Executive Summary

• Mental health is a critical component of overall well-being, with depression, anxiety, and stress being the most prevalent concerns globally

• The American College of Sports Medicine (ACSM) recommends a minimum of 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity exercise per week, with evidence suggesting that step counts exceeding 5,000 per day are associated with improved mental health

• This study examines the relationship between daily step counts, measured via the Sahha app, and mental health levels assessed by the Depression, Anxiety, and Stress Scales-21 (DASS-21)

• Depression: Each additional 1,000 steps per day was associated with a statistically significant decrease of 0.5631 points on the depression scale (p = 0.006). Age also had a significant negative association with depression scores (p = 0.041), while gender was not a significant predictor.

• Anxiety: Each additional 1,000 steps per day was associated with a 0.2750-point reduction in anxiety scores (p = 0.030). Age was also a significant predictor (p = 0.001), whereas gender was not significant.

• Stress: A 1,000-step increase was linked to a 0.3201-point reduction in stress scores (p = 0.043). Unlike the depression and anxiety models, gender was significant, with female participants reporting higher stress levels than males (p < 0.001). Age was also negatively associated with stress scores (p = 0.010).

  
  

1. Introduction

Mental health is a key determinant of overall well-being and it has gained prominence in recent years, (World Health Organization, 2022). In the general population, the most common mental health concerns relate to depression, anxiety, and stress. The term common mental disorders refers to depression and anxiety disorders due to their high prevalence in the population (World Health Organization, 2017). A global meta-analysis found that 29.2% of individuals report experiencing a common mental disorder at some point in their lifetime (Steel et al., 2014).

However, it is important to distinguish between the emotional states of depression, anxiety, and stress and clinically diagnosed affective disorders. While many individuals experience fluctuations in these emotional states, most do not meet the diagnostic criteria for clinical affective disorders, as their symptoms are often mild, transient, and do not significantly impair daily functioning (American Psychiatric Association, 2022).

Common tools for screening depression, anxiety, and stress levels include the Patient Health Questionnaire-9 (Kroenke et al., 2001) , Generalized Anxiety Disorder-7 (Williams, 2014), Perceived Stress Scale-10 (Cohen et al., 1983), and Depression Anxiety Stress Scales-21 (Lovibond & Lovibond, 2011). These instruments are widely utilized in both clinical and research settings to assess the presence and severity of depressive, anxiety, and stress-related symptoms. It should be noted that while these tools allow for quick and relatively reliable assessments of subjective symptom severity in individuals, they are fundamentally different from evaluations conducted by licensed psychiatrists (Andreou et al., 2011; Levis et al., 2019; Plummer et al., 2016; Villarreal-Zegarra et al., 2023).

Among the various factors influencing mental health, physical activity plays a crucial role in improving both physical and psychological outcomes (World Health Organization, 2020). The American College of Sports Medicine (ACSM) recommends engaging in aerobic exercise 3–5 days per week, accumulating at least 150 minutes of moderate-intensity exercise or 75 minutes of vigorous-intensity exercise per week for an improvement of overall health, including mental health. Alternatively, individuals can aim for approximately 7,000–8,000 steps per day to achieve similar health benefits (American College of Sports Medicine, 2021). Specific studies on the benefits of higher daily step counts on mental health found that Individuals with more than 5000 steps per day has significantly lower depression scores (Bizzozero-Peroni et al., 2024).

This study aims to:

1. Examine the correlation between step counts measured from the Sahha app and mental health levels as measured by DASS-21 (Depression, Anxiety, and Stress scores).

2. Quantify the change in DASS-21 Depression, Anxiety, and Stress scores per 1,000 additional steps.

   
   

   
   

2. Methods

2.1 Data Sources and Participants

The study was conducted between February 2023 and June 2023. Participants were recruited from participant recruitment services. Inclusion criteria include i) age from 18-65, ii) has a smartphone (at least Android version 8+ or iPhone 6) with internet connection, iii) proficient in English.

