spira

The physiology of performance.

Audio-guided VO2max intervals and breathwork.
iOS & Android — coming soon.

Request early access

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01 — Built for

Built for people
who already train.

You own a heart rate monitor.

You've done Zone 2.

You know VO2max is the number that matters.

You track your HRV. You've worn a Whoop.

You don't need motivation — you need a system.

02 — What is Spira

Two modules.
One system.

Spira is an audio-guided physiological training system that combines VO2max interval training and breathwork protocols. Put your phone down. Follow the voice. No screen dependency — the audio guides everything.

VO2max

Push your ceiling.

Structured interval protocols from 30/30 to Norwegian 4×4. Each session is voice-guided, timed to the second, and calibrated to your heart rate zones.

Breathwork

Lower your floor.

Precise inhale-exhale rhythms with a visual breathing circle. Downshift, Focus, Recovery, Sleep. Nervous system control — not meditation.

01

Choose a session.

02

Put your phone down.

03

Follow the voice.

04

Track your adaptation.

03 — Why Spira

Know what to do.
See what changed.

01

Structured programs.

6-week guided cycles. Each session builds on the last. You always know what to do today.

02

Physiological tracking.

HR recovery, target zone time, session consistency. Progress measured by adaptation — not streaks.

03

Audio-first precision.

Cues timed to the second. No missed intervals. No delayed prompts. Trust the system — move.

04 — Heart rate guided

Your physiology
drives the session.

Spira is designed for major heart-rate ecosystems — Apple Watch, Polar, Garmin, WHOOP, Samsung, and BLE monitors. During sessions, heart rate guidance adapts in real time. Below target — push harder. Above ceiling — ease off. The voice responds to your body.

During effort

168 bpm

Zone 4 — Hard

Target reached. Audio cue: silence. You're where you need to be.

During recovery

142 bpm

Dropping

Heart rate recovering. No interruption. The system watches — you rest.

05 — Protocols

Research-backed.
Not improvised.

Every protocol is grounded in exercise physiology. Billat, Tabata, Norwegian — validated methods, not random timers.

30/30 30s effort, 30s recovery. The accessible entry point to VO2max training.
15/15 Short, sharp intervals. Higher nervous system demand. Explosive aerobic power.
1min / 1min Sustained effort. The bridge between short intervals and long-form work.
Norwegian 4×4 Premium 4 minutes at 90-95% max HR. The gold standard of VO2max development.
Billat Premium 2 × 15 rounds. Advanced volume protocol for sustained aerobic adaptation.
Tabata Premium 20s all-out, 10s rest. 8 rounds. Maximum intensity in minimum time.
Breathwork 5 protocols — Downshift, Focus, Balance, Recovery, Sleep. Precise breath rhythms for nervous system regulation.

06 — Questions

Frequently asked.

What is Spira? Spira is an audio-guided physiological training system that combines structured VO2max interval training and breathwork protocols with heart-rate zone guidance and 6-week training programs.
What makes Spira different from a regular timer? Spira is audio-first, heart-rate aware, and built around structured programs. Unlike manual timers, Spira guides with voice cues, adapts to your heart rate during long intervals, and tracks physiological progress over time.
Which heart rate monitors will work? Spira is being designed for major heart-rate ecosystems including Apple Watch, Polar, Garmin, WHOOP, Samsung via Health Connect, and standard Bluetooth heart rate monitors. Support rolls out progressively.
Is Spira free? Spira offers a free tier with core VO2max and breathwork protocols. Premium unlocks advanced protocols, structured 6-week programs, and detailed progress tracking.
How is Spira different from Calm or Headspace? Calm and Headspace are meditation apps that include breathwork as one feature. Spira is a physiological training system — breathwork protocols with precise timing, animated breathing circle, and measurable outcomes. No meditation, no sleep stories. Pure breath control grounded in physiology.
Can breathwork improve recovery and HRV? Yes. Controlled breathing with extended exhales activates the parasympathetic nervous system, improving heart rate variability and accelerating recovery. Spira's Recovery and Sleep protocols are designed specifically for this.
iOS and Android? Both. Spira is coming to iOS and Android. Join the waitlist for early access.

Build your engine.

Private beta access.
iOS and Android.

No spam. Early access only.