Testing the activitystat hypothesis: a randomised controlled trial

Gomersall, S. R., Maher, C., English, C., Rowlands, A. V., Dollman, J., Norton, K. and Olds, T. (2016) Testing the activitystat hypothesis: a randomised controlled trial. BMC Public Health, 16 1: 900. doi:10.1186/s12889-016-3568-x


Author Gomersall, S. R.
Maher, C.
English, C.
Rowlands, A. V.
Dollman, J.
Norton, K.
Olds, T.
Title Testing the activitystat hypothesis: a randomised controlled trial
Journal name BMC Public Health   Check publisher's open access policy
ISSN 1471-2458
Publication date 2016-08-30
Sub-type Article (original research)
DOI 10.1186/s12889-016-3568-x
Open Access Status DOI
Volume 16
Issue 1
Start page 900
Total pages 14
Place of publication London, United Kingdom
Publisher BioMed Central
Language eng
Abstract It has been hypothesised that an 'activitystat' may biologically regulate energy expenditure or physical activity levels, thereby limiting the effectiveness of physical activity interventions. Using a randomised controlled trial design, the aim of this study was to investigate the effect of a six-week exercise stimulus on energy expenditure and physical activity, in order to empirically test this hypothesis.

Previously inactive adults (n = 129) [age (mean ± SD) 41 ± 11 year; body mass index 26.1 ± 5.2 kg/m(2)] were randomly allocated to a Control group (n = 43) or a 6-week Moderate (150 min/week) (n = 43) or Extensive (300 min/week) (n = 43) exercise intervention group. Energy expenditure and physical activity were measured using a combination of accelerometry (total counts, minutes spent in moderate to vigorous physical activity) and detailed time use recalls using the Multimedia Activity Recall for Children and Adults (total daily energy expenditure, minutes spent in moderate to vigorous physical activity) at baseline, mid- and end-intervention and 3- and 6-month follow up. Resting metabolic rate was measured at baseline and end-intervention using indirect calorimetry. Analysis was conducted using random effects mixed modeling.

At end-intervention, there were statistically significant increases in all energy expenditure and physical activity variables according to both accelerometry and time use recalls (p < 0.001) in the Moderate and Extensive groups, relative to Controls. There was no significant change in resting metabolic rate (p = 0.78).

Taken together, these results show no evidence of an "activitystat" effect. In the current study, imposed exercise stimuli of 150-300 min/week resulted in commensurate increases in overall energy expenditure and physical activity, with no sign of compensation in either of these constructs.

ACTRN12610000248066  (registered prospectively 24 March 2010).
Formatted abstract
Background: It has been hypothesised that an 'activitystat' may biologically regulate energy expenditure or physical activity levels, thereby limiting the effectiveness of physical activity interventions. Using a randomised controlled trial design, the aim of this study was to investigate the effect of a six-week exercise stimulus on energy expenditure and physical activity, in order to empirically test this hypothesis.

Methods: Previously inactive adults (n = 129) [age (mean ± SD) 41 ± 11 year; body mass index 26.1 ± 5.2 kg/m2] were randomly allocated to a Control group (n = 43) or a 6-week Moderate (150 min/week) (n = 43) or Extensive (300 min/week) (n = 43) exercise intervention group. Energy expenditure and physical activity were measured using a combination of accelerometry (total counts, minutes spent in moderate to vigorous physical activity) and detailed time use recalls using the Multimedia Activity Recall for Children and Adults (total daily energy expenditure, minutes spent in moderate to vigorous physical activity) at baseline, mid- and end-intervention and 3- and 6-month follow up. Resting metabolic rate was measured at baseline and end-intervention using indirect calorimetry. Analysis was conducted using random effects mixed modeling.

Results: At end-intervention, there were statistically significant increases in all energy expenditure and physical activity variables according to both accelerometry and time use recalls (p < 0.001) in the Moderate and Extensive groups, relative to Controls. There was no significant change in resting metabolic rate (p = 0.78).

Conclusion: Taken together, these results show no evidence of an "activitystat" effect. In the current study, imposed exercise stimuli of 150-300 min/week resulted in commensurate increases in overall energy expenditure and physical activity, with no sign of compensation in either of these constructs.

Trial registration number: ACTRN12610000248066 (registered prospectively 24 March 2010)
Keyword Accelerometry
Compensation
Energy expenditure
Physical activity
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
School of Human Movement and Nutrition Sciences Publications
 
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