Physical Activity for Bone Health: How Much and/or How Hard?

Abstract

Purpose High-impact physical activity is associated with bone health, but higher volumes of lower-intensity activity may also be important. The aims of this study were to: 1) investigate the relative importance of volume and intensity of physical activity accumulated during late adolescence for bone health at age 23 yr; and 2) illustrate interpretation of the results. Methods This is a secondary analysis of data from the Iowa Bone Development Study, a longitudinal study of bone health from childhood through to young adulthood. The volume (average acceleration) and intensity distribution (intensity gradient) of activity at age 17, 19, 21, and 23 yr were calculated from raw acceleration ActiGraph data and averaged across ages. Hip areal bone mineral density (aBMD), total body bone mineral content (BMC), spine aBMD, and hip structural geometry (dual-energy X-ray absorptiometry, Hologic QDR4500A) were assessed at age 23 yr. Valid data, available for 220 participants (124 girls), were analyzed with multiple regression. To elucidate significant effects, we predicted bone outcomes when activity volume and intensity were high (+1SD), medium (mean), and low (−1SD). Results There were additive associations of volume and intensity with hip aBMD and total body BMC (low-intensity/low-volume cf. high-intensity/high-volume = ∆0.082 g·cm−2 and ∆169.8 g, respectively). For males only, spine aBMD intensity was associated independently of volume (low-intensity cf. high-intensity = ∆0.049 g·cm−2). For hip structural geometry, volume was associated independently of intensity (low-volume cf. high-volume = ∆4.8–6.6%). Conclusions The activity profile associated with optimal bone outcomes was high in intensity and volume. The variation in bone health across the activity volume and intensity distribution suggests intensity is key for aBMD and BMC, whereas high volumes of lower intensity activity may be beneficial for hip structural geometry.

Association Between Accelerometer-Assessed Physical Activity and Severity of COVID-19 in UK Biobank

“…A mutually adjusted model was also run for total physical activity and the intensity gradient to test whether associations were independent of the alternative activity metric consistent with previous research assessing the relative contributions of total activity and intensity of activity for health. 15,23 The variables were standardized before entry into the models and the odds ratios per cohort standard deviation reported for ease of comparison across exposures. 12 Covariates were selected on the basis of current clinical knowledge and included age (at censoring), follow-up time (difference between age at accelerometer measure and age at censoring), season of accelerometer wear, sex, ethnicity (White, South Asian, Black and African or Caribbean), Townsend score (arealevel measure of deprivation), employment status, and cardiovascular disease or cancer diagnosis before accelerometer baseline (selfreported history of heart attack, angina, stroke, or cancer variables or hospital episode with International Statistical Classification of Diseases, Tenth Revision code I20-25, I60-69, or C00-99).…”

Physical activity accumulation along the intensity spectrum differs between children and adults

“…Although considering the pattern of activity accumulation along the intensity spectrum is in its infancy (Belavý et al 2017 ; Aadland et al 2018a , b ; Rowlands et al 2018 ; Migueles et al 2021 ), the existing body of literature is encouraging in that it may identify feasible intervention targets not apparent based on more conventional analyses (Belavý et al 2017 ; Belavy et al 2018 ; Rowlands et al 2019 , 2020 ; Savikangas et al 2020 ). As an example, only relatively short bursts of intense activity are required in high-intensity interval training.…”

“…Therefore, it is conceivable that the high-intensity end of the activity intensity spectrum could be informative when aiming to maintain or develop cardiovascular fitness. Similarly, bone adaptations require only brief bursts of high-intensity activity, such as jumping, and could also be better represented if high-intensity activities were specifically targeted in numerical processing (Jämsä et al 2011 ; Rowlands et al 2020 ). These suggestions are in line with what Aadland and colleagues have reported (e.g.…”

“…Similarly, Aadland and colleagues showed that a particular intensity band (5000 to 7000 counts/minute) was more strongly associated with cardiometabolic health indicators among children than the other intensity bands (Aadland et al 2018b). Rowlands and colleagues have developed a method similarly based on fine gradation of the intensity spectrum (Rowlands et al 2018), and demonstrated that the accumulation pattern of the intensity histogram contains meaningful information related to health indicators in children (Rowlands et al 2019(Rowlands et al , 2020. However, instead of probing particular intensity bands, they represented the overall accumulation pattern by the slope of the histogram (Rowlands et al 2018).…”

“…Aadland et al 2018b , 2020 ), and Rowlands and colleagues (e.g. Rowlands et al 2018 , 2020 ), there is still a relative dearth of exploration of the finely graded activity intensity spectrum in the literature to date for children.…”