Predictors Of Adherence To A Physical Activity Guidelines-Based Intervention In Women: A Pilot Study

PURPOSE: The ACSM recommends that all adults perform >150 min/wk moderate-to-vigorous physical activity (MVPA) for health. Yet, women are less adherent to these guidelines than men. Identifying predictors of adherence in women may provide insight on which women require additional support to meet physical activity (PA) guidelines. Thus, the objective of our study was to identify predictors of adherence to a 6-week PA guidelines-based intervention among women. METHODS: 20 sedentary women (age 53 ± 12 years; BMI 29.1 ± 6.9 kg/m2; MVPA <30 min/wk) with cardiometabolic risk factors were recruited. The intervention consisted of two supervised (~30 min/session) sessions per week, and a progressive plan for unsupervised PA to reach 150 min/wk MVPA (i.e., >40% heart rate reserve) by week 3. Adherence was monitored via a continuously worn smartwatch. Adherence was calculated as total weekly min / prescribed min and averaged across all weeks for each participant, with those >80% classified as adherent. Potential predictors were identified via baseline assessments and questionnaires prior to the start of the intervention. To identify predictors of 80% adherence, purposeful forward model selection was undertaken using the Hosmer-Lemeshow method. Risk ratios (RR) and 95% confidence intervals (CI) were produced using modified Poisson regression. RESULTS: The average adherence was 82 ± 15% and 13 (65%) women had >80% adherence. Older age (RR 1.10, 95% CI 1.02, 1.19) as well as lower emotional wellbeing (RR 0.96, 95% CI 0.92, 1.00) and higher social functioning at baseline (RAND-36; RR 1.04, 95% CI 1.00, 1.07) were significantly associated with 80% adherence. BMI as well as general health and energy/fatigue (RAND-36) were also retained in the final multivariable model as they improved model fit. CONCLUSIONS: Our pilot study shows that key demographics and metrics of quality of life may predict adherence to a PA guidelines-based intervention. Yet, larger sample sizes are needed to better elucidate demographic and behavioral predictors of exercise adherence among women so interventions can be tailored to increase their adherence to PA guidelines.