Caynax HIIT is a free powerful interval timer for HIIT Tabata cardio and any timed workout — now with live Bluetooth heart-rate monitoring color-coded heart-rate zones full workout history and progress tracking.

Want to burn fat build stamina and get more out of every minute? High-intensity interval training (HIIT) alternates short bursts of all-out effort with brief recovery — proven to improve fitness and fat burning in workouts as short as 9–20 minutes. Caynax HIIT keeps the timing the cues and the tracking for you so you can focus on the work.

★ Trusted by hundreds of thousands of athletes — 4.7★ and growing.

❤️ LIVE BLUETOOTH HEART RATE + ZONES
• Pair any Bluetooth LE heart-rate strap or armband (standard Heart Rate Profile).
• Live BPM during your workout — current min average and max.
• 5 color-coded zones from your age or a custom max-HR with a live graph.

📈 HEART-RATE CHARTS & HISTORY
• Every session records your full heart-rate curve colored by zone.
• A history detail screen overlays your HR on each stage (warm-up / work / rest / cool-down).

📊 WORKOUT HISTORY & PROGRESS TRACKING
• Automatic history of every session: date duration rounds calories.
• Streaks a calendar weekly trends and personal records.
• Per-workout history time-in-zone a weekly goal notes and RPE.

✨ TRY PRO FREE FOR 7 DAYS
All premium features — heart-rate monitoring charts advanced analytics and progress tracking — are unlocked free for your first 7 days. No commitment.

WHAT IS HIIT?
High-intensity interval training alternates short intense anaerobic effort with less-intense recovery. A typical session lasts 9–20 minutes: a warm-up six to ten high-intensity reps separated by medium-intensity recovery then a cool-down. A common protocol uses a 2:1 work-to-rest ratio — e.g. 30–40s of hard sprinting then 15–20s of jogging. It's one of the best ways to get a complete workout when you're short on time.

⚠️ Because of the intensity this training isn't for everyone. Please consult a doctor and a qualified trainer first.

KEY FEATURES
⏱️ Powerful flexible interval timer
• Build unlimited workouts: warm-up work rest rounds and cool-down.
• Create edit duplicate and delete your own workouts.
• Built-in Tabata and Fartlek samples — no stingy 2-workout limit.

🔊 Voice & sound cues
• Voice (TTS) counts down out loud — edit the spoken texts (PRO).
• Beep countdown with built-in beeps or your own sound (PRO).
• Flexible countdown: every second every n-th second or only the final seconds (some options PRO).

🎛️ Built for real training
• Full-screen color-coded stages and a big readable timer.
• "Next interval" preview.
• Rewind backward and forward (PRO).
• Multi-window support; keeps running reliably in the background.

PERFECT FOR: Tabata • HIIT • cardio • CrossFit-style circuits • Fartlek • kettlebell • jump rope • bodyweight • running intervals • boxing rounds • stretching • yoga • and any activity that needs a flexible timer.

FREE vs PRO
Caynax HIIT is free and fully usable. PRO unlocks editable voice texts custom sounds advanced countdown options rewind and the full heart-rate + analytics suite — try it all free for 7 days. A one-time in-app purchase removes ads forever.

When you're done burning fat try Caynax Aerobic Weider Six (A6W) to build a perfect six-pack.

Download Caynax HIIT and turn any space into your interval gym. 💪