Does Cardio Ruin Your Muscle Gains?
Key insights: 60-second read
- Cardio does not appear to reduce muscle growth or maximal strength - this meta-analysis of 43 studies found no significant interference for either outcome.
- Explosive strength is different - cardio and strength training were associated with a small reduction in explosive strength, particularly when both were performed in the same session.
- Session timing may matter - when cardio and strength sessions were separated by at least 3 hours, significant interference with explosive strength was not observed.
- The findings were broadly consistent across groups - including different ages, training statuses and types of aerobic exercise studied.
- For most people, combining cardio and strength training is a sensible approach - the potential effect on explosive strength needs to be weighed against the broader benefits of being physically active.
If you do both cardio and strength training, you may have wondered whether one is impacting the results of the other.
A systematic review and meta-analysis published in Sports Medicine examined this idea across 43 studies involving more than 1,000 healthy adults. The overall findings are reassuring for most people, although explosive strength appears to be a little more sensitive to how cardio and strength training are combined.
So, can you do cardio and weights together without compromising your gains? Let's look at what the research found and what it may mean for your training.
On this page
What is the interference effect?
The interference effect refers to the concern that combining aerobic and strength training might reduce the adaptations you get from either type of training.
Aerobic training can improve cardiovascular fitness and metabolic health, while resistance training helps develop muscle mass, maximal strength and power. Because these forms of exercise place different demands on the body, it's interesting to consider whether doing both close together can compromise the results from either one.
The important question is not simply whether cardio and strength training can be combined, but whether the way they are combined affects particular outcomes such as muscle growth, maximal strength or explosive power.
How was the study conducted?
Study details
- Participants: 1,090 healthy adults, including 590 performing concurrent training and 500 performing strength training alone.
- Studies included: 43 studies published up to March 2021.
- Training: Supervised concurrent aerobic and strength training for at least 4 weeks.
- Comparison: The same strength training prescription without aerobic training.
- Outcomes: Maximal strength, explosive strength and muscle hypertrophy.
Cycling was the most common form of aerobic training, appearing in 24 studies, followed by running in 16 studies. The mean PEDro quality score was 4.3/10, suggesting the overall methodological quality wasn't overly strong.
Does cardio affect muscle growth and strength?
Does cardio reduce maximal strength?
Based on 37 studies involving 967 participants, the analysis found no significant interference from aerobic training on maximal strength development.
In practical terms, adding cardio to a resistance training program did not appear to meaningfully reduce improvements in maximal strength in the populations studied.
Does cardio reduce explosive strength?
This is where the findings were a little more nuanced. Across 18 studies involving 478 participants, concurrent training was associated with a meaningful reduction in explosive strength.
Does separating cardio and weights make a difference?
The timing of the sessions appeared to matter for explosive strength. When aerobic and strength training were performed within the same session, the interference effect was meaningful. When sessions were separated by at least 3 hours, meaningful interference was not observed. This suggests that separating sessions may be useful when explosive strength or power is a major training priority.
Does cardio reduce muscle growth?
Across 15 studies involving 389 participants, the analysis found no significant interference with muscle hypertrophy.
Key finding: In this meta-analysis, combining aerobic and strength training did not significantly compromise muscle growth or maximal strength. The main concern was explosive strength, particularly when cardio and strength training were performed in the same session.
What does this mean for your training?
For most people, there is little reason to avoid cardio because you are trying to build muscle or get stronger. The research suggests that you can combine both forms of training without meaningfully compromising muscle growth or maximal strength.
- If muscle growth is your priority: The evidence does not suggest that adding cardio will automatically compromise hypertrophy.
- If maximal strength is your priority: Combining cardio and strength training did not significantly reduce maximal strength in this analysis.
- If explosive power is your priority: Consider separating cardio and strength sessions by at least 3 hours, or performing them on different days.
- If general health and fitness are your priority: There is a strong practical case for including both aerobic and resistance training rather than avoiding one because of concerns about interference.
- If you are choosing between cycling and running: This review did not identify a meaningful difference between the two, although the findings cannot automatically be applied to every form of cardio.
- Remember the bigger picture: Training volume, recovery, nutrition, sleep, and your overall program still matter. The interference effect is only one part of the training equation.
For most recreational exercisers, the practical message is reassuring: you do not necessarily have to choose between cardiovascular fitness and getting stronger.
What are the limitations of the research?
The findings are useful, but they should not be interpreted as proof that every combination of cardio and strength training will produce identical results. The authors identified several limitations.
- Moderate overall evidence quality: The mean PEDro score was 4.3/10, which wasn't great, and seven included studies were classified as low quality.
- Blinding limitations: Blinding participants is difficult in exercise research, which can affect methodological quality.
- Limited information about aerobic intensity: The studies did not provide sufficiently consistent information to properly examine whether cardio intensity influenced the results.
- Some self-reported measures: Self-report can introduce measurement bias.
From a practical perspective, this research is reassuring. For most people, combining aerobic and strength training is unlikely to undermine muscle growth or maximal strength.
- Muscle growth and maximal strength were not significantly compromised by adding aerobic training.
- Explosive strength may be more sensitive to concurrent training, particularly when cardio and weights are performed in the same session.
- Separating sessions by at least 3 hours may help when explosive strength or power is a key goal.
If your goal is general health and fitness, I would not let concerns about the interference effect stop you from doing cardio. If you are training specifically for power or explosive performance, however, the timing and structure of your sessions may deserve more attention.
- Grant
Frequently Asked Questions
Does cardio kill your gains?
Not according to this meta-analysis. Adding aerobic training to a strength program did not significantly compromise muscle growth or maximal strength. However, explosive strength was more likely to be affected, particularly when cardio and strength training were performed in the same session.
Can I do cardio and weights on the same day?
Yes. The research suggests that combining cardio and strength training is generally compatible with improvements in muscle growth and maximal strength. If explosive power is a major priority, separating the sessions may be preferable.
Should I do cardio before or after weights?
This study did not identify a significant order effect. The more important finding was that explosive strength may be affected when cardio and strength training are performed in the same session. If power is a priority, separating the sessions by at least 3 hours may be useful.
How many hours should I separate cardio and strength training?
The analysis found no significant interference with explosive strength when aerobic and strength sessions were separated by at least 3 hours. This does not mean 3 hours is a universal rule, but it is a useful practical consideration if explosive strength is important to your training.
Does cardio reduce muscle growth?
This meta-analysis found no significant reduction in muscle hypertrophy when aerobic and strength training were combined. Individual results can still vary depending on training volume, intensity, recovery and other factors.
Does the type of cardio matter?
The review found no significant difference between cycling and running in the outcomes examined. Other forms of aerobic training were not represented in sufficient numbers to draw the same conclusion.
One key insight from this research
Combining aerobic and strength training did not significantly compromise muscle hypertrophy or maximal strength in this meta-analysis. Explosive strength was more likely to be affected, particularly when aerobic and strength training were performed in the same session.
Reference
Schumann, M., Feuerbacher, J. F., Sünkeler, M., Freitag, N., Rønnestad, B. R., Doma, K., & Lundberg, T. R. (2022). Compatibility of Concurrent Aerobic and Strength Training for Skeletal Muscle Size and Function: An Updated Systematic Review and Meta-Analysis. Sports Medicine, 52(3), 601-612. https://doi.org/10.1007/s40279-021-01587-7
Need personalised guidance for your training?
If you would like help managing an injury or addressing any musculoskeletal issue, you can book with Grant either in Port Macquarie or via an online telehealth consultation.
