Distance Interval Trainer vs Your Stressy

Free to download. Premium, a one-time purchase, unlocks the Apple Watch app (try 3 runs free), Indoor runs and your full history. Run or Bike Through the Finish Line! Break free from boring timers — our app puts the focus on distance-based interval training (though timed intervals are available too). Whether you’re training for 100m, 200m, or even 1000m repeats, simply set your sprint/walk/bike distance and rest distance — we’ll guide you with clear start and stop notifications so you can stay locked in on your workout. Perfect for runners, cyclists, and walkers who want structured, goal-oriented sessions. Seamlessly integrates with your music so you’ll never miss a cue — even mid-song. Pro tip: Continued GPS use in the background may reduce battery life.

Stressy turns what your Apple Watch already measures into one number: your reserve, from 0 to 100%. Sleep fills it. Stress drains it. Calm slows it down. Glance at your wrist or your iPhone and you know how much you have left today. YOUR MORNING STARTS WITH YOUR NIGHT Deep sleep refills your reserve fastest. Stressy reads how your heart and HRV recovered overnight against your own usual, so a short or restless night starts you lower and a good one starts you high. THROUGH THE DAY Every five minutes, your heart is compared with your own calm. Stress drains the reserve in proportion to how stressed you are, calm slows the drain, and mindful minutes recharge it. Workouts and walks count as effort, never as stress. SEE EXACTLY WHY Today shows your whole day in one curve, your stress every five minutes, every activity with what it cost or gave back, and Behind the number: where yesterday ended, last night's recovery, and where your reserve went since you woke up. LOOK AHEAD • Readiness: whether today suits hard training, from your reserve, recovery, sleep and recent training. Plan a workout and see tomorrow's wake-up with and without it. • Bedtime coach: the latest bedtime that still wakes you at 100, 90 or 80%, on a Liquid Glass dial. YOUR WHOLE DAY • Steps: your steps and distance hour by hour and across the week. • Sleep: every stage of the night, deep, core and REM, with the time in each and how your body recovered. • Workouts: the route on a map, time, distance, pace, heart rate and its zones, and what the workout cost your reserve. • Stories: turn your steps, sleep or a workout into a video or image for Instagram and anywhere else, made right on your iPhone. YOUR BODY AGE How old your fitness and habits look, in years: your cardio fitness, resting heart rate, steps and sleep, each against what's typical for your age and sex, combined the way researchers build biological age. Every step of the calculation is shown, with the studies behind it. A wellness estimate, not a medical one. ON YOUR WRIST AND EVERY SCREEN The living tank on Apple Watch, complications and the Smart Stack, plus widgets for your Home Screen and Lock Screen, including today's stress in detail, as bars or as a flowing line, and your steps or distance. MADE FOR iPHONE DUO Open iPhone Duo and your number and your whole day sit side by side: the living tank on one side, Today on the other, with every page opening next to your number. Closed, it works like any iPhone. DESIGNED FOR iOS 26 AND LATER A living liquid tank, glass numbers that hold their own liquid, and Liquid Glass throughout. Light and dark appearance, Dynamic Type, VoiceOver and Reduce Motion. PRIVATE BY DESIGN No account. No servers. No analytics. No ads. Your health data is read on your iPhone and Apple Watch and never leaves them. One price, no subscription. WHAT YOU NEED An iPhone and an Apple Watch. Stressy reads sleep, heart rate, heart rate variability, resting heart rate, cardio fitness, workouts and their routes, distance, active energy, steps and mindful minutes from Apple Health, plus your age and sex for your heart rate zones and Body Age. Wear your watch to sleep for the best results; your personal baseline settles in within about a week. Stressy is a wellness app, not a medical device. Your reserve is an estimate to help you notice how sleep, stress and rest shape your day.