Resistance Training Can Raise VO2peak After 60—With Limits

Resistance training can improve cardiorespiratory fitness after age 60. That matters because better fitness supports walking, climbing stairs, and living independently—not merely looking more competent around a dumbbell rack. But weights are not the same as aerobic training for building long-term aerobic capacity, and the popular claim that lifting works by building mitochondria has outrun the human evidence.

The practical answer is less tribal than the usual cardio-versus-weights argument: use resistance training, but pair it with aerobic work if cardiorespiratory fitness is a priority.

Weights improve fitness, not only strength

A 2022 systematic review and meta-analysis by Smart et al. examined 37 randomized controlled trials of resistance exercise training in healthy older adults. Across 22 trials reporting VO2peak, programs lasting 24 weeks or less increased VO2peak by an average of 1.89 mL/kg/min (95% CI, 1.21 to 2.57). VO2peak measures the highest rate at which the body uses oxygen during exercise; it is a standard measure of cardiorespiratory fitness.

The same analysis found a 30.89-meter improvement in the six-minute walk test (95% CI, 26.70 to 35.08; I²=0%) and an aerobic-threshold increase of 1.27 mL/kg/min (95% CI, 0.44 to 2.09) across four trials. A higher aerobic threshold means a person can do more work before lactate begins accumulating rapidly. For older adults, that can make ordinary movement feel less taxing. The threshold result is promising, but four trials are not enough to treat it as settled.

A newer 2025 meta-analysis by Azimkhani et al. reached the broader conclusion that aerobic, resistance, and combined exercise all improve fitness in healthy people 60 and older. It pooled 51 randomized trials involving 3,152 participants and reported an overall standardized mean difference of 0.51 for VO2max or VO2peak (95% CI, 0.38 to 0.65; p<.001), plus a 36.18-meter gain in six-minute walk distance (95% CI, 26.52 to 45.84; p<.001). Those pooled estimates combine exercise modalities, so they confirm that exercise works; they do not prove that each modality produces the same effect.

The apparent six-month ceiling

The most useful detail in the resistance-training analysis is the timeline. Within 24 weeks, VO2peak rose. In studies lasting longer than 24 weeks, the pooled change was -0.01 mL/kg/min (95% CI, -1.19 to 1.17; I²=0%). That estimate includes no meaningful average increase and no statistically reliable difference from zero.

Smart et al. also found that intervention length did not predict VO2peak change in meta-regression (R²=2%; P=0.42). This supports an apparent group-level plateau, but it does not establish a biological stop sign at week 25. Long-term trial evidence may be limited, and pooled averages can hide sharply different individual responses.

That concern has data behind it. An ancillary meta-analysis by Kelley et al. in 2024, using 22 randomized trials, found true inter-individual differences in cardiorespiratory response to resistance training that exceeded measurement error. Some people likely gain far more than the average, while others gain little. Periodic fitness testing can therefore be more informative than treating a pooled estimate as a personal forecast.

The 1.89 mL/kg/min average gain also falls below the conventional approximation of one metabolic equivalent, about 3.5 mL/kg/min, often used in population-level discussions of fitness and survival. That comparison does not make the gain meaningless. A modest change may matter more to a deconditioned person with low starting fitness than to someone already fit. The available pooled data cannot settle that individual clinical question.

Aerobic training remains the main engine for CRF

Aerobic exercise generally produces larger cardiorespiratory-fitness gains when modalities are compared, especially at higher intensities. A 2024 systematic review and meta-analysis by Fosstveit et al. found that higher-intensity aerobic training produced larger VO2max gains than moderate-intensity training in older adults. The evidence does not provide an equivalent dose-response map for resistance-training load or weekly frequency, so no one can honestly prescribe a minimum lifting dose for VO2peak improvement from these findings.

Combined programs offer a sensible way to avoid making the modalities compete for a job neither fully covers. In the 2025 cross-modal analysis, combined training retained benefits in longer-than-24-week subgroups. That pattern fits, but does not prove, the idea that the aerobic component continues to drive cardiorespiratory adaptation after resistance training's average contribution has leveled off.

For adults over 60, resistance training can build some cardiorespiratory fitness. Aerobic training remains the better-supported choice for maximizing it over time.

The mitochondrial story does not belong to lifting—yet

Exercise can improve mitochondrial features in older muscle, but the modality matters. A 2026 systematic review and meta-analysis by Vabishchevich et al. reported that moderate-intensity continuous aerobic training induces mitochondrial adaptations that include greater elongation and density, higher enzyme activity, biogenesis, and mitophagy. A 2022 systematic review by Lippi et al. also framed exercise as a possible intervention for age-related mitochondrial decline, while examining endurance, resistance, and combined exercise in older adults.

But a general exercise finding is not proof that resistance training produces the same cellular changes. The sharper test came from a 2023 randomized head-to-head trial by Ruegsegger et al. in healthy sedentary younger and older adults. High-intensity aerobic training significantly improved skeletal-muscle mitochondrial dynamics. Resistance training and combined training did not produce equivalent mitochondrial improvements.

That result does not erase resistance training's VO2peak benefit. It does mean the familiar explanation—lifting improves aerobic fitness because it builds mitochondria in the same way endurance exercise does—lacks direct support here. No study in this evidence base quantified before-and-after changes in markers such as PGC-1α, citrate synthase, mitochondrial DNA copy number, cristae density, or respiratory-complex activity after chronic resistance training specifically in adults 60 and older. The mechanism remains unresolved.

What to do with this evidence

Lift if you enjoy lifting, need a lower-impact option, or want the muscular and skeletal benefits that aerobic exercise does not fully reproduce. Expect that a well-run resistance program may also improve VO2peak and walking endurance during its first several months.

If your main goal is continued cardiorespiratory improvement, add aerobic training rather than assuming more months of isolated lifting will keep moving VO2peak upward. Higher-intensity aerobic work has the strongest evidence for larger VO2max gains in older adults, but the right intensity depends on fitness, health status, injuries, and supervision needs.

The evidence supports combination, not a winner-take-all workout identity. Resistance training earns a place in an older adult's fitness plan. Aerobic training remains the better-tested tool for sustained CRF gains and mitochondrial remodeling, while the route from lifting to better VO2peak is still an open scientific question.