VO₂max intervals
Research-informed interval protocols — 30/30, Norwegian 4×4, Billat, Tabata. Designed to train aerobic capacity, on any cardio machine or outdoors.
Your watch tracks your VO₂max. spira trains it.
Guided intervals that tell you what to do, when to push, when to ease — with a programme that builds week after week.
Coming to iPhone.
Put your phone down. Follow the voice.
Every session is audio-guided. You start a protocol, lock your phone, and train. The voice carries you — when to push, when to ease, when you've finished.
Breathwork protocols
Breathing trained as physiology. Five protocols for specific moments: focus, downshift, balance, recovery, sleep.
A plan that builds on itself.
Six-week programmes — Foundation, Build, Peak — carry you from short intervals to sustained efforts. Each session grows from the one before. Follow today's; the arc takes care of itself.
Heart rate as the signal.
A Bluetooth chest strap (Polar H10, Garmin HRM) gives the most reliable live heart rate — your zone bar lights up in real time, even at high intensity. Some watches broadcast heart rate too; check your model. After a session, Apple Health brings your data in from Apple Watch, Oura, and other connected devices, so your peak and recovery still land in spira. Without any sensor, spira is complete — audio, structure, and perceived effort carry the full session; heart rate simply adds another layer.
Why VO₂max
VO₂max is the ceiling of your aerobic capacity — and one of the most studied markers in the research on cardiovascular fitness and longevity. It fades with age, yet it answers to training in every decade of life. spira trains it directly: research-informed intervals that lift the ceiling, and breathwork that strengthens recovery.
Built for people who think in decades, not weeks.
Read more in Learn →FAQ
- What is spira?
- spira is an audio-guided physiological training system with two modules: VO₂max interval training and breathwork protocols. Sessions are voice-guided and designed to run hands-free.
- Do I need a heart rate monitor?
- spira's audio guidance works fully without any device — that's the complete experience. For live heart-rate zones during a session, a Bluetooth chest strap is the most reliable, even at high intensity; some Garmin and Whoop devices can broadcast heart rate too, so check whether yours does. Live heart rate on Apple Watch is coming with the upcoming spira Watch app — for now, Apple Watch data appears after your session through Apple Health, alongside Oura, Withings, and other connected devices.
- What devices is spira available on?
- spira is built for iPhone.
- Is spira free?
- spira includes free VO₂max and breathwork protocols, with premium protocols and programmes available.
- Is this medical advice?
- No. spira is for training guidance only and is not medical advice. Consult a physician before beginning any intense exercise programme.