What’s The Best Cardio For Bodybuilders?

Improve Your Health While Keeping Your Gains

Hearing some bodybuilders talk about cardio, you’d think simply elevating your heart rate could melt muscle away. In reality, the truth is much more nuanced than that. Cardio can either support your muscle gains or sabotage them.

It all depends on whether you’re using the right cardio in the right way so you keep your gains while increasing your health. In this article, we’re going to tell you what the best cardio is for bodybuilders and how to apply it. 

Mechanisms: How Cardio Can Influence Hypertrophy

The reason people are concerned with performing cardio alongside hypertrophy training is the belief that it will blunt their progress or even decrease the amount of current muscle. 

In reality, there is some truth to these claims as cardio training can interfere with muscle growth through several mechanisms.

• Cortisol and Catabolism – Excessive or poorly timed cardio, especially long-duration, can elevate cortisol, which promotes muscle protein breakdown.
• Interference Effect – Endurance training may activate AMPK signaling, which can blunt mTOR—the key pathway for hypertrophy—if volume and recovery aren’t managed (Fyfe et al., 2014).
• Blunted Anabolic Processes – Excess endurance can reduce the hormonal and cellular signals (like testosterone and mTOR activity) that drive muscle growth.
• Reduced Strength and Power Adaptations – Excessive cardio, especially running, causes muscle damage and fatigue that can limit strength development when improperly scheduled (Sporer & Wenger, 2003).

However, these mechanisms don’t automatically mean that going for a run eats your biceps, and it doesn’t mean cardio will destroy your gains. It just means you need to train smart. Like always.

Will Cardio Kill My Gains?!

Asking “Will cardio kill my gains?” is a bit like asking: Will cardio help me lose weight? Or, will lifting weights help me build muscle?

You might be inclined to answer one way or the other, but the truth is, it’s dependent on an array of variables along with its application. The confusion often comes from the many different ways one can perform cardio.

When done correctly, cardio can support your health, recovery, and even your lifting performance.

When done recklessly, it can eat into recovery, burn through muscle, and blunt hypertrophy.

Due to these variables, research examining the interference effect between strength/hypertrophy and endurance training has found mixed results (Fyfe et. al, 2014). You need to consider;

• Different modes of cardio: cycling, running, swimming, rowing
• Different methods of training: steady-state (Zone 2), intervals, HIIT, long sessions vs. short sessions
• How you balance different variables: nutrition, recovery, training volume

So yes, cardio can hurt muscle growth if your training is mismanaged with too much volume and insufficient nutrition. 

However, that research has also found no negative effects when managed appropriately. In fact, one study found endurance training can actually increase hypertrophy!

The key is smart integration, and integrating cardio doesn’t just kill your gains, it can actually help support muscle growth and overall muscle growth.

How Cardio Can Support Muscle Growth

When done strategically, cardio actually enhances bodybuilding in several ways:

1. Helps control calories – Burning extra energy makes it easier to stay lean in a bulk or create a deficit during a cut (Willis et. a; 2012) (Tan et. al, 2023).
2. Strengthens your cardiovascular system – Better heart health improves recovery between sets and keeps you training longer.
3. Builds work capacity – Cardio increases endurance so you can handle more training volume without gassing out (Willis et. al, 20212)

Cardio doesn’t just “burn calories”, it improves your entire engine. That translates to more reps, heavier sets, and ultimately, more muscle.

More importantly, while many lifters ask “What if I do cardio?” bodybuilders rarely ask “What happens if I don’t?”

Completely ignoring cardio can actually cause problems that eventually hold back your lifting, your physique, and even your health.

1. Decreased Work Capacity- Without cardio, you’ll gas out faster during high-volume training. That means longer rest periods, fewer quality sets, and less overall volume, the exact opposite of what builds muscle. Research has shown that combined aerobic and resistance training helps with maintaining or increasing performance under fatigue. (Willis et al., 2012) 

2. Higher Risk of Health Issues- Bodybuilding without cardiovascular training often means bigger muscles but a weaker heart. Skipping cardio increases the risks of high blood pressure, poor circulation, and metabolic issues. You might look strong, but your underlying health could be fragile.

3. Slower Recovery- A stronger cardiovascular system clears waste products and delivers nutrients to muscles more efficiently. Without cardio, recovery between sets (and between workouts) takes longer, limiting how often you can train hard. This is largely due to a lower capability of producing ATP (Tomlin & Wenger, 2001)

Best Types of Cardio for Bodybuilders

Not all cardio modes are created equal when it comes to bodybuilding. Some interfere with strength and hypertrophy more than others. Here are the most effective choices:

(You’ll realize we don’t have running listed here, go check that out here!)

1. Cycling (Best for Longer Sessions)

Cycling is likely the best choice of endurance exercise for bodybuilders looking to add moderate-intensity cardio.

• Low impact on the joints compared to running
• Builds lower-body endurance without excessive muscle damage
• Potential hypertrophy stimulus during hill climbs or sprints
• Less interference effect on strength training versus running, according to research (Murach and Bagley, 2016)

It’s also easier for most lifters to sustain a 45–60 minute ride than it is to jog for the same duration.

2. Rowing (Full-Body Conditioning)

Rowing machines offer one of the few cardio options that meaningfully engage the upper body.

• Full-body activation: legs, back, shoulders, and arms
• Excellent for short, intense intervals
• Very challenging for beginners to sustain longer than 10–15 minutes

Because rowing is so demanding, it’s better suited for interval work or conditioning “finishers” rather than steady long sessions.

3. Stairclimber (Leg Development and Conditioning)

The stairclimber is brutal but effective.

