Accelerometer-Derived “Weekend Warrior” Physical Activity and Incident Cardiovascular Disease

Key Points

Question  Does engagement in moderate to vigorous physical activity, with most activity concentrated within 1 to 2 days of the week (ie, a “weekend warrior” pattern), confer similar cardiovascular benefits to more evenly distributed physical activity?

Findings  In an analysis of 89 573 individuals providing a week of accelerometer-based physical activity data, a weekend warrior pattern of physical activity was associated with similarly lower risks of incident atrial fibrillation, myocardial infarction, heart failure, and stroke compared with more evenly distributed physical activity.

Meaning  Increased activity, even when concentrated within 1 to 2 days each week, may be effective for improving cardiovascular risk profiles.

Importance  Guidelines recommend 150 minutes or more of moderate to vigorous physical activity (MVPA) per week for overall health benefit, but the relative effects of concentrated vs more evenly distributed activity are unclear.

Objective  To examine associations between an accelerometer-derived “weekend warrior” pattern (ie, most MVPA achieved over 1-2 days) vs MVPA spread more evenly with risk of incident cardiovascular events.

Design, Setting, and Participants  Retrospective analysis of UK Biobank cohort study participants providing a full week of accelerometer-based physical activity data between June 8, 2013, and December 30, 2015.

Exposures  Three MVPA patterns were compared: active weekend warrior (active WW, ≥150 minutes with ≥50% of total MVPA achieved in 1-2 days), active regular (≥150 minutes and not meeting active WW status), and inactive (<150 minutes). The same patterns were assessed using the sample median threshold of 230.4 minutes or more of MVPA per week.

Main Outcomes and Measures  Associations between activity pattern and incident atrial fibrillation, myocardial infarction, heart failure, and stroke were assessed using Cox proportional hazards regression, adjusted for age, sex, racial and ethnic background, tobacco use, alcohol intake, Townsend Deprivation Index, employment status, self-reported health, and diet quality.

Results  A total of 89 573 individuals (mean [SD] age, 62 [7.8] years; 56% women) who underwent accelerometry were included. When stratified at the threshold of 150 minutes or more of MVPA per week, a total of 37 872 were in the active WW group (42.2%), 21 473 were in the active regular group (24.0%), and 30 228 were in the inactive group (33.7%). In multivariable-adjusted models, both activity patterns were associated with similarly lower risks of incident atrial fibrillation (active WW: hazard ratio [HR], 0.78 [95% CI, 0.74-0.83]; active regular: 0.81 [95% CI, 0.74-0.88; inactive: HR, 1.00 [95% CI, 0.94-1.07]), myocardial infarction (active WW: 0.73 [95% CI, 0.67-0.80]; active regular: 0.65 [95% CI, 0.57-0.74]; and inactive: 1.00 [95% CI, 0.91-1.10]), heart failure (active WW: 0.62 [95% CI, 0.56-0.68]; active regular: 0.64 [95% CI, 0.56-0.73]; and inactive: 1.00 [95% CI, 0.92-1.09]), and stroke (active WW: 0.79 [95% CI, 0.71-0.88]; active regular: 0.83 [95% CI, 0.72-0.97]; and inactive: 1.00 [95% CI, 0.90-1.11]). Findings were consistent at the median threshold of 230.4 minutes or more of MVPA per week, although associations with stroke were no longer significant (active WW: 0.89 [95% CI, 0.79-1.02]; active regular: 0.87 [95% CI, 0.74-1.02]; and inactive: 1.00 [95% CI, 0.90-1.11]).

Conclusions and Relevance  Physical activity concentrated within 1 to 2 days was associated with similarly lower risk of cardiovascular outcomes to more evenly distributed activity.

Physical activity is regarded as favorable for health and is consistently associated with lower risks of death and cardiovascular disease.¹ World Health Organization and American Heart Association guidelines recommend 150 minutes or more of moderate to vigorous physical activity (MVPA) per week, without specifying an optimal MVPA pattern.^1,2 The UK National Health Service recommends MVPA be spread “evenly over 4-5 days per week, or every day.”³ However, it remains unclear whether MVPA concentrated within 1 to 2 days per week (“weekend warrior” pattern⁴) confers similar benefits compared with more evenly distributed activity. Prior studies were limited by self-reported activity,⁴ modest sample sizes,⁵ and a limited set of outcomes (eg, mortality).^4,5

Here, associations between physical activity patterns, defined using wrist-based accelerometers, and incident cardiovascular events were assessed among nearly 90 000 participants of the UK Biobank prospective cohort study.

