Training Zones Quick Reference
Zones — bike, run, and swim — know exactly when to retest and update your zones.
🎯 Quick Reference: Training Zones
Use this page as your go-to reference for all training zones. Find your metric (HR, power, pace, or swim) and train in the right zone every time.
🏃 Zone Descriptions
| Zone | Name | Purpose & Feel |
|---|---|---|
| ZR | Recovery | Stupid easy. Moving without sweating. Like a stroll with a 2-year-old. Flushes the system and prepares you for upcoming workouts. |
| Z1 | Aerobic Endurance | Where most of your training lives. Builds your aerobic base. |
| Z2 | Endurance Tempo | Used for intervals and specificity sets. |
| Z3 | Threshold | Increases pace/power relative to VO2max. Short intervals up to 30 minutes. |
| Z3+ / Z4 | Best Effort | All-out short efforts. Speed work 4-12 weeks before race. Example: 8×½ mile repeats progressing to max effort. No specific HR/pace targets. |
🚴 Bike Zones
Power (Watts)
| Zone | % of FTP |
|---|---|
| ZR | < 65% |
| Z1 | 65–79% |
| Z2 | 79–89% |
| Z3 | 89–100% |
Heart Rate (Bike)
Tip: Use power as your primary anchor on the bike and HR as a “reality check” for heat, fatigue, and stress.
| Zone | % of Max HR |
|---|---|
| ZR | ≤ 76% |
| Z1 | 80–86% |
| Z2 | 86–93% |
| Z3 | 93–100% |
🏃♂️ Run Zones
Critical Speed/Pace
| Zone | % of Critical Speed |
|---|---|
| ZR | 70–80% |
| Z1 | 80–88% |
| Z2 | 88–95% |
| Z3 | 95–105% |
Heart Rate (Run)
Note: Run HR zones are typically 5-12 beats (BPM) HIGHER than bike HR zones.
| Zone | % of Max HR |
|---|---|
| ZR | ≤ 76% |
| Z1 | 80–86% |
| Z2 | 86–93% |
| Z3 | 93–100% |
🏊 Swim Zones
Core Principle: Hold the water with your catch and bring your body over that hold. The water doesn't move — you move past it. Clean, controlled, connected.
| Zone | Name | Technique & Feel |
|---|---|---|
| ZR | Feel & Float | Super easy. No kick, slow arms. Firm catch with technical precision — just less effort and slower tempo. Never lose connection to the water. |
| Z1 | Easy Rhythm | No kick, but more rhythm. Hold water on one side, move over it as the other arm sets up. Fluid left-to-right movement, catch to catch. |
| Z2 | Ironman/70.3 Pace | Add light kick. Hold water firmly, body moves over stable catch. Steady rhythm, high hips, clean momentum from catch to catch. |
| Z3 | Olympic/Sprint Pace | More kick, faster turnover. Hold the water and move yourself over it. Strong catch, purposeful rotation, fast but never rushed. |
Critical Speed (Swim)
Same as Critical Speed for run — use the same percentages.
Testing for Accurate Zones
Regular testing is essential for accurate zones.
