Does Strength Training Improve VO2 Max?

# Does Strength Training Improve VO2 Max?

If you love lifting weights but are less enthusiastic about cardio, you may have wondered whether your time under the bar is doing anything for your cardiovascular fitness. The relationship between strength training and VO2 max is more nuanced than a simple yes or no. Here is what the evidence actually shows.

The Short Answer

Strength training can improve VO2 max in untrained or sedentary individuals, but the improvements are modest compared to dedicated aerobic training. In already fit or aerobically trained people, strength training alone does not meaningfully increase VO2 max. If maximal aerobic capacity is your goal, you need to include some form of cardiovascular training.

What the Research Shows

In Untrained Populations

For people who have been sedentary, almost any form of structured exercise will initially improve VO2 max. The body is responding to a novel stimulus, and the cardiovascular system adapts to meet the new demands. Studies have shown that resistance training programs in previously sedentary adults can improve VO2 max by 5 to 8 percent over 8 to 12 weeks.

This makes sense physiologically. Heavy resistance training elevates heart rate, sometimes substantially during high-rep sets or compound movements. For someone whose cardiovascular system is untrained, this stimulus is sufficient to drive adaptations in cardiac output and peripheral oxygen extraction.

In Trained Individuals

For people who are already aerobically fit, strength training has minimal impact on VO2 max. A meta-analysis examining the effects of resistance training on VO2 max in healthy adults found that improvements were largely confined to untrained subjects. Trained individuals showed negligible changes.

The reason is that the cardiovascular demands of traditional strength training, while real, are not sustained at the intensities and durations needed to push the ceiling of maximal oxygen uptake. A set of heavy squats elevates heart rate dramatically, but the set lasts 20 to 40 seconds followed by several minutes of rest. The total time spent at high cardiovascular demand during a typical strength session is relatively small.

Circuit Training: A Special Case

Circuit-style resistance training with short rest periods and higher repetition ranges does produce more sustained cardiovascular demand. Studies on circuit training have shown VO2 max improvements of 8 to 12 percent, which approaches the lower end of what dedicated aerobic training can achieve.

However, circuit training involves significant compromises in strength development. The loads used are necessarily lighter, the rest periods are insufficient for full neuromuscular recovery, and the overall strength stimulus is reduced. You end up with a training stimulus that is suboptimal for both strength and cardiovascular fitness compared to doing each separately.

How Strength Training Supports Cardiovascular Fitness Indirectly

Even though pumping iron is not the most efficient path to a higher VO2 max, it supports cardiovascular fitness in several important ways.

Improved Movement Economy

Stronger muscles are more efficient muscles. Research has shown that strength training improves running economy (the oxygen cost of running at a given pace) in endurance athletes. Better economy means you can run faster or longer at the same VO2, effectively making your existing aerobic capacity more useful.

Greater Work Capacity

Muscular strength and endurance allow you to sustain higher workloads during cardiovascular training. A lifter with a strong posterior chain can maintain proper running form longer. Strong legs produce more power on the bike. A robust core stabilizes you during rowing. All of this enables higher-quality cardio sessions that more effectively stimulate VO2 max adaptations.

Injury Prevention

One of the biggest threats to cardiovascular fitness is interruption in training due to injury. Strength training builds resilient connective tissues, corrects muscular imbalances, and improves joint stability. Staying healthy and training consistently does more for long-term VO2 max than any single workout protocol.

Body Composition Effects

Strength training helps build and maintain lean mass while reducing body fat. Since VO2 max is expressed relative to body weight, improving body composition (more muscle, less fat) can improve your mL/kg/min value even without direct cardiovascular adaptations.

Cardiovascular Structural Adaptations

Heavy resistance training does produce some cardiovascular structural changes. Studies using echocardiography have shown that strength athletes develop concentric cardiac hypertrophy (thicker heart walls), which differs from the eccentric hypertrophy (larger heart chambers) seen in endurance athletes. While concentric hypertrophy does not increase stroke volume the way eccentric hypertrophy does, it does indicate that the heart is adapting to the pressure demands of heavy lifting.

The Practical Takeaway for Lifters

If you are a strength athlete or someone who primarily trains with weights, here is the honest assessment.

Your lifting is not doing nothing for your cardiovascular system. It is providing a baseline stimulus, maintaining some aerobic function, and supporting all the indirect factors mentioned above. But it is not a substitute for actual cardiovascular training when it comes to VO2 max.

The good news is that you do not need enormous volumes of cardio to see meaningful VO2 max improvements. Research suggests that as little as two to three sessions per week of moderate-intensity aerobic training (30 to 45 minutes each) can produce significant VO2 max gains in people who were previously doing no cardio. Add one weekly session of high-intensity intervals, and you have a robust cardiovascular training program that fits alongside a full lifting schedule.

Practical Ways to Add Cardio Without Losing Gains

The fear of losing muscle or strength from cardio is overblown for most recreational lifters when cardio is programmed intelligently.

Walk daily. Aim for 8,000 to 10,000 steps. This builds an aerobic base with zero interference to strength training.

Use low-impact modalities. Cycling, rowing, and the elliptical produce less muscle damage than running, which means less interference with recovery from lifting.

Separate sessions when possible. If you can do cardio and lifting in separate sessions or on separate days, the interference effect is minimized. If you must combine them, do your lifting first and cardio second.

Start small and build. If you are currently doing zero cardio, start with two 20-minute Zone 2 sessions per week and build from there. Even this modest addition will move the needle.

Use conditioning work. Sled pushes, loaded carries, battle ropes, and kettlebell complexes provide a cardiovascular stimulus with a resistance component. These are not pure VO2 max training, but they bridge the gap between lifting and cardio.

The Bottom Line

Strength training alone is not an effective strategy for maximizing VO2 max, especially if you are already physically active. However, it is a powerful complement to cardiovascular training and supports aerobic fitness through multiple indirect pathways. The ideal approach for health, longevity, and performance combines dedicated strength training with purposeful cardiovascular work. Neither is a substitute for the other, and both deserve a place in your program.