Not all cardio is created equal. Whether you're walking, jogging, cycling, or doing intervals, the intensity you're working at changes what your body gets out of it (remember SAID principle). Understanding heart rate zones helps you train with more purpose.

Here’s a breakdown of the 5 main cardio zones and what they actually do for your health, performance, and longevity.

Zone 1 – Recovery & Circulation (50–60% Max HR)

Think: Easy walking, mobility circuits, active recovery days

• Helps with blood flow, joint health, and recovery

• Good for reducing stress and getting movement without fatigue

• Supports heart health by improving your ability to relax and recover

Best used for: Rest days, low-stress movement, pre/post workout recovery

Zone 2 – Fat Burning & Endurance (60–70% Max HR)

Think: Brisk walking, light jogging, long steady rides

• Trains your body to burn fat more efficiently

• Builds your aerobic base, essential for heart health and stamina

• Improves how much blood your heart pumps per beat (stroke volume)

Best used for: Longevity, fat loss, building sustainable cardio fitness

*This is where most people should be spending time if their goal is long-term health and body composition.

Zone 3 – Aerobic Threshold (70–80% Max HR)

Think: Tempo runs, moderate but steady effort

• Mixes fat and carbs for fuel

• Trains your body to handle more intensity without gassing out

• Improves your ability to clear and tolerate lactic acid

Best used for: Improving performance/stamina, preparing for sport or longer races

*This zone can be too hard for easy days.

Zone 4 – High Intensity / VO₂ Max Training (80–90% Max HR)

Think: Hard intervals, hill sprints, intense spin sessions

• Boosts performance and increases your oxygen capacity

• Teaches your body to work harder & longer

• Pushes your heart and lungs close to their max output

Best used for: Athletic training, HIIT, or breaking through plateaus

Zone 5 – Max Effort (90–100% Max HR)

Think: All-out sprints, explosive efforts, competitive events

• Builds speed and peak power

• Sharpens coordination and explosiveness

• Demands full recovery - this is not everyday training

Best used for: Advanced athletes, short bursts, performance peaks

*This zone is not for beginners or casual training. It’s stressful, and likely needs its own recovery timeline.

So… Which Zone Should You Be Training In?

Like everything else in training, it depends on your goal.

For most who want overall body recomposition and longevity - Stick to Zone 2 most of the time

Want to improve your performance or training for specific sport? Add in Zone 3–4

Use Zone 5 sparingly and strategically to push yourself to the limits.

Knowing when to go easy, when to push, and why it matters will take your training to another level.