2 full-body strength · 3 Hyrox · mobility · recovery. Red badges = VO₂ interval days. Tap a day for the full workout.
Train together: Saturday's race simulation is the one to do as a pair. Everything else you each run at your own effort.
Want variety? Open the 🔄 Swap tab for alternate workouts for each day type — all built to hit the same goal.
🔄 Swap & Variety
Pick any option in a group to replace that day — each one still maximizes the day's goal. Rotate weekly so you never plateau.
🫁 VO₂ Max Engine
Built from Khizzy's Apple Health export — 191,626 HR samples, Apr 2023–Jun 2026.
Key finding: Resting HR has risen ~10 bpm (56→66) and working HR is up ~30 bpm since 2023, despite high step volume. That's aerobic decline + grey-zone fatigue — fixable fast with structured high-intensity work and real recovery.
Z1 66%
Z2 12%
Z3 9%
Z4 7%
Z5 6%
Current intensity mix. VO₂ max is built at the top (Z5) — and only ~6% of time is there, mostly unstructured.
❤️ Your HR Zones
Karvonen · max 196 · resting 60 · use on your watch.
Zone
bpm
Use
Z1 Recovery
<128
Walking, tennis rallies, warm-up
Z2 Endurance
142–155
Aerobic base — most cardio
Z3 Tempo
155–169
Limit — the junk zone
Z4 Threshold
169–182
Hyrox race pace
Z5 VO₂ max
182–196
The driver — 2×/week
🔥 The Two VO₂ Sessions
Slot these into your Hyrox days. They do the heavy lifting for VO₂ max.
Norwegian 4×4
Tue · Run 4 min @ Z5 (182–192), 3 min easy jog. ×4. Then 3 Hyrox stations.
30/30 Intervals
Sat · 30s max effort @ Z5 / 30s easy. ×10–12 after race sim.
Why it works: Holding >90% max HR drives stroke volume and mitochondrial adaptation. Keep everything else easy so you can hit these two hard — fewer truly hard sessions beats scattered grey-zone work.
🌅 Morning Resting-HR Check
Log your watch's resting HR. Your data shows RHR is your reliable fatigue signal — baseline target back toward high-50s.
📈 8-Week Progression
Wk
Intervals
Goal
1–2
4×4 · 30/30 ×8
Rebuild intensity tolerance
3–4
5×4 · 30/30 ×10
Build Z5 volume
5
Deload (½ volume)
Absorb — watch RHR drop
6–7
5×4 · 30/30 ×12
Peak stimulus
8
1.5-mi TT / Hyrox sim
Confirm: lower RHR, faster pace
Track it for real: turn on Cardio Fitness on your Apple Watch + do regular outdoor walks/runs so it logs an actual VO₂ max number to trend.
📅 History
Personalized to Khizzy's heart-rate data · general fitness guidance, not medical advice. Data saves on this device in your browser, per profile.