Associations between 'Weekend Warrior' Physical Activity Patterns and Neurodegenerative Disease Risk

Table of Contents

Overall Summary

Overview

This study investigates whether individuals who concentrate their weekly exercise into 1-2 days, termed the 'Weekend Warrior' (WW) pattern, experience similar protection against neurodegenerative diseases (NDDs) like dementia and Parkinsonism as those who exercise regularly throughout the week. Using accelerometer data from the UK Biobank, participants were categorized based on their moderate-to-vigorous physical activity (MVPA) into WW, regular, and inactive groups. The study found that both WW and regular exercisers had significantly lower risks of developing NDDs compared to inactive individuals, suggesting that achieving the recommended amount of MVPA, regardless of its distribution, is crucial in reducing the risk of these diseases.

Key Findings

Strengths

Areas for Improvement

Significant Elements

Figure

Description: Fig. 1 details the participant selection process, showing exclusions due to data quality and missing covariates, ultimately leading to the final sample size.

Relevance: This flow diagram is crucial for understanding the data cleaning process and ensuring transparency in how the study's analytical cohort was derived.

Table

Description: Table 1 presents baseline characteristics of participants across different activity patterns and MVPA thresholds.

Relevance: This table is essential for assessing group comparability and identifying potential confounders that might affect the study's findings.

Conclusion

The findings of this study underscore the potential flexibility in achieving health benefits through physical activity, as both 'Weekend Warrior' and regular exercise patterns are associated with reduced risks of neurodegenerative diseases. This suggests that the total volume of moderate-to-vigorous physical activity is more critical than its distribution across the week. However, the study highlights areas for future research, such as the need for longer-term activity data and standardized definitions for exercise patterns. These findings offer practical insights for individuals who may struggle to maintain consistent daily exercise routines, indicating that concentrated exercise efforts can still confer significant health benefits.

Section Analysis

Abstract

Overview

This study investigated whether the "weekend warrior" (WW) approach to physical activity, where individuals concentrate their exercise into 1-2 days, offers similar protection against neurodegenerative diseases (NDDs) like dementia and Parkinsonism as regular exercise. Using accelerometer data from the UK Biobank, a large-scale health study, they categorized participants into WW, regular, and inactive groups based on their moderate to vigorous physical activity (MVPA). They found that both WW and regular exercisers had a significantly lower risk of developing NDDs compared to inactive individuals. This suggests that achieving the recommended amount of MVPA, regardless of its distribution throughout the week, may be key to lowering the risk of NDDs.

Key Aspects

Strengths

Suggestions for Improvement

Introduction

Overview

This introduction sets the stage for investigating the relationship between the "Weekend Warrior" (WW) physical activity pattern and the risk of neurodegenerative diseases (NDDs) like dementia and Parkinsonism. It begins by acknowledging the established benefits of regular moderate-to-vigorous physical activity (MVPA) for cardiovascular health, as recommended by guidelines. However, it points out that many people struggle to meet these guidelines consistently throughout the week, leading to the adoption of the WW pattern, where the recommended MVPA is concentrated into 1-2 days. The introduction then highlights the existing evidence supporting the cardiovascular benefits of the WW pattern but notes the lack of clarity regarding its impact on NDDs. This gap in knowledge forms the rationale for the study, which aims to investigate the potential association between the WW pattern and the incidence of dementia and Parkinsonism using data from the UK Biobank. The study hypothesizes that engaging in MVPA predominantly over 1-2 days a week may be associated with a decreased risk of these NDDs.

