS

The study included 473 older adults who answered a structured questionnaire during an interview. Exposure time to SB and PA level were assessed using the International Physical Activity Questionnaire, and depressive symptoms were analyzed using the short version of the Geriatric Depression Scale. An isotemporal replacement model was used to evaluate the effects of different SB sessions on depressive symptomatology.

RESULTS

An increase in the risk of depressive symptoms was observed when MVPA and sleep time were substituted for the same SB time at all times tested, with maximum values of 40% and 20%, respectively. Opposite substitution of MVPA and sleep time increments reduced the risk of depressive symptomatology by 28% and 17%, respectively.

CONCLUSIONS

The results of the present study indicate that replacing SB with the same amount of sleep or MVPA may reduce depressive symptoms. The longer the reallocation time, the greater are the benefits.

Relationship between the phase angle from bioelectrical impedance analysis and daily physical activity in patients with rheumatoid arthritis

OBJECTIVES

This study aimed to examine the relationship between daily physical activity and the phase angle (PhA) obtained by bioelectrical impedance analysis in rheumatoid arthritis (RA) patients.

METHODS

Data from a prospective cohort study of RA patients who were surveyed every year were analysed. The PhA was assessed by the bioelectrical impedance analysis method, and physical activity was assessed as the amount of time of exercise in metabolic equivalents (METs) per day using a triaxial accelerometer for 7 consecutive days. The association between physical activity and the PhA was evaluated using the isotemporal substitution model in multiple regression analysis.

RESULTS

Seventy-six RA patients were included in the analysis (81% female and age 66.2 ± 13.1 years). On cross-sectional analysis, the isotemporal substitution model in multiple regression analysis showed that the PhA was 0.05 points higher every 10 minutes when activities with intensity of 1 ≤ METs < 2 were replaced by activities with intensity of ≥3 METs (P = .01). Over 1 year, the rate of change in the PhA was 0.69% higher every 10 minutes when activities with intensity of 1 ≤ METs < 2 were replaced by activities with intensity of ≥3 METs (P = .037).

CONCLUSION

The PhA in RA patients may be related to physical activity level.

The effect of different intensity physical activity on cardiovascular metabolic health in obese children and adolescents: An isotemporal substitution model

Objective: This study's purpose was to investigate the effects of different intensities of physical activity on cardiovascular metabolism in obese children and adolescents based on an isochronous replacement model. Methods: A total of 196 obese children and adolescents (mean age, 13.44 ± 1.71 years) who met the inclusion criteria and attended a summer camp from July 2019 to August 2021 were recruited for this study, and all subjects wore a GT3X + triaxial motion accelerometer uniformly around the waist to record physical activity levels. We collected the subjects' height, weight, and cardiovascular risk factors such as waist circumference, hip circumference, fasting lipids, blood pressure, fasting insulin, and fasting glucose before and after 4 weeks of camp and constructed cardiometabolic risk score (CMR-z). We analyzed the effects of different intensities of physical activity on cardiovascular metabolism in obese children using isotemporal substitution model (ISM). Results: After 4 weeks, cardiovascular risk factors such as body weight, waist circumference, triglyceride, and total cholesterol were reduced in adolescents with obesity (p <0.01), and CMR-z was also reduced (p <0.01). ISM analysis revealed that all sedentary behavior (SB) replacement with 10 min of light physical activity (LPA) reduced CMR-z [β = -0.10, 95% CI (-0.20, -0.01)]; 10-min of moderate physical activity (MPA) replacement of SB reduced CMR-z [β = -0.32, 95% CI (-0.63, -0.01)]; 10-min of vigorous physical activity (VPA) replacement of SB reduced CMR-z [β = -0.39, 95% CI (-0.66, -0.12)]. Conclusion: Replacement of SB with 10 min of LPA, MPA, and VPA were all effective in improving cardiovascular risk health, respectively, but MPA or VPA was more effective.

Moderate-to-vigorous physical activity and sedentary behavior are independently associated with renal function: a cross-sectional study

BACKGROUND

Little is known about whether insufficient moderate-to-vigorous physical activity (MVPA) and longer sedentary behavior (SB) are independently associated with estimated glomerular filtration rate (eGFR) and CKD, whether they interact with known risk factors for CKD, and the effect of replacing sedentary time with an equivalent duration of physical activity on kidney function.

METHODS

We examined the cross-sectional association of MVPA and SB with eGFR and CKD in 66,603 Japanese cohort study in 14 areas from 2004 to 2013. MVPA and SB were estimated using a self-reported questionnaire, and CKD was defined as eGFR<60 mL/min/1.73 m². Multiple linear regression analyses, logistic regression analyses, and an isotemporal substitution model were applied.

RESULTS

After adjusting for potential confounders, higher MVPA and longer SB were independently associated with higher eGFR (P_{for trend MVPA}<0.0001) and lower eGFR (P_{for trend SB}<0.0001), and a lower odds ratio (OR) of CKD (adjusted OR of MVPA≥20 MET·h/day: 0.76 [95%CI: 0.68-0.85] compared to MVPA<5 MET·h/day) and a higher OR of CKD (adjusted OR of SB≥16 h/day: 1.81 [95%CI: 1.52-2.15] compared to SB<7 h/day), respectively. The negative association between MVPA and CKD was stronger in men, and significant interactions between sex and MVPA were detected. Replacing 1 hour of SB with 1 hour of physical activity was associated with about 3 to 4% lower OR of CKD.

CONCLUSIONS

These findings indicate that replacing SB with physical activity may benefit kidney function, especially in men, adding to the possible evidence on CKD prevention.

Association between physical activity and all-cause mortality: A 15-year follow-up using a compositional data analysis

The association between the composition of movement behaviors and mortality risk, acknowledging the composition nature of daily time data, is limited explored. The aim was to investigate how the composition of time spent in sedentary behaviors (SB), light intensity physical activity (LIPA), and moderate-to-vigorous physical activity (MVPA) is associated with all-cause mortality, in a cohort with 15 years follow-up time, using compositional data analysis. Eight hundred fifty-one participants (56% women, mean age 53 years) provided objectively assessed physical activity data using an ActiGraph accelerometer and were followed for 15 years. Association of daily time composition of movement behaviors with risk of mortality was explored using compositional data analysis and hazard ratios (HR) of mortality were estimated based on a cox regression model. A significant (P < .001) positive association between time spent in SB relative to time in other behaviors and a significant (P = .018) negative association between time spent in LIPA relative to time in other behaviors, with all-cause mortality, were found. Substituting time spent in LIPA or MVPA with time in SB increased the hazard for all-cause mortality, with greater effect found for MVPA (20 minutes replacement; HR 1.26, 95% CI 1.04-1.52) than for LIPA (20 minutes replacement; HR 1.06, 95% CI 0.65-1.73). In a public health perspective, it is recommended to substitute SB with either LIPA or MVPA, but for individuals with little time spent in MVPA, the most important message may be to try to maintain that behavior.