LISS vs HIIT vs Zone 2: Cardio Types Explained

The different kinds of cardio and when to use each.

Cardio
Olivia ParkRun coaching & endurance·July 1, 2026·6 min read

"Cardio" isn't one thing. The intensity you choose changes the adaptation you get — and the recovery cost you pay. Here's how the main types differ and how to blend them.

LISS — low-intensity steady state

Think brisk walking or an easy bike. Low cost, easy to recover from, great for building volume and burning calories without frying you. The backbone of most fat-loss plans.

Zone 2 — the aerobic base

A conversational pace you can hold for 30–60 minutes. It builds mitochondrial density and aerobic efficiency — the engine that makes everything else easier. Aim for a pace where you can still talk in full sentences.

HIIT — high-intensity intervals

Short, hard efforts with recovery between. Time-efficient and potent for conditioning, but expensive to recover from. Two or three sessions a week is plenty for most people.

Key takeaways

  • LISS builds volume cheaply.
  • Zone 2 builds your aerobic engine.
  • HIIT is potent but costly — cap it at 2–3x/week.
  • Most people do best blending all three.
Education, not medical advice. GymGuide provides general fitness guidance to help you understand your options. It does not diagnose, treat, or replace care from a physician or physical therapist. Progress gradually, and stop if anything causes pain. You can modify or decline any recommendation.

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