During this period, a total of 6,482 DASS-21 responses were collected from 661 unique participants. Participants also provided step count data collected via smartphone sensors. The step count data for the 7 days preceding each DASS-21 response was mapped to the corresponding mental health assessment.

After filtering out responses with insufficient step count data, the final dataset comprised 1,835 DASS-21 responses from 301 unique participants. The dataset includes detailed demographic information such as age and sex for all participants.

2.2 Data processing and Statistical analysis

Step count data over the 7 days preceeding a DASS-21 response was average to obtain an average daily step count associated with each DASS-21 response. To account for intra-individual correlation, we aggregated DASS-21 responses from the same user to obtain mean values of daily step counts and DASS-21 scores for each participant. The step count was divided by 1000 to improve interpretability of the coefficients.

To examine the association between daily step count and anxiety, depression, and stress scores from the DASS-21, we perfromed multivariate linear regression with age and gender as covariates

• Model:

  $score = \beta_0 +\beta_1age+\beta_2gender+\beta_3*daily\_steps$

• Where:

  • Score refers to depression_score, anxiety_score, or stress_score

  • daily_steps refers to the the average number of steps per day in the 7 day before the participant responded to the DASS-21.

  • Gender refers to the gender reported at study on-boarding.

    
    

3. Results

3.1 Depression score

In the depression model, the coefficients for age ($\beta$, -0.0964; 95% CI, -0.189 to -0.004; P, 0.041) and total_steps ($\beta$, -0.5631; 95% CI, -0.962 to -0.164; P, 0.006) were statistically significant. The coefficients for gender was not statistically significant ($\beta$, -1.3827; 95% CI, -3.475 to 0.709; P, 0.194).

3.2 Anxiety score

In the anxiety model, the coefficients for age ($\beta$, -0.1024; 95% CI, -0.160 to -0.045; P, 0.001) and total_steps ($\beta$, -0.2750; 95% CI, -0.523 to -0.027; P, 0.030) were statistically significant. The coefficient for gender was not found to be statistically significant ($\beta$, -0.9273; 95% CI, -2.230 to 0.375; P, 0.162)

3.3 Stress score

In the stress model, gender ($\beta$, -3.0504; 95% CI, -4.676 to -1.425; P, <0.001), age ($\beta$, -0.0947; 95% CI, -0.167 to -0.023; P, 0.01), and total_steps ($\beta$, -0.3201; 95% CI, -0.630 to -0.010; P, 0.043) were all found to be statistically significant.

4. Discussion

Across the three models (depression, anxiety, and stress), the significance of the variables gender, age, and total steps shows distinct patterns.

Gender was not a statistically significant predictor in the depression model or the anxiety model. This suggest that there are no meaningful differences in depression or anxiety scores between genders in this sample. However, in the stress model, gender was highly significant ( $\beta$ = -3.0504; 95% CI, -4.676 to -1.425; P < 0.001). This suggest that female participants scored 3.0504 points higher on the stress scale than male participants.

Age was a statistically significant predictor across all three models. Age also has a negative coefficient in all 3 models (-0.0964, -0.1024, and -0.0947 in the depression, anxiety, and stress models respectively). The negative coefficients indicate that older individuals tend to have lower scores for depression, anxiety, and stress.

Total steps was also a significant predictor in all three models and has a negative coefficient, reinforcing the relationship between physical activity and mental health. This suggest that within our sample, each additional 1000 average steps per day is associated with a 0.5631, 0.2750, and 0.3201 point decrease in the depression, anxiety, and stress scale of the DASS-21 respectively.

5. Limitations

• DASS-21 rely on subjective responses, which may introduce reporting bias.

• There are known in inaccuracies in smartphone derived step counts which could under or overestimate the effect sizes of step count on the scores (Case et al., 2015). However, our findings here are highly consistent with existing literature thus, we do not expect the findings to be significantly altered by a higher measurement accuracy.

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6. Conclusion

Understanding the relationship between step counts and depression can provide valuable insights into behavioral interventions for mental health. By showing the effects of increased step count on standardized measures of stress, anxiety, and depression, this study contributes to the growing body of evidence supporting physical activity as a modifiable factor in mental well-being.