Key Aspects

Strengths

Suggestions for Improvement

Materials and Methods

Overview

This section details the study's design, data collection, processing, and analysis methods. Using data from the UK Biobank, a large-scale biomedical database and research resource, the study investigated the association between the "Weekend Warrior" (WW) physical activity pattern and the incidence of neurodegenerative diseases (NDDs) like dementia and Parkinsonism. Accelerometer data was used to objectively measure physical activity, classifying participants into WW, regular, and inactive groups based on the concentration and total amount of moderate-to-vigorous physical activity (MVPA). The study employed Cox proportional hazard models to analyze the relationship between these activity patterns and NDDs, adjusting for various demographic, socioeconomic, lifestyle, and clinical covariates. Several sensitivity analyses were conducted to assess the robustness of the findings under different assumptions and definitions.

Key Aspects

Strengths

Suggestions for Improvement

Results

Overview

This section presents the findings of the study, which investigated the association between the "weekend warrior" (WW) physical activity pattern and the risk of developing dementia and Parkinsonism. The study analyzed data from 92,784 participants in the UK Biobank. Participants were categorized into WW, regular, and inactive groups based on their weekly moderate-to-vigorous physical activity (MVPA). The results showed that both WW and regular exercisers had a significantly lower risk of developing both dementia and Parkinsonism compared to inactive individuals. Several sensitivity analyses were conducted to test the robustness of the findings under different MVPA thresholds and WW definitions, and the results largely remained consistent, supporting the protective effect of the WW pattern against neurodegenerative diseases.

Key Aspects

Strengths

Suggestions for Improvement

Non-Text Elements

Fig. 1. Flow diagram of participants.
First Reference in Text
A total of 92,784 participants were finally enrolled in this study (mean [SD] age, 61.88 [7.87] years; 40,474 [43.62%] men; 52, 310 [56.38%] women) (Fig. 1).
Description
  • Overall structure: The diagram starts with the initial pool of participants who wore the accelerometer (N=103,662). It then depicts the exclusions made at various stages, including those with insufficient accelerometer data quality, missing covariates, and those diagnosed with dementia or Parkinsonism prior to or within two years of enrollment. The final sample sizes for the analysis of all-cause dementia (N=92,144) and all-cause Parkinsonism (N=92,048) are clearly indicated at the end of the flow.
  • Visual representation of participant selection: The flow diagram visually represents the process of participant selection for the study. It shows the initial number of participants and how this number decreases at each stage due to specific exclusion criteria. Each step in the process is represented by a box, with arrows connecting the boxes to show the flow of participants.
  • Exclusion criteria: Specific exclusion criteria are listed in the diagram, including insufficient accelerometer data quality (e.g., monitor not sufficiently calibrated, unrealistically high acceleration values), missing covariates (age, sex, ethnicity, etc.), and prior diagnosis of dementia or Parkinsonism.
  • Number of participants excluded at each stage: The diagram clearly indicates the number of participants excluded at each stage. For example, it shows that 9,187 participants were excluded due to invalid wear time, 1,630 due to missing covariates, and 640 and 736 due to prior or early diagnosis of dementia and Parkinsonism, respectively.
Scientific Validity
  • Transparency and reproducibility: The flow diagram clearly outlines the participant selection process, which is crucial for the transparency and reproducibility of the study. The explicit statement of exclusion criteria and the number of participants excluded at each step allows readers to understand how the final sample was derived and assess potential biases introduced by the selection process.
  • Justification of exclusion criteria: The exclusion of participants with insufficient accelerometer data quality is a valid step to ensure the reliability of the physical activity measurements. Similarly, excluding individuals with missing covariates helps to avoid biases related to these variables. Excluding participants with prior or early diagnosis of the outcome is essential to assess the association between physical activity patterns and incident NDDs, rather than the influence of pre-existing conditions.
  • Missing data handling: While the diagram mentions 'Missing covariates,' it would strengthen the scientific rigor to specify the exact covariates that were missing. This would enhance transparency and allow for a more thorough assessment of potential biases due to missing data.
  • Data cleaning and preparation: The flow diagram provides a clear visual representation of the data cleaning and preparation steps, which are essential for ensuring the validity of the subsequent analyses. This contributes to the overall rigor of the study.
Communication
  • Clarity and organization: The flow diagram is generally clear and easy to follow, effectively communicating the process of participant selection and the resulting sample sizes for the study. The use of clear labels and distinct categories makes it easy to understand the reasons for exclusion at each stage. The visual representation helps to quickly grasp the overall participant selection process.
  • Completeness of information: The diagram could be improved by including the specific reasons for missing covariates. While the diagram mentions 'Missing covariates,' it doesn't detail what these covariates are. Providing this information directly in the diagram or in the caption would enhance transparency and allow readers to fully understand the reasons for exclusion.
  • Visual representation: The diagram effectively uses visual cues, such as different shapes and colors, to distinguish between different stages of the participant selection process. This enhances readability and makes it easier to follow the flow of information.
Fig. 2. Associations Between WW pattern (≥150 or ≥300 min/wk with ≥50% over 1-2...
Full Caption

