Estimate your training zones based on Functional Threshold Power (FTP) or Lactate Threshold Heart Rate (LTHR).
Test Configuration
bpm
Anaerobic Threshold is the highest intensity you can sustain for ~60 minutes before lactate accumulation causes rapid fatigue.
Threshold Performance
About this calculator
Overview
Your Anaerobic Threshold (often called FTP for power or LTHR for heart rate) is a key metric for endurance athletes. It marks the boundary where your body can no longer clear lactic acid as fast as it's produced.
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Pro Tips
Use a 20-minute 'all-out' effort to estimate your threshold. Multiply the average by 0.95 to account for the shorter duration.
LTHR is more stable than Max HR and provides a better foundation for zone-based training.
FTP is the benchmark for cycling performance and is used to calibrate training intensity on indoor trainers and power meters.
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Fun Facts
"Elite marathoners can run at ~90-95% of their LTHR for the entire race."
"Your threshold is highly trainable and will shift upward as your fitness improves."
"Environmental factors like heat and altitude can significantly impact your heart rate response."
