English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Background  Public health initiatives world-wide recommend increasing physical activity (PA) to improve health. However, the dose and the intensity of PA producing the most benefit are still debated. Accurate assessment of PA is necessary in order to 1) investigate the dose–response relationship between PA and health, 2) shape the most beneficial public health initiatives and 3) test the effectiveness of such initiatives. Actigraph accelerometer is widely used to objectively assess PA, and the raw data is given in counts per unit time. Count-thresholds for low, moderate and vigorous PA are mostly based on absolute intensity. This leads to largely inadequate PA intensity assessment in a large proportion of the elderly, who due to their declining maximal oxygen uptake (VO 2max ) cannot reach the moderate/vigorous intensity as defined in absolute terms. To resolve this issue, here we report relative Actigraph intensity-thresholds for the elderly.    Methods  Submaximal-oxygen-uptake, VO 2max  and maximal heart rate (HR max ) were measured in 111 70–77 year olds, while wearing an Actigraph-GT3X+. Relationship between VO 2max  percentage (%), counts-per-minute (CPM) and gender (for both the vertical-axis (VA) and vector-magnitude (VM)) and VO 2max % and HR max % was established using a mixed-regression-model. VM-and VA-models were tested against each other to see which model predicts intensity of PA better.    Results  VO 2max  and gender significantly affected number of CPM at different PA intensities ( p  < 0.05). Therefore, intensity-thresholds were created for both men and women of ranging VO 2max  values (low, medium, high). VM-model was found to be a better predictor of PA-intensity than VA-model ( p  < 0.05). Established thresholds for moderate intensity (46−63 % of VO 2max ) ranged from 669–3367 and 834–4048 CPM and vigorous intensity (64−90 % of VO 2max ) from 1625–4868 and 2012-5423CPM, for women and men, respectively. Lastly, we used this evidence to derive a formula that predicts customized relative intensity of PA (either VO 2max % or HR max %) using counts-per-minute values as input.    Conclusion  Intensity-thresholds depend on VO 2max , gender and Actigraph-axis. PA intensity-thresholds that take all these factors into account allow for more accurate relative intensity PA assessment in the elderly and will be useful in future PA research.    Trial registration  (ClinicalTrials.gov Identifier:  NCT02017847 , registered 17. December 2013)

New relative intensity ambulatory accelerometer thresholds for elderly men and women: the Generation 100 study