Interval Readiness Checklist: Proceed, Modify, or Postpone

Signal 2 — Readiness trend (short-term context)

What to read

• Use a 3–7 day trend in HRV, resting HR, and TSB (N+One aggregates CTL + ATL = TSB for you).
• Look for direction and magnitude: is the athlete trending toward freshness or fatigue?

Decision rules

• Three green signals (sleep + steady HRV/RHR + neutral/positive TSB): proceed.
• Mixed signals (one low, others OK): reduce dose — fewer intervals, shorter duration, or drop from VO2 to threshold/sweet spot.
• Red (HRV sharply down, RHR up, TSB strongly negative): postpone hard intervals.

Practical example: VO2 max intervals vs threshold session

• If HRV is slightly depressed but TSB is neutral, swap VO2 max intervals for a shorter threshold session or a sweet-spot block. If HRV is sharply down and TSB <-10, avoid both — go aerobic support.

(For more on reading TSB without anxiety, see our guide.)

Signal 3 — Warm-up response (the decisive gate)

A 20–30 minute warm-up is not optional — it’s diagnostic.

What to watch during warm-up

• Power: can you hit 30–60s at 95–105% of planned interval intensity without extreme struggle?
• Heart rate: is HR creeping to interval levels during the warm-up? Rapid early HR rise suggests limited readiness.
• Perceived effort: RPE 1–3 during warm-up is expected; RPE 5+ is a warning.

Quick warm-up protocol (3–5 minute tests inside a 20–30 min warm-up)

1. 10–15 min easy Zone 1–2
2. 3 × 1 min at planned interval intensity with 2 min easy between
3. Note power, HR, and RPE on the third effort

Decision cues from the warm-up

• Green: power near target, HR controlled (no runaway), RPE manageable → execute planned session.
• Amber: power is 5–10% below target or HR higher than usual → reduce dose (fewer reps, shorter intervals, or 90–95% intensity).
• Red: power well below target, HR spikes quickly, or breathing/legs feel heavy → pivot to aerobic support.

How to reduce dose (decisive options — not wishy-washy)

If you land in the mixed zone, choose ONE decisive modification:

• Reduce interval count by 30–50% (e.g., 6 × 3' → 4 × 3')
• Shorten intervals (e.g., 6 × 4' → 8 × 2') to preserve stimulus but lower systemic strain
• Drop target intensity one zone (VO2 → threshold; threshold → sweet spot)

Example: Scheduled 5 × 5' VO2 intervals at 110% FTP. Mixed signals → do 4 × 3' at 105% FTP, or 5 × 3' at threshold power. Be decisive.

If you pivot: what aerobic support work looks like

• Purposeful Zone 2, 60–120 minutes depending on time available
• Shorter aerobic option: 45–60 minutes steady aerobic with a few 10–30s high-cadence accelerations to keep neuromuscular signal

This preserves training intent (aerobic work, technique, mitochondrial stimulus) without adding risky fatigue.

Quick checklist (60–90 seconds before intervals)

• Sleep/recovery: last night ≥7 h and recovery score OK? ✅
• Readiness trend: HRV/RHR and TSB stable or improving? ✅
• Warm-up test: 3rd 1-min test hits power/HR and feels manageable? ✅

If all three ✅ → GO. One amber → Reduce dose. Any red → Pivot to aerobic. Repeat: This is not caution. It is quality control.

Conclusion — Key takeaways

• A brief, three-signal gate (sleep/recovery, readiness trend, warm-up response) prevents low-quality hard sessions and preserves long-term gains.
• Three green: execute. Mixed signals: reduce dose. Red flags: pivot to aerobic support.
• Be decisive: choose one clear modification and stick to it.

Ready to make each session count? Try N+One to get automated readiness scores, CTL/ATL/TSB context, and adaptive session edits — so the plan breaks before you do. The Next Session.