Why Zones Change
Heart Rate (HR)
| Factor | What It Does to HR / Zones |
|---|---|
| Aerobic fitness improves | Aerobic fitness improves – first testing can be off, related to current fitness and body physiolgoy (time off, recovery, dehydration). |
| Day-to-day variability | Day-to-day variability – Sleep deprivation, dehydration, heat, altitude, stress, caffeine, illness, and what you ate can all affect HR by 10-15 bpm for the same effort. This is why a single test is only a snapshot of that exact day. Trends should be seen and as season changes, so should your HR zones for a time. |
| Fatigue accumulation | Fatigue accumulation – Chronic fatigue or overtraining can cause HR to be suppressed (can't get HR up) or elevated (HR spikes easily) relative to effort. Heavy training load temporarily affects HR response until you recover. |
| Testing method | Testing method – Different tests produce different threshold HR values. A 20-min field test, ramp test, true max-effort test, and lab lactate test will each yield slightly different numbers because they stress different energy systems and durations. Races are the TRUE TEST. |
| Aging | Aging – Max heart rate declines naturally over time (typically ~1 beat per year after age 30), which shifts all HR zones downward even if fitness remains constant. |
Critical Power (CP) and Critical Speed (CS)
| Factor | What It Does to CP / CS |
|---|---|
| Training adaptations | Training adaptations – Base training increases aerobic capacity. Build/Threshold blocks raise your sustainable power/pace at threshold. |
| Detraining | Detraining – Time off or reduced volume causes CP/CS to decline within 2-3 weeks. |
| Fatigue state | Fatigue state – Heavy training load suppresses CP/CS temporarily. Fresh legs after a taper can reveal 5-10% higher values. |
| Training block focus | Training block focus – VO₂ Max work increases peak power but may not shift CP. Threshold work directly raises CP/CS. |
| W′ and D′ (anaerobic reserve) | W′ and D′ (anaerobic reserve) – These can change independently of CP/CS based on training focus. |
Bottom line: All metrics change as your physiology evolves. Regular retesting (every 6-8 weeks) ensures zones match your current fitness.
🎯 How to Know You're in the Right Zone
Beyond the numbers — here's how each zone should actually feel:
| Zone | Breathing | Talk Test | What It Feels Like |
|---|---|---|---|
| ZR | Nasal breathing easy | Full conversation, laughing | Could do this all day. No effort sensation. Recovery happening. |
| Z1 | Comfortable breathing | Full sentences easily | Comfortable. Building aerobic base. Could maintain for hours with proper fueling. |
| Z2 | Controlled, rhythmic | Short phrases, 3-5 words | Working but sustainable. Half-Ironman race feel after solid base training. Controlled effort. |
| Z3 | Deep, purposeful | Single words, grunts | Hard but controlled. Olympic race effort at top end. Cannot sustain for more than 30-60 minutes. |
| Z3+/4 | Gasping | Cannot talk | All-out effort. Short duration only. Quality over quantity. Stop when form breaks down. |
Red Flag: If your heart rate doesn't match how hard the effort feels, something is off. High HR with low effort may indicate overtraining, illness, dehydration, or heat. Low HR with high effort may mean your zones need updating or you're fatigued.
❌ Common Mistakes Athletes Make
Big picture: Most athletes blur their zones — easy days too hard, hard days too easy, and zones never updated. Fix these and training gets instantly better.
Mistake #1: Going Too Hard on Easy Days
The problem: Turning Z1 into Z2, or ZR into Z1. This is the most common mistake.
Why it matters: Easy days enable hard days. If you're always in Zone 2-3, you'll never be fresh enough to execute quality workouts properly.
The fix: Slow down more than feels reasonable. If it feels "too easy," you're probably doing it right.
Mistake #2: Not Going Hard Enough on Hard Days
The problem: Z3 workouts become Z2 efforts because you're tired from going too hard on easy days.
Why it matters: Your body adapts to the stimulus you give it. Mushy middle-zone training doesn't create the adaptations you need.
The fix: Prioritize recovery so you can truly execute quality sessions. Better to skip a workout than do it at the wrong intensity.
Mistake #3: Ignoring How You Feel
The problem: Staring at your watch/power meter and ignoring what your body is telling you.
Why it matters: Numbers are a guide, not a mandate. Illness, stress, heat, altitude, and fatigue all affect your ability to hit zones.
The fix: Use zones as a guide but listen to your body. If Z1 feels like Z3, back off regardless of what your device says.
Mistake #4: Never Updating Zones
The problem: Using the same zones for months or years as fitness changes.
Why it matters: As you get fitter, your zones change. Old zones lead to undertraining or overtraining.
The fix: Retest every 6-8 weeks or when workouts feel dramatically easier/harder than they should.
