Blog
Active calories vs total calories: What the numbers on your watch really mean
Active vs total calories explained: what each number means on your Apple Watch, which one to track, and how your daily calorie burn changes with age.
Average heart rate by age: Normal ranges, charts, and what yours means
Average heart rate is not the same as resting pulse. Learn normal ranges, warning trends, wearable limits, and practical ways to improve fitness.
Blood oxygen level: What SpO2 means and how to keep it optimal
Learn what a normal blood oxygen level (SpO2) is, what causes low oxygen saturation, and 8 proven ways to improve it. Includes a chart by age and tracking tips.
Endurance score: What it measures and how to improve it
Endurance score estimates sustained aerobic capacity from VO2 max and recent training. Learn the levels, trends, and habits that improve cardio fitness.
Intensity minutes: How to hit your weekly exercise goal (and why it matters)
Learn what intensity minutes are, why the WHO recommends 150 per week, and how to track them with your Apple Watch. Science-backed strategies to move smarter.
Max heart rate by age: How to calculate it and use exercise zones
Learn how to calculate your maximum heart rate by age using proven formulas, understand the 5 exercise zones, and train smarter for better health.
Pace of aging: How fast is your body actually getting older?
Learn what pace of aging means, how DunedinPACE measures it, and 7 proven ways to slow down how fast your body ages. Science-backed guide.
Resilience score: What it really measures and how to improve it
Learn what a resilience score measures, how it's calculated from HRV, sleep, and stress data, and 7 proven strategies to build lasting physiological resilience.
Respiratory rate by age: What's normal and when to worry
Learn what a healthy respiratory rate looks like for every age, what causes it to change, and how to track it. Includes normal range chart and sleep data.