The UK Biobank is a prospective cohort of 502 629 participants enrolled between 2006 and 2010.⁶ Briefly, 9.2 million individuals aged 40 to 69 years living within 25 miles of 22 assessment centers in the UK were invited, and 5.4% participated in the baseline assessment (Table). Information on race and ethnicity were included given prior associations with physical activity and cardiovascular events and was determined by self-report based on fixed categories.

Within the accelerometer substudy, 103 695 participants submitted data from an Axivity AX3 wrist-based triaxial accelerometer worn for 1 week.⁷ The sensor captured continuous acceleration at 100 Hz with dynamic range ±8g. As described previously, acceleration signals were calibrated to gravity.⁷ Sample data were combined into 5-second epochs, each representing mean vector magnitude. Non–wear time was identified as consecutive stationary episodes of 60 minutes or more in which all 3 axes had an SD less than 13.0 mg.⁷ Epochs representing non–wear time were imputed based on the mean of similar time-of-day vector magnitude and intensity distribution data points on different days. We excluded individuals whose wear time was insufficient to support imputation (no wear data in each 1-hour period of the 24-hour cycle), whose signals were insufficient for calibration or MVPA estimation, and whose mean acceleration values were nonphysiologic (eFigure 1 in Supplement 1).⁸

MVPA was then classified using a published machine-learning–based method developed to classify a broad range of activities (eg, walking, jogging, stationary cycling, elliptical, and others) and validated in a UK-based sample.⁸ Because optimal MVPA levels using wrist-based accelerometers are unclear,⁹ we assessed multiple thresholds. For our primary analyses, we assessed the guideline-based threshold (≥150 minutes/week^1-3) and the sample median (≥230.4 minutes) based on UK national health surveys reporting approximately half of individuals are physically active.¹⁰ We tested additional thresholds in secondary analyses. Quiz Ref IDIndividuals were classified as active weekend warrior (active WW, at or above the MVPA threshold and ≥50% of total MVPA over 1-2 days⁴), active regular (at or above MVPA threshold but not active WW), and inactive (below MVPA threshold).

We assessed associations between activity pattern and incident atrial fibrillation (AF), myocardial infarction (MI), heart failure (HF), and stroke using Cox proportional hazards models adjusted for age, sex, racial and ethnic background, tobacco use, Townsend Deprivation Index, alcohol intake, educational attainment, employment status, self-reported health, and diet quality. We used a complete case analysis (eFigure 1 in Supplement 1). To compare activity patterns without thresholding, we fit analogous models comparing active WW vs regular patterns with MVPA decile as a stratification variable. Exposure and outcome definitions are described in eTables 1 and 2 in Supplement 1. We plotted the Kaplan-Meier cumulative incidence of each outcome stratified by activity pattern and calculated E-values. We performed multiple secondary analyses (eMethods in Supplement 1).

Participants provided written informed consent. The UK Biobank was approved by the UK Biobank Research Ethics Committee (reference No. 11/NW/0382). UK Biobank data were used under application 17488. Analyses were performed using R version 4.0.¹¹ Hazard ratios and 95% CIs are presented using floating absolute risks.¹²

Our analyses included 89 573 individuals who underwent activity measurement between June 8, 2013, and December 30, 2015 (Table; eTables 3 and 4 and eFigure 1 in Supplement 1). The median follow-up time was 6.3 years (quartile 1: 5.7, quartile 3: 6.8). Stratified at the guideline-based threshold of 150 minutes or more of MVPA per week, a total of 37 872 participants were in the active WW group (42.2%), 21 473 were in the active regular group (24.0%), and 30 228 were in the inactive group (33.7%). Individuals in the active WW group had substantially more MVPA on their 2 most active days vs the remaining 5 days, while those in the active regular group had more consistent MVPA (Figure 1; eFigure 2 in Supplement 1).

Quiz Ref IDIn multivariable-adjusted models, both activity patterns were associated with similarly lower risks of incident AF, MI, and HF at both the guideline-based (≥150 minutes) and median (≥230.4 minutes) thresholds (Figure 2). Stroke associations were also similar, although significant only at the guideline-based threshold (Figure 2). Event rates were comparable between the active WW and active regular groups (eFigures 3 and 4 in Supplement 1). In multivariable models stratified by MVPA decile, there were no differences in risk with the WW pattern (AF: hazard ratio [HR], 0.98 [95% CI, 0.89-1.09]; MI: HR, 1.12 [95% CI, 0.95-1.30]; HF: HR, 0.92 [95% CI, 0.79-1.08]; stroke: HR, 0.92 [95% CI, 0.77-1.11]). Findings were generally consistent across other activity thresholds (Figure 2; eTable 5 in Supplement 1), alternative WW definitions (eTables 6 and 7 and eFigure 5 in Supplement 1), a 2-year blanking period (eTable 8 in Supplement 1), additional covariate adjustment (eTable 9 in Supplement 1), individuals with incomplete accelerometer data included as inactive (eTable 10 in Supplement 1), and excluding imputed wear time (eTable 11 in Supplement 1). Both activity patterns were associated with similarly lower risks of incident musculoskeletal conditions (eTable 12 and eFigure 6 in Supplement 1).