🔄 When to Update Your Zones
Retest your zones every 6-8 weeks, or at these key moments:
- After a training block (Base, Build, VO₂ Max) to capture fitness changes
- 2-3 weeks before an A-race to set accurate race-day pacing targets
- When workouts feel consistently wrong (too easy or too hard for weeks)
- After extended time off (injury, illness, off-season)
- Post-season to establish new baseline for next training cycle
Signs Your Zones Need Updating
Zones may be too low if:
- You can hold "threshold" pace while having full conversations
- Heart rate is consistently 5-10 beats below zone targets
- Workouts that used to be hard now feel moderate
Zones may be too high if:
- Easy days leave you exhausted
- You can't complete intervals at prescribed zones
- Heart rate spikes immediately and won't settle
How to Know You're Improving
True progress shows up in multiple ways — not just going faster.
Signs You're Improving
- CP/CS increases
-
- Your Critical Power (bike) or Critical Speed (run) rises over training blocks
-
- You can hold threshold longer (improved TTE - time to exhaustion)
- Heart rate and effort relationship improves
-
- Same power/pace requires lower heart rate
-
- Same heart rate produces more power/pace
- Same heart rate produces more power/pace
- Form holds late in workouts
Remember: Fitness builds in training blocks, not week to week. Track long-term trends through regular CP/CS testing and work with your coach to adjust training as your physiology evolves.
🏁 Race Day Zone Application
Golden Rule: Your ability to execute zones in training determines your ability to execute them on race day.
IRONMAN (Full Distance)
- Swim: Z1-low Z2, controlled and relaxed
- Bike: Upper Z1 to low Z2 (68-76% of CP/FTP for most athletes). Stay disciplined.
- Run: Start Z1-low Z2, can build to mid Z2 in final 10K if feeling strong
IRONMAN 70.3
- Swim: Low-mid Z2, finding rhythm quickly
- Bike: Mid Z2 to upper Z2 (78-84% of CP/FTP). Controlled throughout.
- Run: Z2, building to Z2-Z3 in final 5K if you have it
Olympic Distance
- Swim: Mid-high Z2, race pace from the start
- Bike: Upper Z2 to low Z3 (85-95% of CP/FTP). Ride like the run matters.
- Run: Z2-Z3, can touch Z3+ in final 2K
10K (Road)
-
Run: Settle into mid Z2 early, then build toward Z2–Z3.
The final 2K can touch Z3+ if pacing has been solid.
Should feel “comfortably hard,” not all-out from the start.
Half Marathon
-
Run: Spend most of the race in Z2.
First 5–8K in low Z2, middle miles in solid Z2, and in the final 5K you may build toward high Z2 or low Z3 if you’re feeling strong.
Marathon
-
Run: Start in upper Z1 to low Z2 for the first 10–15K.
Middle of the race stays in low–mid Z2.
If nutrition and pacing have gone well, drift toward mid–high Z2 in the final 10K.
Going above that too early will cause problems later.
Cycling & Gravel Events
Road Time Trial (~40K)
-
Bike: Upper Z2 to low Z3 (around 90–100% of CP/FTP).
First 5–10 minutes slightly under target, then settle in.
Slight lift near the finish if you have the legs.
Road Gran Fondo / Century (3–6 hours)
-
Bike: Mostly Z1–Z2 with short surges into Z3 on climbs or accelerations.
Aim for average/normalized power in mid Z2.
Spending too much time in Z3 early will come back to bite you later.
Gravel 50–70 miles
-
Bike: Upper Z1 to mid Z2 (about 70–80% of CP/FTP).
Back off on long climbs if heat or traction are issues.
Think “all-day steady” with occasional Z3 pops only when necessary.
Gravel 100+ miles / Ultra Gravel
-
Bike: Z1–low Z2 (around 65–75% of CP/FTP) for most of the day.
Ride climbs patiently to avoid HR spikes.
Focus on fueling, hydration, and smooth riding.
If you feel strong in the final 60–90 minutes, allow effort to creep toward mid Z2 to as fast as you can go!