What is anaerobic threshold?

AT is the intensity above which lactate accumulates faster than it can be cleared. Typically 75–85% of max HR. Trained athletes: 80–85%. Beginners: 75–80%. Lactate threshold occurs at ~2–4 mmol/L blood lactate.

How is AT heart rate calculated?

Karvonen: AT_HR = ((MaxHR − RestHR) × AT%) + RestHR. AT% depends on fitness: beginner 75%, intermediate 78%, advanced 82%, elite 85%. Use 208 − 0.7×age for max HR if unknown.

AT pace is the pace you can sustain for ~60 minutes all-out. It correlates with lactate threshold. Elite marathoners run at 85–92% of VO2max for 2+ hours. Improving AT can improve endurance by 5–15%.

How do I find my max HR?

220 − age (simple) or 208 − 0.7×age (Tanaka). Lab testing is most accurate. A hard 5K or ramp test can approximate it. Use the calculator's estimate if unknown.

What is the AT power zone?

For cycling, AT is Zone 4 (80–90% FTP). Power at AT is often 85–95% of FTP for trained athletes. Use heart rate or power for zone targeting.

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Anaerobic Threshold

Calculate anaerobic threshold heart rate, AT pace, power zone. Karvonen method. Training recommendations.

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💪Karvonen

AT Zone — Train at the Right Intensity

80–85% MHR trained, 75–80% beginners. Sustainable ~60 min.

Calculate Results

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Resting HR (bpm)

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at-threshold.txtcalculated

$ at-threshold --karvonen

AT HR

156 bpm

AT Pace

9:26/mi

Max HR

184

Power Zone

Zone 4

Recommendations:

Tempo runs 2–3x/week at AT pace

Intervals 2–5 min slightly above AT

Avoid AT work on consecutive days

Build volume before intensity

Screenshot Summary

Your anaerobic threshold is approximately 156 bpm. Train tempo runs at 9:26/mi. Zone 4: 78–88% of FTP

For educational and informational purposes only. Verify with a qualified professional.

Answer Capsule

AT at ~80–85% MHR for trained, ~75–80% for beginners. Karvonen: AT_HR = ((MaxHR − RHR) × AT%) + RHR. Lactate threshold ~2–4 mmol/L. Improving AT can improve endurance by 5–15%. Sustainable for ~60 min.

📋 Key Takeaways

• AT % of MHR: Trained 80–85%, beginners 75–80%. Karvonen formula: AT_HR = ((MaxHR − RHR) × AT%) + RHR
• Lactate threshold: Occurs at ~2–4 mmol/L blood lactate. AT pace = sustainable for ~60 min all-out
• Improvement: Improving AT can improve endurance by 5–15%. Elite marathoners run at 85–92% VO2max for 2+ hours
• Training: Tempo runs 2–3x/week at AT. Intervals slightly above. Avoid consecutive days. Build volume first

💡 Did You Know?

🧪Lactate threshold occurs at ~2–4 mmol/L blood lactate. Above this, lactate accumulates faster than it can be cleared.Source: British Journal of Sports Medicine

🏃Elite marathoners run at 85–92% of VO2max for 2+ hours. Their AT is highly developed through years of tempo work.Source: ACSM

📈Improving AT can improve endurance by 5–15%. Tempo runs and threshold intervals are the key workouts.Source: TrainingPeaks

⏱️AT pace is sustainable for ~60 minutes all-out. It's the comfortably hard effort—conversation difficult but not impossible.Source: ACSM

💪Trained athletes: AT at 80–85% MHR. Beginners: 75–80%. Fitness level shifts the percentage upward.Source: British Journal of Sports Medicine

🚴For cycling, AT is Zone 4 (80–90% FTP). Power at AT often 85–95% of FTP. Use HR or power for targeting.Source: TrainingPeaks

📖 How It Works

Karvonen Formula

AT_HR = ((MaxHR − RHR) × AT%) + RHR. AT% = 75% beginner, 78% intermediate, 82% advanced, 85% elite. Uses heart rate reserve.

AT Pace

Pace sustainable for ~60 min all-out. Correlates with lactate threshold. Used for tempo runs. Improves with consistent threshold training.

AT Power Zone

Zone 4: 80–90% FTP. Power at AT often 85–95% of FTP for trained cyclists. Use for threshold intervals and tempo rides.

🎯 Expert Tips

🏃 Tempo 2–3x/Week

Tempo runs at AT pace. 20–40 min. Builds lactate clearance. Key workout for endurance.

📊 Use Lab or Field Test

Lab lactate test most accurate. 20-min TT or 30-min steady effort can approximate AT. Re-test every 6–12 weeks.

⏱️ No Consecutive Days

AT work is demanding. Space tempo and threshold sessions. Recovery between key workouts.

📈 Build Volume First

Increase volume before intensity. Base before threshold. 80/20 rule: 80% easy, 20% hard.

⚖️ AT % by Fitness Level

Level	AT % MHR	Typical	Status
Beginner	75%	New to training	⚠️
Intermediate	78%	1–2 years	✅
Advanced	82%	Competitive	✅
Elite	85%	Elite athletes	✅