Minterval: Fitness Timer

The 4×4, measured properly — so you can tell whether it worked.

Choose your work interval, recovery time and number of rounds—for example, four minutes hard, three minutes easy, repeated four times. Minterval runs the session, then measures what it did to you: how long you held your target band and how quickly your heart rate came down afterwards.

It does not invent numbers. No estimated VO₂ max, no population percentile, no made-up score. Every figure on the screen was measured on you, or it is not there.

WHAT IT MEASURES • Time held in your target band, round by round • Heart recovery — HRR60 and HRR120, using the same recovery protocol each time • Your history: this week free; month, year and all-time with Pro • 4×4 Test Lab — a fixed benchmark with a saved profile, quality checks and every attempt retained

BUILT TO BE USED IN A GYM • A recorded coach who counts you in and calls the last minute • Your own music from Apple Music — a song, playlist or whatever is already playing • A PowerSong that lifts in the closing minute of every work round • Apple Watch and Apple TV companions • Written sessions including pyramids, ladders and ramps

HONEST ABOUT WHAT IS FREE The timer is free: unlimited rounds, warm-up and cool-down, live heart rate, five zones, heart recovery and this week’s Gym Data.

Minterval Pro is one purchase — no subscription — and adds saved sessions, the 4×4 Test Lab, history beyond a week, the Apple Watch companion, custom maximum heart rate and zones, and the FLUID 1 music pack.

PRIVATE BY DEFAULT No account. No sign-in. Nothing is sent to us. Workout history remains on your devices and in Apple Health; Minterval has no analytics or server.

Heart measurements require an Apple Watch or compatible Bluetooth heart-rate monitor. The interval timer works without either.