Testing the activitystat hypothesis: a randomised controlled trial protocol

Abstract

BackgroundThe activitystat hypothesis proposes that when physical activity or energy expenditure is increased or decreased in one domain, there will be a compensatory change in another domain to maintain an overall, stable level of physical activity or energy expenditure. To date, there has been no experimental study primarily designed to test the activitystat hypothesis in adults. The aim of this trial is to determine the effect of two different imposed exercise loads on total daily energy expenditure and physical activity levels.MethodsThis study will be a randomised, multi-arm, parallel controlled trial. Insufficiently active adults (as determined by the Active Australia survey) aged 18–60 years old will be recruited for this study (n=146). Participants must also satisfy the Sports Medicine Australia Pre-Exercise Screening System and must weigh less than 150 kg. Participants will be randomly assigned to one of three groups using a computer-generated allocation sequence. Participants in the Moderate exercise group will receive an additional 150 minutes of moderate to vigorous physical activity per week for six weeks, and those in the Extensive exercise group will receive an additional 300 minutes of moderate to vigorous physical activity per week for six weeks. Exercise targets will be accumulated through both group and individual exercise sessions monitored by heart rate telemetry. Control participants will not be given any instructions regarding lifestyle. The primary outcome measures are activity energy expenditure (doubly labeled water) and physical activity (accelerometry). Secondary measures will include resting metabolic rate via indirect calorimetry, use of time, maximal oxygen consumption and several anthropometric and physiological measures. Outcome measures will be conducted at baseline (zero weeks), mid- and end-intervention (three and six weeks) with three (12 weeks) and six month (24 week) follow-up. All assessors will be blinded to group allocation.DiscussionThis protocol has been specifically designed to test the activitystat hypothesis while taking into account the key conceptual and methodological considerations of testing a biologically regulated homeostatic feedback loop. Results of this study will be an important addition to the growing literature and debate concerning the possible existence of an activitystat.Trial registrationAustralian New Zealand Clinical Trials Registry ACTRN12610000248066

Organized Sport Participation Is Associated with Higher Levels of Overall Health-Related Physical Activity in Children (CHAMPS Study-DK)

“…Although the current study results were not consistent with the activity-stat hypothesis it is possible that children participating in organized leisure-time sport differed in ways not accounted for by the study design and analysis. While current evidence on the validity of the activity-stat hypothesis is inconsistent [ 26 ], future reporting aimed at accounting for methodological limitations of previous studies may inform this debate [ 27 ].…”

The Impact of a Telehealth Intervention on Activity Profiles in Older Adults during the COVID-19 Pandemic: A Pilot Study

“…This version of the MARCA has demonstrated a very high test–retest reliability (ICC = 0.92–0.99) and high validity with accelerometry (rho = 0.72) and doubly labeled water (rho = 0.70) in adults [ 28 , 29 ]. As outlined in Table 1 , MARCA activities were hierarchically aggregated into nine super-domains with appropriate sub-domains [ 30 ]. To capture typical weekly activity patterns, the time spent in each activity domain was averaged across the two days using a 5:2 weighting for weekdays:weekend days.…”

Testing the activitystat hypothesis: a randomised controlled trial

“…The two intervention conditions involved similar types of physical activities and intensities, and differed only in volume (minutes per week). A detailed description of the exercise sessions for both conditions can be found in the published study protocol [ 32 ]. A qualified exercise physiologist conducted all group sessions and these sessions were run separately for the Moderate and Extensive groups.…”