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Activity Score Scientific Reference

The Activity Score covers multiple dimensions of physical activity, offering a comprehensive measure of an individual's daily movement. The score is designed to encourage users to adopt healthier lifestyles by promoting daily physical activity and reducing inactivity. The Activity Score combines several key factors, including steps, active hours, active calories, intense activity duration, extended inactivity, and floors climbed.

How the Activity Score is Calculated

The Activity Score is calculated by aggregating the values from various movement-related metrics, with each metric contributing a specific weight to the final score. This allows for a balanced and comprehensive reflection of the user’s daily physical activity. The factors are individually assessed and combined into a weighted formula to generate the overall score.

Score Design

The Activity Score is derived by factors, with each factor weighted slightly differently based on the research of the importance of that factor to overall health.

Each factor is normalised to ensure comparability across users with different levels of activity and fitness. The score is on a scale of 0 to 100, with higher scores indicating greater overall sleep health.

Activity Factors: Key Aspects of Movement

The Activity Score incorporates multiple factors that define an individual’s movement throughout the day. Here’s a breakdown of each factor and its contribution to the final score:

  1. Steps : Increasing daily step count has been shown to significantly reduce mortality rates. Each additional 1,000 steps per day is associated with a 6–36% reduction in all-cause mortality risk over the next 4-10 years and a 5-21% reduction in cardiovascular-related deaths over the next 2-5 years ( Hall et al., 2020 ). Individuals with a daily step counts of 8,000 and 12,000 also exhibited a lower rate of all-cause mortality than individuals with a daily step count of 4,000 over the next 10 years ( Saint-Maurice et al., 2020 ).

  2. Moderate and Intense Activity Duration : Different demographics and age groups have different pertinent health-related outcomes. Physical activity is a key component in influencing health-related outcomes across age-groups and demographics. For demographics different outcomes are seen corresponding to health requirements by the WHO guidelines on physical activity and sedentary behaviour ).

    • In children and adolescents (age 5-17), moderate and vigorous physical activities are associated with improved cardiorespiratory fitness, muscular fitness, metabolic health, bone health, cognitive and academic performances. 60 minutes per day of moderate to vigorous-intensity activity is recommended for children and adolescents
    • In adults (age 18-64), higher levels of physical activity are associated with lower risk of all-cause mortality, hypertension, type-2 diabetes, and lower measures of adiposity. 150–300 minutes of moderate-intensity aerobic physical activity or at least 75–150 minutes of vigorous-intensity aerobic physical activity is recommended for adults and older adults. In older adults (age ≥ 65), physical activity improves physical functions and reduce age-related loss of physical functions.

  3. Active Hours : Active hours is a simple and widely used method to track physical activity relative to a predefined target. Users are encouraged to get up to move for at least 3 minutes or get in a 100 steps as many hours as possible throughout the day.

  4. Active Calories : Tracking active calorie burn helps users achieve desired calorie expenditure for weight loss and weight control objectives. This measure shows how activity is contributing to tangible caloric goals for the user.

  5. Extended Inactivity : A sedentary lifestyle is associated with decreased cardiac output and systemic blood flow, insulin insensitivity, and increased activation of the sympathetic nervous system ( Park et al., 2020 , Hadjuk and Chaudhry, 2016 ). Overall, a sedentary lifestyle contributes to obesity, worse health outcomes, and a lower quality of life ( Manson et al., 2004 ).

  6. Floors Climbed : Daily stairs climbing is associated with improved VO2 max, reduced LDL cholesterol levels, and decreased risk of metabolic syndrome ( Boreham et al., 2005, Whittaker et al., 2021 ).

Normalization and Adjustments

The Activity Score is normalized to account for differences in fitness levels and demographics. For example, older adults may have a different step goal or calorie burn threshold compared to younger adults. This ensures that the score reflects individual health needs rather than a one-size-fits-all target.

Scientific References

Here is a list of the research papers and sources that support the factors used in Sahha's Activity Score calculation:

  • Hall, C., et al. (2020). Impact of daily steps on mortality. International Journal of Behavioral Nutrition and Physical Activity . Link
  • WHO guidelines on physical activity and sedentary behaviour. (2020). World Health Organization . Link
  • Park, J. H., et al. (2020). The risks of a sedentary lifestyle. Korean Journal of Family Medicine . Link
  • Boreham, C. A., et al. (2005). Stairs and cardiovascular fitness. British Journal of Sports Medicine . Link
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