Does Strength Training Improve VO2max as Much as Cardio?
Two different training styles, the same outcome measured directly against each other, in the same pool of randomized trials.
This piece covers a systematic review and meta-analysis of randomized controlled trials comparing aerobic training against resistance training for VO2max/peak and body composition outcomes, specifically in middle-aged to older adults. It does not cover younger adult or athlete populations, and it does not cover combined aerobic-plus-resistance programs, which the underlying trials tested as separate arms rather than a blended protocol.
Aerobic training and resistance training are often treated as interchangeable ways to improve general fitness, but they are not equally effective for every outcome. A pooled analysis of randomized controlled trials in middle-aged and older adults compared the two training styles directly against each other, rather than against a no-exercise control, and found aerobic training produced a meaningfully larger improvement in VO2max/peak and walking capacity. Resistance training, in the same pooled trials, came out ahead on a different outcome entirely: preserving and building lean body mass. Neither style beat the other outright, detailed with exact figures below, they were simply better at different things.
A head-to-head comparison, not two separate reviews
Most of what's cited on this site about VO2max compares a training method against doing nothing, or against a different intensity of the same underlying activity. This is a narrower and arguably more useful comparison: aerobic training and resistance training, tested against each other inside the same randomized controlled trials, in the same pooled analysis, in the same population.
That population matters for who this applies to. The trials included here were conducted in middle-aged to older adults, not young athletes or general fitness populations, which is the group most likely to be weighing a real, practical tradeoff between cardio-style training and strength-style training rather than doing both without much thought.
1 study
- Pooling 38 RCTs (1,682 participants), aerobic training produced significantly greater improvement in VO2max/peak than resistance training (mean difference 1.80 mL/kg/min, 95% CI 0.96 to 2.64) and in six-minute walk distance (mean difference 18.58 meters, 95% CI 10.38 to 26.78), and produced a significantly greater decrease in body mass (mean difference -1.23 kg, 95% CI -1.98 to -0.47). Resistance training produced significantly greater gains in lean body mass than aerobic training. The VO2max/peak and walk-distance advantages for aerobic training held consistently across healthy and unhealthy participants, across men and women, across medium-term (under 24 weeks) and long-term (24 weeks or more) programs, and across adults aged 65 and under versus over 65.
Why the aerobic-training edge held up across so many subgroups
The consistency is the notable part here. It would be easy for a pooled result like this to be driven by one large subgroup, older participants doing longer programs, say, while a different subgroup showed no real difference. That's not what happened. The aerobic-training advantage for VO2max/peak and walk distance showed up whether participants were healthy or already managing a health condition, whether they were men or women, whether the program ran under six months or over it, and on both sides of a 65-year-old age split.
That consistency is what makes this a genuinely useful comparison rather than a single study result that might not generalize. It suggests the aerobic-versus-resistance difference in VO2max response is a real, structural feature of how each training style stresses the cardiorespiratory system, not an artifact of any one trial's specific participants or protocol.
This comparison is specific to aerobic training tested against resistance training as separate, distinct programs. It does not test a combined program that includes both in the same training week, which is how a lot of real-world exercise routines are actually structured. Whether a combined program captures both advantages, better VO2max from the aerobic component and better lean mass from the resistance component, or whether combining them dilutes either effect, is a different question than the one this meta-analysis answers.
Two different outcomes, not a winner and a loser
It's tempting to read a comparison like this as settling which training style is "better," but the actual result argues against that framing. Aerobic training won clearly on VO2max/peak, walk distance, and body mass reduction. Resistance training won clearly on lean body mass, an outcome with its own real, independent value for older adults specifically, where preserving muscle mass is tied to functional independence and fall risk in ways VO2max alone doesn't capture.
The practical read, grounded in what this pooled data actually shows rather than what either training camp tends to claim, is that the two styles are complementary rather than substitutable. Someone whose priority is cardiorespiratory fitness specifically has real, pooled evidence that aerobic training gets there more reliably. Someone prioritizing lean mass preservation has the mirror-image evidence for resistance training.
How this differs from the site's existing HIIT-vs-steady-state coverage
The existing HIIT vs. steady-state cardio for VO2max piece compares two aerobic training intensities against each other. This piece compares a different axis entirely: aerobic-style training against resistance-style (strength) training, a comparison of training modality rather than aerobic intensity.
Common questions
Does strength training improve VO2max as much as cardio?
No, according to a pooled analysis of 38 randomized trials in middle-aged to older adults. Aerobic training produced a significantly larger improvement in VO2max/peak than resistance training did, in the same trials, in the same population.
Is resistance training worthless for cardiorespiratory fitness then?
The pooled trials don't say resistance training does nothing for fitness, only that aerobic training outperformed it specifically on VO2max/peak and walking capacity. Resistance training had its own clear advantage in the same analysis: significantly greater gains in lean body mass.
Does this apply to younger adults or athletes?
This specific pooled analysis was conducted in middle-aged to older adults. Whether the same aerobic-versus-resistance pattern for VO2max holds in younger or already-trained athletic populations isn't what this meta-analysis tested.
What about doing both aerobic and resistance training together?
This meta-analysis compared aerobic and resistance training as separate program arms, not a combined program. It doesn't directly answer whether combining both in the same training week captures each style's individual advantage.