Alp Fitness Training Zones

Z1 – “Easy” Zone

Easy nose-breathing effort. You should be able to comfortably breathe through your nose and tell a long story to someone next to you without needing to slow down to catch your breath. Breathing is barely above walking breathing rate. 

  • Intensity: Easy
  • Heart Rate: Less than 85% of lactate threshold heart rate (LTHR)
  • Power: Less than 56% of functional threshold power (FTPw)
  • Pace: Slower than 129% of functional threshold pace (FTPa)
  • Purpose: Used to aid recovery from hard days and add to your aerobic base.
  • Also known as: Friel’s Zone 1 or Coggan’s Zone 1

Z2 – “Conversational” Zone

Conversational nose-breathing effort. You should be able to breathe through your nose and hold a back-and-forth conversation with someone running next to you (taking turns to speak). Breathing is moderate and not labored. Once you’ve moved beyond this effort level, you’ve moved beyond your aerobic threshold (AeT).

  • Intensity: At or below your aerobic threshold (AeT)
  • Heart Rate: 85-89% of lactate threshold heart rate (LTHR)
  • Power: 56-75% of functional threshold power (FTPw)
  • Pace: 114-129% of functional threshold pace (FTPa)
  • Purpose: Used more than any other training zone to build the aerobic endurance base, which allows you to better metabolize fat and spare glycogen (stored carbohydrate) as a long duration energy source.
  • Also known as: Friel’s Zone 2 or Coggan’s Zone 2

Z3 – “Comfortably Hard” (Tempo) Zone

Comfortably hard effort above your aerobic threshold (AeT) but below your lactate threshold (LT). You should still be able to breathe through your nose (although deep and labored) while your ability to talk will be limited to 2-3 sentences at a time. 

  • Intensity: Above your aerobic threshold (AeT) for sustained durations
  • Heart Rate: 90-94% of lactate threshold heart rate (LTHR)
  • Power: 76-90% of functional threshold power (FTPw)
  • Pace: 106-113% of functional threshold pace (FTPa)
  • Purpose: Used sparingly as a bridge to threshold work, to build intensive aerobic endurance and improve lactate tolerance; and to simulate marathon-distance race pace.
  • Also known as: Friel’s Zone 3 or Coggan’s Zone 3

Z4 – “Comfortably Hard” (Threshold) Zone

Comfortably hard effort nearing or even crossing just over your lactate threshold (LT). As you approach and cross over your lactate threshold (LT) you may be able to say 5-7 words at a time, but will need to breathe through your mouth.

  • Intensity: Nearing or just crossing over your lactate threshold (LT)
  • Heart Rate: 95-102% of lactate threshold heart rate (LTHR)
  • Power: 91-105% of functional threshold power (FTPw)
  • Pace: 97-105% of functional threshold pace (FTPa)
  • Purpose: Used to raise the lactate threshold by improving lactate tolerance and decreasing lactate accumulation, which allows you to stay aerobic at faster speeds.
  • Also known as: Friel’s Zones 4-5a or Coggan’s Zone 4

Z5 – “Uncomfortably Hard” (VO2max) Zone

Uncomfortably hard mouth-breathing effort. You may be able to say a single, short word, but only if you have to. Breathing rate is rapid with short, forceful breaths.

  • Intensity: At your VO2max
  • Heart Rate: 103-106% of lactate threshold heart rate (LTHR)
  • Power: 106-120% of functional threshold power (FTPw)
  • Pace: 90-96% of functional threshold pace (FTPa)
  • Purpose: Used to increase the maximal rate of oxygen transport (aerobic capacity or VO2max), build lactate tolerance, and increase anaerobic endurance.
  • Also known as: Friel’s Zone 5b or Coggan’s Zone 5

Z6 – “Uncomfortably Hard” (Anaerobic Capacity) Zone

Uncomfortably hard mouth-breathing effort. You may be able to say a single, short word, but only if you have to. Breathing rate is rapid with short, forceful breaths. 

  • Intensity: Above your VO2max for short “speed” intervals less than 1-2 minutes
  • Heart Rate: Greater than 106% of lactate threshold heart rate (LTHR)
  • Power: Greater than 120% of functional threshold power (FTPw)
  • Pace: Faster than 89% of functional threshold pace (FTPa)
  • Purpose: Used to work on top-end speed and develop anaerobic capacity for short sprints less than 1-2 minutes in duration. 
  • Also known as: Friel’s Zone 5c or Coggan’s Zone 6

How the Alp Fitness Zones Compare to Other Systems

For those interested in how these zones relate to other training zone systems and where the percentages come from, here’s more background. 

The percentages of heart rate and pace come from Joe Friel’s seven-zone system, adapted to the Alp Fitness training zones; and the percentages of power come from Andrew Coggan’s six-zone system, adapted to the Alp Fitness training zones. 

The Alp Fitness zones are effectively Coggan’s first six zones with descriptive names added. In both Coggan’s zones and the Alp Fitness zones, Friel’s “Zone 4” and “Zone 5a” are merged into a single zone. Coggan calls this “Zone 4,” or the “threshold” zone. This is the same as the Alp Fitness “comfortably hard (high) zone.”

Updated on February 5, 2025

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