Health Glossary
22 key health, fitness, and wearable technology terms explained.
Biomarker
Heart Rate Variability (HRV)What HRV is, why higher is usually better, and what your wearable's number really means for recovery and health.…
SpO2 (Blood Oxygen Saturation)What SpO2 measures, normal ranges, and why wearables track blood oxygen for heal…
Cardiac EfficiencyHow cardiac efficiency reflects your heart's ability to deliver oxygen with mini…
Sleep
Sleep Stages (REM, Deep, Light)The four sleep stages explained — what each does for your body and how wearables…
Sleep Quality ScoreWhat sleep quality score means, how it's calculated, and how to improve it.…
Sleep EfficiencyWhat sleep efficiency means, how it's calculated, and what's a good percentage.…
Sleep HygieneEvidence-based sleep hygiene practices that improve sleep quality and overall he…
Fitness
Training LoadWhat training load measures, acute vs chronic load, and how to avoid overtrainin…
Zone 2 TrainingWhy Zone 2 training is the foundation of endurance fitness and longevity.…
Active RecoveryWhat active recovery is, why it works better than complete rest, and how to do i…
Body
Basal Metabolic Rate (BMR)What BMR is, how it's calculated, and why it matters for weight management and h…
TDEE (Total Daily Energy Expenditure)What TDEE is, how it differs from BMR, and how to use it for fitness goals.…
BMI (Body Mass Index)What BMI is, its limitations, and why body composition matters more than BMI alo…
Visceral FatWhat visceral fat is, why it's dangerous, and how smart scales measure it.…
Wearable Metric
Body BatteryWhat Garmin Body Battery measures, how it works, and what it means for daily ene…
Stress ScoreHow wearables measure stress using HRV and what stress scores mean for your heal…
Science
Autonomic Nervous System (ANS)How the autonomic nervous system controls heart rate, stress response, and recov…
RMSSD (HRV Metric)What RMSSD means, how it's measured, and why it's the gold standard HRV metric f…
Bioimpedance Analysis (BIA)How smart scales use electrical impedance to measure body fat, muscle mass, and …
Wellness
MyBodyAI
Body Status ScoreMyBodyAI's composite health score — how 12 indices combine into one overall body…
Strain ScoreHow MyBodyAI calculates your daily strain from activity, stress, and physiologic…