We had a great question come up in SGPT recently:
“Does doing cardio affect my ability to build muscle?”
The short answer?
It can, but it doesn’t have to.
Let’s break it down clearly: what the research says, how it applies in real life, and what to avoid if your goal is muscle growth.
The Science: Concurrent Training
There’s a term for mixing cardio and strength in the same programme: concurrent training.
Multiple studies and meta-analyses (Wilson et al., 2012; Schoenfeld et al., 2021) have looked at how aerobic exercise can influence strength, hypertrophy, and power development.
Schoenfeld et al. (2021) – The Effect of Aerobic Training on Muscle Growth
Meta-analysis: Looked at hypertrophy outcomes in concurrent training models (resistance + cardio).
Key finding:
"High-frequency, long-duration cardio can interfere with hypertrophy, especially when not spaced from resistance sessions.
However, moderate cardio, performed 6+ hours apart, does not significantly blunt muscle gains."
For those looking to include cardio while training for muscle, research shows that intensity, frequency, and timing matter more than simply “doing cardio.”
Key takeaway from the evidence:
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When programmed poorly, cardio can blunt strength and muscle gains
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BUT when managed well, it doesn't interfere, and may even support recovery and performance
Let’s look at where things go wrong (and how to get it right).
Where Cardio Can Hurt Muscle Growth
1. If You’re in a Calorie Surplus, But Burn It Away
To build muscle, you need fuel, usually a calorie surplus.
If you're doing a lot of cardio (especially running, HIIT, long sessions), you might be burning more calories than you think…
➡️ And that pushes you out of a surplus, making it harder to gain size.
2. If Fatigue From Cardio Impacts Your Lifting
Doing a 10k run before or after leg day isn’t just unnecessary, it’s counterproductive.
Heavy resistance training sends a very different signal to your body than long, steady-state cardio.
Mixing both too close together can lead to interference, where your recovery and adaptation to lifting are compromised.
If you’re unsure whether you’re fuelling enough for your training volume, this is a good time to revisit your daily protein target, especially when trying to recover and grow.
Where Cardio Helps (Yes, Really)
Despite the interference risk, cardio isn’t the enemy, it can help if applied smartly:
✅ Improves Recovery
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Better circulation = improved nutrient and oxygen delivery to muscles
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Helps flush waste products and reduce post-training soreness
✅ Supports Heart and Lung Health
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A strong cardiovascular system helps you recover faster between sets, sessions, and even between reps
✅ Helps You Train More, Not Less
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If you’re gasping halfway through a strength session, you’re not maximising your performance
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Good baseline fitness means you can get more quality out of each workout
Real-World Application: How We Use Cardio Without Blunting Muscle Growth
💡 Modality matters:
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Stationary bikes, sled pushes, incline walking = low-impact and easier to recover from
💡 Timing matters:
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Keep cardio sessions separate from strength days where possible, or place them far enough apart (6+ hours)
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Prioritise lifting if muscle growth is your primary goal
💡 Duration & intensity matter:
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Short, purposeful sessions (10-30 minutes) are usually enough
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Long, high-volume cardio can increase interference, especially if done frequently
As always: keep the main goal the main goal.
Many of our clients over 40 benefit from strategic cardio for health without compromising strength. Here’s what to consider as you age.
Final Thoughts
Cardio can negatively impact muscle gain, but only if it’s unmanaged, overdone, or poorly timed.
If you're looking to build muscle and want to stay fit and healthy at the same time:
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Keep cardio intentional and low-impact
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Avoid intense conditioning sessions around heavy training days
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Make sure you’re still in a slight calorie surplus
Need help blending strength and cardio in your current training plan?
Click here to join and we can guide you
References:
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Wilson, J. M., et al. (2012). Concurrent training: a meta-analysis examining interference of aerobic and resistance exercise. Journal of Strength and Conditioning Research.
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Schoenfeld, B. J., et al. (2021). The effect of aerobic training on muscle hypertrophy: A systematic review and meta-analysis. Sports Medicine.
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