Fig. 2. Associations Between WW pattern (≥150 or ≥300 min/wk with ≥50% over 1-2 days) and Incidence of Dementia and Parkinsonism over 1-2 Days, Adjusted for Multiple Variables.

First Reference in Text
After adjusting for sociodemographic, lifestyle covariates, and comorbidities, the WW pattern, when achieving 50% of the guideline-recommended activity (≥150 min or ≥300 min) over 1-2 days, was associated with a lower risk of dementia (≥150 min: HR 0.68, 95% CI 0.56-0.84; ≥300 min: HR 0.65, 95% CI 0.50-0.85) and Parkinsonism (≥150 min: HR 0.47, 95% CI 0.35-0.63; ≥300 min: HR 0.58, 95% CI 0.41-0.82) (Fig. 2A and B).
Description
  • Overall purpose: Figure 2 presents the results of a Cox proportional hazards model analysis, examining the association between different physical activity patterns (Weekend Warrior, Regular, Inactive) and the incidence of two neurodegenerative diseases: dementia and Parkinsonism. The analysis is stratified by two different weekly Moderate-to-Vigorous Physical Activity (MVPA) thresholds: ≥150 minutes and ≥300 minutes. A 'Weekend Warrior' is defined as someone who achieves at least 50% of their weekly MVPA in 1-2 days.
  • Structure and content: The figure includes two panels (A and B), one for each MVPA threshold (≥150 min/week and ≥300 min/week, respectively). Each panel contains two forest plots, one for dementia and one for Parkinsonism. Each forest plot displays the hazard ratio (HR) and 95% confidence interval (CI) for the Regular and WW groups compared to the Inactive group (reference group).
  • Interpretation of forest plots: A forest plot is a graphical representation of the results of a meta-analysis or, in this case, a Cox proportional hazards model. Each horizontal line represents a comparison between two groups (e.g., Regular vs. Inactive). The square on the line represents the point estimate of the hazard ratio (HR), and the horizontal line extending from the square represents the 95% confidence interval (CI). An HR less than 1 indicates a lower risk in the exposed group compared to the reference group.
Scientific Validity
  • Appropriate statistical analysis: The use of Cox proportional hazards models is appropriate for analyzing time-to-event data, such as the incidence of dementia and Parkinsonism. Adjusting for relevant covariates is crucial to control for potential confounding and isolate the effect of physical activity patterns.
  • Clear definition of variables: The study clearly defines the exposure variable (Weekend Warrior physical activity pattern) and the outcome variables (dementia and Parkinsonism). The use of pre-defined MVPA thresholds and the 50% criterion for defining the WW pattern adds clarity and rigor to the analysis.
  • Addressing reverse causality: The study acknowledges the potential for reverse causality, which is a common concern in observational studies. While excluding individuals with early diagnoses is a good step, it doesn't completely eliminate the possibility that undiagnosed or preclinical disease may influence physical activity levels. This limitation should be discussed further.
  • Presentation of results: The figure presents the results with appropriate measures of effect (hazard ratios) and uncertainty (95% confidence intervals). This allows readers to assess the statistical significance and magnitude of the associations.
Communication
  • Use of appropriate visualization: The figure uses forest plots, a standard way to visually represent the results of a Cox proportional hazards model. The inclusion of hazard ratios and confidence intervals allows for a clear comparison of the risk between different physical activity patterns. The layout is generally clear, with separate panels for different MVPA thresholds.
  • Transparency of adjusted variables: While the caption mentions adjustment for multiple variables, listing these variables directly in the figure or caption would improve transparency. Knowing the specific covariates included in the model is important for interpreting the results.
  • Clarity of main message: The figure effectively communicates the main finding that the WW pattern is associated with a lower risk of both dementia and Parkinsonism compared to the inactive group. This message is clearly conveyed by the hazard ratios and confidence intervals presented in the forest plots.
  • Accessibility of visual elements: The use of color to differentiate between outcome events (dementia and Parkinsonism) is helpful. However, consider using different shapes or patterns for the data points in addition to color to enhance accessibility for readers with color vision deficiencies.
Fig. 3. Associations Between WW pattern (≥150 or ≥300 min/wk with ≥75% over 1-2...
Full Caption