These study results have implications for efforts leveraging physical activity to reduce cardiovascular morbidity. First, when quantified using accelerometry, a weekend warrior pattern appears common. Across multiple activity thresholds, more than half of active individuals accrued most of their MVPA in 1 to 2 days. Second, varying activity patterns were observed, in only 5 years’ time, to have similar associations with lower risk of AF, MI, HF, and stroke. These observations thereby extend prior work reporting improved cardiovascular outcomes with increasing moderate and vigorous activity,^8,13,14 as well as reports suggesting that concentrated physical activity is associated with similar reductions in mortality to more regular activity.^4,5Quiz Ref ID Specifically, these findings suggest that engagement in physical activity, regardless of pattern, may optimize risk across a broad spectrum of cardiovascular diseases. Third, efforts to increase physical activity for cardiovascular health may be effective even when such efforts are concentrated into 1 to 2 days per week. Because weekend warrior patterns may be more feasible for certain schedules, targeted interventions delivered over shorter timeframes may be more accessible. Despite concern that weekend warrior activity may be associated with musculoskeletal injury,¹⁵ similarly lower risk of musculoskeletal conditions with both activity patterns was observed. Future research is warranted to better define potential negative effects of concentrated activity.

This study had some limitations. First, activity was measured over 1 week, and individuals may have modified their behavior during observation. Second, a validated MVPA classification method developed using a broad range of activities (eg, walking, jogging, stationary cycling, elliptical, and others) was used,⁸ but MVPA classification accuracy may vary by activity type. Third, optimal MVPA thresholds using wrist-based accelerometers remain unclear.⁹ However, findings were consistent across multiple thresholds, including the 25th percentile or 115.2 minutes or more (ie, below guideline recommendations^1-3). Fourth, analysis of a single UK-based sample comprising predominantly White individuals may limit generalizability. Fifth, most covariates were ascertained several years prior to accelerometry and are subject to misclassification. Sixth, the weekend warrior pattern is less well-defined using accelerometers, but findings were consistent across multiple definitions.

Within nearly 90 000 individuals providing wrist-based activity quantification, physical activity concentrated within 1 to 2 days was associated with similarly lower risk of cardiovascular outcomes to more regular activity. Future prospective studies are warranted to assess whether interventions to increase physical activity, even when concentrated within a day or 2 each week, improve cardiovascular outcomes.

Accepted for Publication: June 2, 2023.

Corresponding Author: Patrick T. Ellinor, MD, PhD, Cardiac Arrhythmia Service and Cardiovascular Research Center, Massachusetts General Hospital, 55 Fruit St, GRB 109, Boston, MA 02114 (ellinor@mgh.harvard.edu).

Author Contributions: Dr Khurshid had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Khurshid.

Acquisition, analysis, or interpretation of data: All authors.

Drafting of the manuscript: Khurshid, Guseh, Ellinor.

Critical revision of the manuscript for important intellectual content: Al-Alusi, Churchill, Guseh, Ellinor.

Statistical analysis: Khurshid.

Obtained funding: Ellinor.

Administrative, technical, or material support: Ellinor.

Supervision: Guseh, Ellinor.

Conflict of Interest Disclosures: Dr Al-Alusi has received grants from the National Institutes of Health (NIH) (T32-HL007208). Dr Churchill reported receiving grants from the NIH. Dr Guseh reported receiving grants from the American Heart Association (19AMFDP34990046) and the President and Fellows of Harvard College (5KL2 TR002542-04). Dr Ellinor reported receiving grants from the NIH (1RO1HL092577, 1R01HL157635, and 5R01HL139731), the American Heart Association Strategically Focused Research Networks (18SFRN34110082), the European Union (MAESTRIA 965286), Bayer AG (to the Broad Institute), IBM Health (to the Broad Institute), Bristol Myers Squibb (to Massachusetts General Hospital), and Pfizer (to Massachusetts General Hospital) and personal fees from Bayer AG, Novartis, and MyoKardia. No other disclosures were reported.

Data Sharing Statement: See Supplement 2.