• Targets glutes, quads, hamstrings, and calves
• Improves anaerobic endurance
• Difficult to sustain for long durations, but excellent for 15–25 minute sessions

It doubles as a light hypertrophy tool for legs while still delivering cardiovascular benefits.

4. Swimming (Best for Active Recovery)

Swimming offers a unique blend of cardio and recovery benefits:

• Very low impact and easy on joints and connective tissue
• Engages the whole body in a non-load-bearing environment
• Excellent for recovery between lifting days

For bodybuilders, swimming works best as a supplement rather than the main form of cardio.

5. Rucking / Incline Treadmill (Low-Impact Workhorse)

Rucking, walking with a weighted backpack, originates from military training. It’s highly effective for long, steady cardio.

• Sessions last 45–90 minutes at a manageable pace
• Inclines or hills mimic real-world resistance and strengthen lower-body endurance
• Bone-loading stimulus adds durability

If outdoor trails aren’t available, the incline treadmill is a great substitute. Just be cautious of long rucks on pavement, which can be stressful on joints over time.

How to Add Cardio Without Losing Muscle

Cardio doesn’t need to be complicated—but it does need structure. Follow these guidelines to keep your gains intact:

1. Keep cardio moderate – 2–4 sessions of 20–45 minutes per week is plenty for most bodybuilders (Panissa, et. al, 2022), (Wilson et al. 2012), 
2. Fuel properly – Eat enough calories and hit protein targets (1.6–2.2 g/kg body weight).
3. Separate sessions when possible – Do cardio and lifting on different days, or at least 6+ hours apart. If you must combine, lift first and do cardio second. If you must do cardio first, try to separate by at least 8 hours (Sporer et. al, 2003)
4. Prioritize recovery – Sleep, hydration, and stress management are as important as your training split.
5. Adjust for goals – In a bulk, keep cardio minimal and low-impact. In a cut, gradually increase cardio to support fat loss without slashing food too aggressively.

Cardio and Bodybuilding FAQ

1. Should you do cardio before or after lifting?

Always lift first if they’re in the same session. Lifting requires peak energy and coordination, while cardio can be done in a slightly fatigued state without major issues.

2. How much cardio is too much?

If it starts interfering with recovery, strength progression, or appetite, scale back. For most lifters, anything beyond 4–5 hours of cardio per week risks diminishing returns.

3. Does HIIT build muscle?

HIIT can improve conditioning and burn calories, but it’s not a substitute for progressive overload in weight training. Think of it as supplemental, not primary.

4. Is fasted cardio bad for muscle?

Not inherently, but it increases the risk of muscle breakdown if you train intensely and delay refueling. If you prefer fasted cardio, keep it low-intensity and eat protein afterward. Keep in mind that muscle loss is at greater risk when you first begin.

5. What’s the best cardio for cutting vs. bulking?

• Cutting: Moderate cycling, incline walking, or rucking are great for consistent calorie burn.
• Bulking: Short, low-impact cardio sessions (cycling, swimming) to maintain heart health without impairing recovery.

Final Word: Cardio Is a Tool, Not a Threat

For bodybuilders, cardio isn’t the enemy and can actually improve your gains. And remember, not doing cardio also brings about its own problems. The key is balance: select modes that minimize interference, keep sessions moderate, support your lifting goals, and remember to eat!

References 

1. Fyfe, J. J., Bishop, D. J., & Stepto, N. K. (2014). Interference between concurrent resistance and endurance exercise: Molecular bases and the role of individual training variables. Sports Medicine, 44(6), 743–762. https://doi.org/10.1007/s40279-014-0162-1
2. Fyfe, J. J., Bartlett, J. D., Hanson, E. D., Stepto, N. K., & Bishop, D. J. (2016). Endurance training intensity does not mediate interference to maximal lower-body strength gain during short-term concurrent training. Frontiers in Physiology, 7, 487. https://doi.org/10.3389/fphys.2016.00487
3. Murach, K. A., & Bagley, J. R. (2016). Skeletal muscle hypertrophy with concurrent exercise training: Contrary evidence for an interference effect. Sports Medicine, 46(8), 1029–1039. https://doi.org/10.1007/s40279-016-0496-y
4. Panissa, V. L. G., Greco, C. C., Ribeiro, N., Julio, U. F., Tricoli, V., & Franchini, E. (2022). Concurrent training and the acute interference effect on strength: Reviewing the relevant variables. Strength & Conditioning Journal, 44(3), 46–57. https://doi.org/10.1519/SSC.0000000000000668
5. Sporer, B. C., & Wenger, H. A. (2003). Effects of aerobic exercise on strength performance following various periods of recovery. Journal of Strength and Conditioning Research, 17(4), 638–644. https://doi.org/10.1519/00124278-200311000-00005 
6. Tan, J., Krasilshchikov, O., Kuan, G., Hashim, H. A., Aldhahi, M. I., Al-Mhanna, S. B., & Badicu, G. (2023). The Effects of Combining Aerobic and Heavy Resistance Training on Body Composition, Muscle Hypertrophy, and Exercise Satisfaction in Physically Active Adults. Healthcare (Basel, Switzerland), 11(17), 2443. https://doi.org/10.3390/healthcare11172443 
7. Tomlin, D. L., & Wenger, H. A. (2001). The relationship between aerobic fitness and recovery from high intensity intermittent exercise. Sports Medicine, 31(1), 1–11. https://doi.org/10.2165/00007256-200131010-00001 
8. Willis, L. H., Slentz, C. A., Bateman, L. A., Shields, A. T., Piner, L. W., Bales, C. W., Houmard, J. A., & Kraus, W. E. (2012). Effects of aerobic and/or resistance training on body mass and fat mass in overweight or obese adults. Journal of Applied Physiology, 113(12), 1831–1837. https://doi.org/10.1152/japplphysiol.01370.2011