All about Zone 2 cardio

Assessed by Brian St. Pierre, MS, RD

“Cargo pants are making a comeback.”

(St. Pierre, a father, learned this through his 12-year-old daughter.)

Cardio is back in the spotlight.

zone 2 cardio—also referred to as steady state cardio, low intensity steady state cardio (LISS), or what your treadmill might label as the “fat burning zone” (we’ll delve into this term later).

• What zone 2 cardio entails (and how to recognize when you’re “in it”)
• How much zone 2 cardio you should aim for each week to reap the health and fitness benefits
• How zone 2 cardio compares to other exercise forms
• The potential drawbacks of zone 2 cardio—and how to address them

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What exactly is “zone 2 cardio”?

Zone 2 cardio involves sub-maximal aerobic training—essentially, aerobic exercise performed below your maximum capacity.

Examples of Zone 2 cardio

• Leisurely biking
• Utilizing the elliptical machine
• Hiking or walking uphill
• Rucking (walking with a weighted backpack or vest)
• Gentle jogging on level ground
• Rowing (using a machine or, if available, a canoe on a tranquil lake)

Zone 2 cardio versus other cardiovascular “zones”

*Exercise intensity is the primary factor determining the energy source utilized during exercise. However, several factors—such as exercise duration, age, gender, body composition, fitness level, and diet—can influence the proportion of energy sources utilized.

Three key benefits of zone 2 cardio

Benefit #1: It establishes your aerobic foundation.

metabolic flexibility⁴—and zone 2 cardio is particularly effective at enhancing it.

and performance.

Benefit #2: It offers more benefits than drawbacks.

aid in your recovery between sessions,” notes St. Pierre. “At the very least, it will not add excessive stress or necessitate recovery to the same extent as interval training would.”

Benefit #3: It enhances mitochondrial health—potentially improving longevity and quality of life.

5

6 (though studies supporting this involve participants engaging in substantial hours of zone 2 work weekly).

all forms of physical activity—including interval and resistance training—support and enhance mitochondrial health.^{7 8 9}

“How can I determine if I’m in zone 2?”

Method #1: Tracking devices

10)

Method #2: Mathematical calculation

Method #3: Body awareness

• You are engaged in cardio that requires effort yet feels sustainable for an extended period
• You can breathe through your nose
• You can converse (albeit not sing fluently)
• You can concentrate on a podcast, movie, or hold a meaningful conversation

TL;DR: Zone 2 work should not overwhelm you.

How much zone 2 cardio should you aim for weekly?

As much as you can accommodate.

11 12

How long should zone 2 cardio sessions last?

total, it is not futile.