Fig. 3. Associations Between WW pattern (≥150 or ≥300 min/wk with ≥75% over 1-2 days) and Incidence of Dementia and Parkinsonism Over 1-2 Days, Adjusted for Multiple Variables.

First Reference in Text
In multivariable-adjusted models, the WW pattern persistently showed a lower risk for dementia (≥150 min: HR 0.61, 95% CI 0.41-0.91; ≥300 min: HR 0.34, 95% CI 0.14-0.82) and Parkinsonism (≥150 min: HR 0.22, 95% CI 0.10-0.47; ≥300 min: HR 0.20, 95% CI 0.05-0.80) (Fig. 3A and B).
Description
  • Overall purpose and comparison with Figure 2: This figure, similar in structure to Figure 2, explores the relationship between the 'Weekend Warrior' (WW) physical activity pattern and the risk of dementia and Parkinsonism. However, it uses a more stringent definition of the WW pattern: individuals who complete at least 75% of their total weekly Moderate-to-Vigorous Physical Activity (MVPA) within 1-2 days. The analysis is again stratified by two weekly MVPA thresholds (≥150 minutes and ≥300 minutes).
  • Structure and content: The figure comprises two panels (A and B), corresponding to the two MVPA thresholds. Each panel presents two forest plots, one for dementia and one for Parkinsonism. The forest plots display hazard ratios (HR) and 95% confidence intervals (CI) for the Regular and WW groups compared to the Inactive group, which serves as the reference.
  • Interpretation of hazard ratios and confidence intervals: The hazard ratio (HR) quantifies the relative risk of the outcome in the exposed group (Regular or WW) compared to the reference group (Inactive). An HR less than 1 suggests a reduced risk, while an HR greater than 1 indicates an increased risk. The 95% confidence interval (CI) provides a range of plausible values for the true HR.
Scientific Validity
  • Dose-response analysis: The use of a more stringent definition for the WW pattern (75% of MVPA in 1-2 days) allows for investigating the dose-response relationship between the concentration of physical activity and the risk of NDDs. This adds valuable information to the findings presented in Figure 2.
  • Methodological rigor: The consistent use of Cox proportional hazards models and adjustment for multiple variables ensures methodological consistency and helps to control for confounding factors.
  • Statistical power and precision: The small number of events in some groups, particularly for the WW pattern at the 300 min/week threshold, may limit the statistical power and precision of the estimates. This should be acknowledged and discussed as a potential limitation.
  • Causality and confounding: While the results suggest a strong protective effect of the WW pattern, especially for Parkinsonism, it's important to consider the potential for residual confounding and the limitations of observational studies in establishing causal relationships.
Communication
  • Visual consistency and clarity: The consistent use of forest plots maintains visual clarity and allows for direct comparison with Figure 2. The clear labeling of axes, groups, and effect estimates (HR and 95% CI) facilitates easy interpretation of the results.
  • Effective communication of key findings: The figure effectively highlights the key finding that increasing the proportion of MVPA performed in a WW pattern to 75% strengthens the observed associations, particularly for Parkinsonism. This is clearly demonstrated by the smaller hazard ratios and narrower confidence intervals.
  • Transparency of adjusted variables: Similar to Figure 2, explicitly listing the adjusted covariates in the figure or caption would enhance transparency and allow readers to fully understand the model.
Table 1. Characteristics of participants by the different thresholds of MVPA...
Full Caption

