50–60%

Relaxed, easy pace, rhythmic breathing

Beginning-level aerobic training, reduces stress

60–70%

Comfortable pace, slightly deeper breathing, conversation possible

Basic cardiovascular training, good recovery pace

70–80%

Moderate pace, more difficult to hold conversation

Improved aerobic capacity, optimal cardiovascular training

80–90%

Fast pace and a bit uncomfortable, breathing forceful

Improved anaerobic capacity and threshold, improved speed

90–100%

Sprinting pace, unsustainable for long period of time, labored breathing

Anaerobic and muscular endurance, increased power