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Can Strength Training Replace Cardio? A Look Into The Research

Author: Ava Durgin

May 08, 2026

Assistant Health Editor

By Ava Durgin

Assistant Health Editor

Ava Durgin is the former Assistant Health Editor at mindbodygreen. She holds a B.A. in Global Health and Psychology from Duke University.

Image by Studio Firma/Stocksy / mbg creative

May 08, 2026

You've just finished a brutal set of squats. Your heart is hammering, you're dripping sweat, and your lungs are burning. It feels exactly like a cardio workout, so why would you need to hop on the treadmill afterward?

It's one of the most common questions in the fitness world, and honestly, it makes total sense to ask it.

But the short answer is no, strength training doesn't replace cardio—not fully, anyway. But the longer answer is a lot more interesting, and understanding it could change how you structure your fitness routine.

Two workouts, two different demands on the heart

At a glance, lifting and cardio can feel similar in terms of movement, effort, and intensity. But the physiological stress they create is distinct.

When you go for a run, hop on a bike, or take a brisk incline walk, your muscles need a continuous supply of oxygen. Your heart responds by pumping more blood per minute. Your lungs increase oxygen exchange. Your blood vessels dilate to improve flow. This demand is steady and sustained.

Over time, this kind of training leads to classic aerobic adaptations1:

- An increase in stroke volume (the amount of blood your heart pumps per beat)

- Greater mitochondrial density in muscle cells

- Expanded capillary networks for improved oxygen delivery

- A higher VO2 max, the maximum amount of oxygen your body can use during exercise

VO2 max, in particular, is one of the strongest predictors of longevity we have. Higher cardiorespiratory fitness is consistently linked to lower risk of cardiovascular disease and all-cause mortality.

Resistance training creates a different stimulus.

When you lift a heavy weight, effort is intense but brief. Muscles contract forcefully, temporarily compressing blood vessels. Blood pressure spikes during the lift. Your heart rate rises, but often in short bursts, followed by rest between sets.

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Instead of a sustained oxygen demand, you’re creating intermittent stress. Much of the energy used during heavy lifting comes from anaerobic systems, meaning they don’t rely primarily on oxygen.

The primary adaptations here include:

- Increased muscle fiber size and strength

- Improved neuromuscular efficiency

- Greater bone density

- Enhanced glucose storage and insulin sensitivity

Your cardiovascular system is absolutely involved. It’s just not being trained in the same sustained, oxygen-driven way.

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A high heart rate doesn’t automatically equal cardio

This is where the misconception tends to take hold.

Heart rate is an easy metric to see and track. When it spikes during lifting, it feels like proof that you’re doing cardio.

But heart rate alone doesn’t tell the whole story.

During aerobic exercise, your heart rate stays elevated for an extended period, often 20, 30, or 45 minutes continuously. That sustained elevation forces your heart to adapt by becoming more efficient at pumping blood. It also trains your muscles to extract and utilize oxygen more effectively.

During strength training, heart rate typically rises during a set and drops during rest. Even in circuit-style workouts, the cumulative time spent at a steady aerobic threshold is often lower than during a dedicated cardio session.

In other words, the pattern of stress matters just as much as the intensity.

Research comparing resistance training to aerobic training consistently shows that while both improve overall health markers, aerobic exercise produces greater improvements2 in VO2 max and cardiorespiratory endurance.

And that distinction is important. Cardiorespiratory fitness isn’t just about performance; it’s tightly tied to heart health and longevity.

What strength training does for your heart (that cardio doesn’t)

Before you feel defensive about your lifting routine, let's be clear: resistance training is excellent for cardiovascular health. It just works through different mechanisms than you might expect.

For one, lifting is particularly effective at improving insulin sensitivity. Skeletal muscle is a major site of glucose storage. When you build muscle, you increase your body’s capacity to handle blood sugar efficiently, reducing metabolic strain and lowering risk for type 2 diabetes and heart disease.

Resistance training is also associated with reductions in resting blood pressure over time. While blood pressure may spike during a lift, chronic adaptations can improve vascular function and reduce baseline readings.

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