Table 1. Characteristics of participants by the different thresholds of MVPA per week.

First Reference in Text
The baseline characteristics of all participants stratified by different patterns were shown in Table 1.
Description
  • Overall purpose: Table 1 presents the baseline characteristics of the study participants, stratified by their physical activity patterns (Inactive, Regular, and Weekend Warrior - WW) and two different weekly Moderate-to-Vigorous Physical Activity (MVPA) thresholds: ≥150 minutes and ≥300 minutes. The WW pattern is defined as achieving at least 50% of the weekly MVPA in one or two days.
  • Structure and content: The table is organized into several sections: demographic and socioeconomic characteristics (age, sex, ethnicity, education, employment), lifestyle characteristics (diet, smoking, alcohol consumption), and clinical, medication, and medical history (blood pressure, BMI, prevalence of hypertension, diabetes, and cardiovascular disease).
  • Data presentation format: For continuous variables, the table presents the median and interquartile range (IQR). The IQR represents the range between the 25th and 75th percentiles of the data distribution and is a measure of statistical dispersion. For categorical variables, the table shows the number (n) and percentage (%) of participants in each category.
  • Definition of MVPA: MVPA refers to physical activity that is performed at an intensity equal to or greater than walking briskly. It is a key component of physical activity guidelines and is associated with various health benefits.
Scientific Validity
  • Importance of baseline characteristics: Presenting baseline characteristics is crucial in observational studies to assess the comparability of different groups (Inactive, Regular, WW) and identify potential confounding factors. This information is essential for interpreting the results of the subsequent analyses.
  • Relevance of variables: The choice of variables presented in the table is generally appropriate, covering key demographic, socioeconomic, lifestyle, and clinical factors that could influence the relationship between physical activity and NDD risk.
  • Appropriate descriptive statistics: The use of median and IQR for continuous variables is appropriate given the likely skewed distribution of some of these variables (e.g., MVPA, sedentary time). Presenting both raw numbers and percentages for categorical variables enhances transparency.
  • Statistical significance testing: The table could be improved by including a measure of statistical significance for the differences in baseline characteristics between groups (e.g., p-values from chi-squared tests or ANOVA). This would help readers assess the statistical significance of the observed differences.
Communication
  • Clarity and organization: The table is well-organized, presenting the characteristics for each group (Inactive, Regular, WW) side-by-side, which facilitates comparison. The use of clear headings and labels makes it easy to understand the information presented.
  • Data presentation: Providing the number (N) for each group is helpful for understanding the sample size and distribution across different physical activity patterns. Including both percentages and raw numbers for categorical variables enhances transparency and allows readers to fully grasp the data distribution.
  • Completeness of information: While the table presents a comprehensive set of baseline characteristics, consider adding information on other relevant factors, such as physical activity levels prior to the study period, if available. This could provide additional context for interpreting the results.
Table 2. Associations between physical activity pattern and incident of outcome...
Full Caption

Table 2. Associations between physical activity pattern and incident of outcome across varying WW definition.

