LISS (Low-Intensity Steady State)

LISS is continuous aerobic exercise performed at a low, comfortable intensity that can be held for an extended period (commonly 30–60 minutes or more). The intensity sits roughly in the light range — about 57–63% of maximal heart rate, 30–40% of heart-rate reserve, or RPE 9–11 on the Borg 6–20 scale (well within the "talk test" comfort zone, where full sentences are easy). It overlaps with the lower end of zone 1–2 work (see Heart-Rate Zones (5-Zone Model)).

Typical LISS modalities are walking, easy cycling, light elliptical, or slow swimming. Because the effort is low and almost entirely aerobic, it produces little fatigue, minimal joint stress, and fast recovery — which makes it ideal for deconditioned beginners, for active recovery between hard days (see Recovery Cardio (Active Recovery)), and as a high-volume, low-risk way to accumulate energy expenditure for fat-loss programs.

Note on fat loss: low intensity burns a higher percentage of calories from fat, but total calories burned (which depends on duration and total work) is what governs weight change — not the fuel mix. See Fat-Burning Intensity (Low- vs. High-Intensity Cardio) for the full accounting; do not over-credit LISS for "fat burning" on a per-minute basis.

LISS differs from zone-2 training mainly by precision: zone 2 is pinned just below the first lactate threshold for a specific metabolic adaptation, whereas LISS is a looser "keep it easy" prescription (see Zone 2 Training).

• Low intensity: ~57–63% HRmax, ~30–40% HRR, RPE ~9–11 (Borg 6–20); easy talk-test pass.
• Continuous, typically 30–60+ minutes; sustainable and low-fatigue.
• Modalities: walking, easy cycling, light elliptical, slow swim.
• Best for beginners, active recovery, and high-volume calorie accumulation.
• Higher percent fat oxidation, but total calories — not fuel mix — drive fat loss.