Cardio or Resistance Training: Which should I do?

If you've ever stood in a gym wondering whether to hop on the bike or load up a barbell, you're not alone. It's one of the most common questions in fitness, and the honest answer isn't as simple as picking a side. Cardio and resistance training do different jobs in your body, and the research increasingly points to the same conclusion: you need both.

Here's how to think about it.



What cardio does best

Aerobic exercise, running, cycling, rowing, swimming, or anything that gets your heart rate up for a sustained stretch, is the most direct way to build cardiovascular fitness. It strengthens your heart and lungs, improves circulation, and lowers your risk of heart disease. A 20-year cohort study (the ATTICA study) found that consistent aerobic activity was strongly linked to lower cardiovascular disease incidence over time.

Cardio is also efficient for burning calories during the workout itself, which is why it's often the first thing people reach for when the goal is weight loss.

What resistance training does best

Lifting weights builds and preserves muscle, and that matters more than most people realize, especially if the goal is fat loss. Muscle is metabolically active tissue: the more you have, the more calories your body burns at rest. Research comparing resistance training to aerobic-only training found that lifters lost more body fat while aerobic-only groups tended to lose fat and muscle together, since some of the weight lost wasn't fat at all.

Resistance training also protects against age-related muscle loss, supports bone density, and improves everyday strength and mobility. A 2026 study in the British Journal of Sports Medicine found that just two to four hours of strength training a week was associated with meaningfully lower all-cause mortality, with benefits leveling off around two hours weekly.

The real answer: it's not either/or

The strongest evidence doesn't crown a winner. It shows that combining both delivers better outcomes than either one alone. One meta-analysis found resistance training alone was associated with a 21 percent lower all-cause mortality risk, and combining it with aerobic exercise pushed that number to 40 percent.

The CDC and American College of Sports Medicine guidelines reflect this. The recommendation for adults is:

• 150 minutes of moderate aerobic activity a week (or 75 minutes of vigorous activity)
• At least 2 days a week of muscle-strengthening work covering all major muscle groups

That's the baseline, not the ceiling, but it's a useful target if you're building a routine from scratch.

How to actually balance it

A simple, sustainable split for most people:

• 2 to 3 strength sessions a week, focused on major movement patterns like squats, hinges, presses, and pulls
• 2 to 3 cardio sessions a week, mixing steady-state (a long walk, an easy bike ride) with something higher intensity when recovery allows
• At least one full rest or active recovery day

The order and intensity can flex depending on your goals. Training for a race? Cardio takes priority, with strength work supporting durability. Training for strength or body composition? Lifting comes first, with cardio supporting heart health and recovery.

Why this matters beyond the workout

Consistency, not perfection, is what makes any program work. That's true for members trying to build a habit, and it's true for the gyms coaching them. When a gym can show a member their strength numbers climbing alongside their cardio conditioning, in one place, it reinforces that progress is happening on both fronts, not just one. That kind of visibility (tracked PRs, benchmark workouts, attendance trends across class types) tends to be what keeps someone showing up six months in, not just six weeks in.

The takeaway: skip the debate. Program both, track both, and let the data show your members they're getting stronger and healthier at the same time.

Sources:

• Comparison of concurrent, resistance, or aerobic training on body fat loss: a systematic review and meta-analysis
• Assessment of Long-Term Engagement in Aerobic Versus Resistance Exercise on 20-Year Cardiovascular Disease Incidence: The ATTICA Epidemiological Cohort Study
• ACSM Unveils Landmark 2026 Resistance Training Guidelines
• CDC: Adult Activity, An Overview
• ScienceDaily: Scientists found the strength training sweet spot for a longer life