First Reference in Text
In models adjusted for multiple variables and stratified by MVPA quartiles, the WW pattern, characterized by exceeding MVPA percentiles of 25th, 50th, and 75th and completing 50% or 75% of the total exercise within 1-2 days, consistently demonstrated a lower risk for both dementia (≥115.2 min: HR 0.66, 95% CI 0.54-0.81; ≥230.4 min: HR 0.72, 95% CI 0.58-0.90; ≥403.2 min: HR 0.67, 95% CI 0.47-0.95) and Parkinsonism (≥115.2 min: HR 0.48, 95% CI 0.37-0.64; ≥230.4 min: HR 0.58, 95% CI 0.43-0.79; ≥403.2 min: HR 0.55, 95% CI 0.34-0.87) (Table 2).
Description
  • Overall purpose: Table 2 presents the results of Cox proportional hazards models examining the association between different Weekend Warrior (WW) physical activity patterns and the incidence of dementia and Parkinsonism. The table explores various definitions of the WW pattern, based on different MVPA thresholds (25th, 50th, and 75th percentiles) and the proportion of MVPA completed within 1-2 days (50% or 75%).
  • Structure and content: The table is organized by outcome (all-cause dementia and all-cause Parkinsonism) and then by WW definition. Each row represents a different analysis, with the WW definition specified in the first column. The remaining columns present the number of events, the number of participants, and the hazard ratio (HR) with its 95% confidence interval (CI) for each group (Inactive, Regular, WW).
  • MVPA thresholds and percentiles: MVPA refers to moderate-to-vigorous physical activity, which is activity performed at an intensity equal to or greater than brisk walking. The different percentile thresholds represent different levels of MVPA, with higher percentiles indicating greater amounts of MVPA.
  • Interpretation of hazard ratio and confidence interval: The hazard ratio (HR) is a measure of the relative risk of the outcome in the exposed group (e.g., WW) compared to the reference group (Inactive). An HR less than 1 indicates a lower risk in the exposed group. The 95% confidence interval (CI) provides a range of plausible values for the true HR.
Scientific Validity
  • Sensitivity analysis with varying WW definitions: Exploring different definitions of the WW pattern is a strength of this analysis, as it allows for assessing the robustness of the findings across different thresholds and criteria. This helps to address the lack of a standardized definition of the WW pattern.
  • Use of MVPA quartiles: The use of MVPA quartiles as thresholds provides a data-driven approach to defining different levels of physical activity. This is a more robust approach compared to using arbitrary thresholds.
  • Methodological consistency: The consistent use of Cox proportional hazards models and adjustment for multiple variables ensures methodological rigor and helps to control for confounding factors.
  • Statistical power: The small number of events in some groups, especially for the more stringent WW definitions, may limit the statistical power of these analyses. This should be acknowledged and discussed as a potential limitation.
Communication
  • Clarity and organization: The table is clearly structured, presenting the results for different WW definitions and MVPA thresholds in a systematic way. The use of consistent labels and abbreviations makes it easy to follow the different analyses.
  • Data presentation: Presenting the number of events and participants for each analysis is essential for transparency and allows readers to assess the underlying data. Including both hazard ratios and confidence intervals provides a clear measure of effect and uncertainty.
  • Comparison with regular exercisers: While the table focuses on the WW pattern, consider adding a separate column for the regular exercisers group for each analysis. This would allow for a direct comparison between the two active groups and provide a more complete picture of the relationship between physical activity and NDD risk.

Discussion

Overview

This Discussion section summarizes the study's main finding: concentrating the recommended amount of moderate-to-vigorous physical activity (MVPA) into 1-2 days a week (the Weekend Warrior or WW pattern) is associated with a lower risk of dementia and Parkinsonism, similar to the benefit seen with regular exercise. The authors connect this finding to existing research showing similar benefits of the WW pattern for other health outcomes, like cardiovascular health. They also discuss the study's limitations, such as relying on a single week of accelerometer data and the lack of a standardized WW definition, and suggest directions for future research, including longer-term activity monitoring and the development of a standardized WW definition.

Key Aspects

Strengths

Suggestions for Improvement

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