Body Battery

Do you know how charged you actually are right now?

Body Battery turns your Apple Watch data into a real-time energy score — a single number from 0 to 100 that reflects how much physiological fuel you have left, and how fast you're recharging or depleting.

No guesswork. No manual logging. Just honest, science-backed insight from the sensors you're already wearing.

HOW IT WORKS

Your Apple Watch is constantly measuring your heart rate variability (HRV), resting heart rate, sleep stages, and activity load. Body Battery combines all of these into one continuously updated score using the same science that powers professional recovery tools like Garmin Body Battery and WHOOP — but built natively for Apple Watch and HealthKit.

• Sleep recharges your battery. Deep sleep and REM are your most powerful recovery tools. • Activity drains your battery. Workouts, stress, and physical exertion pull from your reserves. • Your baseline is personal. The app learns your normal over 14 days, so your score is relative to you, not a population average.

KEY FEATURES

Live Energy Score A clean 0–100 battery gauge updated throughout the day as new Apple Watch data arrives. See at a glance whether you're charging or running low.

Sleep Recharge Tracking Each morning, see exactly how much last night's sleep recharged your battery — broken down by sleep efficiency, deep sleep, REM, and wake-after-sleep-onset.

Activity Drain Analysis Every workout and active period is logged with its estimated energy cost, so you can see how much your run, gym session, or stressful afternoon drained your reserves.

Daily Trend Graph A timeline of your battery level across the day — watch it drop during your commute, recover after lunch, then slowly recharge overnight.

Personal Baseline Learning The first 14 days establish your personal HRV, heart rate, and sleep baselines. After that, your score is calibrated to your body — small changes that would be invisible on a population chart become visible to you.

Apple Watch App Glance at your current score right from your wrist. A clean complication for your watch face keeps your energy level in view without opening your phone.

Home Screen & Lock Screen Widgets Add the Body Battery widget to your Home Screen or Lock Screen for an at-a-glance energy check without unlocking your iPhone.

100% Private All data stays on your device. Body Battery reads from Apple Health and never uploads your health data anywhere.

WHAT IT MEASURES

Body Battery uses the following HealthKit data (all read-only): • Heart Rate Variability (SDNN) • Resting Heart Rate • Sleep analysis and stages • Active Energy Burned • Workout sessions • Steps and Exercise Minutes • VO2 Max (where available)

REQUIRES • iPhone with iOS 17.0 or later • Apple Watch Series 4 or later (for sleep stages and HRV) • Apple Health access

Body Battery is a personal wellness tool. It is not a medical device and does not provide medical advice. HRV measurements from Apple Watch are suitable for personal trends and are not clinical-grade. Always consult a healthcare professional for medical concerns.