Comparing the activPAL software's Primary Time in Bed Algorithm against Self-Report and van der Berg's Algorithm

Replacing sitting with light-intensity physical activity throughout the day versus 1 bout of vigorous-intensity exercise: similar cardiometabolic health effects in multiple sclerosis. A randomised cross-over study

PURPOSE

Persons with Multiple Sclerosis (PwMS) are physically inactive and spend more time in sedentary behaviours than healthy persons, which increases the risk of developing cardiometabolic diseases. In this randomised crossover study, the cardiometabolic health effects of replacing sitting with light-intensity physical activity (LIPA) and exercise (EX) were investigated.

MATERIALS AND METHODS

Twenty-eight mildly disabled PwMS performed four 4-day activity regimens in free-living conditions; CONTROL (habitual activity), SIT, LIPA, and EX. Plasma glucose and insulin (oral glucose tolerance test), plasma lipids, inflammation, resting heart rate, blood pressure, body weight, and perceived exertion were measured (clinical-trials.gov: NCT03919058).

RESULTS

CONTROL: 9.7 h sitting/day, SIT: 13.3 h sitting/day, LIPA: 8.3 h sitting, 4.7 h standing, and 2.7 h light-intensity walking/day, and EX: 11.6 h sitting/day with 1.3 h vigorous-intensity cycling. Compared to SIT, improvements (p < 0.001) after LIPA and EX were found for insulin total area under the curve (-17 019 ± 5708 and -23 303 ± 7953 pmol/L*min), insulin sensitivity (Matsuda index +1.8 ± 0.3 and +1.9 ± 0.4) and blood lipids (triglycerides: -0.4 ± 0.1 and -0.5 ± 0.1 mmol/L; non-high-density lipoprotein cholesterol: -0.3 ± 0.1 and -0.5 ± 0.1 mmol/L), with no difference between LIPA and EX. Perceived exertion was higher after EX compared to LIPA (Borg score [6-20]: +2.6 ± 3.3, p = 0.002).

CONCLUSION

Replacing sitting with LIPA throughout the day exerts similar cardiometabolic health effects as a vigorous-intensity exercise in PwMS.IMPLICATIONS FOR REHABILITATIONIncreasing light-intensity physical activity (LIPA) throughout the day improves cardiometabolic health to the same extent as one vigorous-intensity exercise sessionIncreasing LIPA induces less exertion than performing a vigorous-intensity exercise.

Convergent validity of time in bed estimates from activPAL and Actiwatch in free-living youth and adults

Actiwatch devices are often used to estimate time in bed (TIB), but recently became commercially unavailable. Thigh-worn activPAL devices could be a viable alternative. We tested convergent validity between activPAL (CREA algorithm) and Actiwatch devices. Data were from free-living samples comprising 47 youth (3-16 valid nights/participant) and 42 adults (6-26 valid nights/participant) who wore both devices concurrently. On average, activPAL predicted earlier bedtimes and later risetimes compared to Actiwatch, resulting in longer overnight intervals (by 1.49 hours/night for youth and 0.67 hours/night for adults; both p < 0.001). TIB interruptions were predicted less commonly by activPAL (mean < 2 interruptions/night for both youth and adults) than Actiwatch (mean of 24-26 interruptions/night in both groups; both p < 0.001). Overnight intervals for both devices tended to overlap for lengthy periods (mean of 7.38 hours/night for youth and 7.69 hours/night for adults). Within these overlapping periods, the devices gave matching epoch-level TIB predictions an average of 87.9% of the time for youth and 84.3% of the time for adults. Most remaining epochs (11.8% and 15.1%, respectively) were classified as TIB by activPAL but not Actiwatch. Overall, the devices had fair agreement during the overlapping periods, but limited agreement when predicting interruptions, bedtime, or risetime. Future work should assess the criterion validity of activPAL devices to understand implications for health research. The present findings demonstrate that activPAL is not interchangeable with Actiwatch, which is consistent with their differing foundations (thigh inclination for activPAL versus wrist movement for Actiwatch).

Comparing the activPAL CREA and GHLA Algorithms for the Classification of Postures and Activity in Free-Living Children

The activPAL accelerometer has been used extensively in research to assess sedentary behaviour (SB) and physical activity (PA) outcomes. The aim of this study was to assess the comparability of PA and SB outcomes from two automated algorithms (CREA and GHLA) applied to the activPAL accelerometer. One hundred and twenty participants aged 8−12 years wore an activPAL accelerometer on their right thigh continuously for seven days on two occasions, providing valid data from 1058 days. The PALbatch software downloaded the data after applying the CREA and GHLA (latest) algorithms. The comparability of the algorithms were assessed using the mean absolute percent error (MAPE), intra-class correlation coefficients (ICC), and equivalence testing. Comparisons for daily wear time, primary lying, sitting and standing time, sedentary and stepping time, upright time, total number of steps, sit−stand transitions and stepping time ≤ 1 min revealed mainly small MAPE (≤2%), excellent ICCs (lower bound 95% CI ≥ 0.97), and equivalent outcomes. Time spent in sitting bouts > 60 min and stepping bouts > 5 min were not equivalent with the absolute zone needed to reach equivalence (≥7%). Comparable outcomes were provided for wear time and postural outcomes using the CREA or GHLA algorithms, but not for time spent in sitting bouts > 60 min and stepping bouts > 5 min.