In the past, there was a belief that adding cardio to your fitness routine could prevent muscle growth. But actually, adding a little cardio to your workout doesn’t make you a cardio bunny or ruin your gains — hybrid fitness (AKA combining strength training and cardio) can actually help build muscle and strength.
Here’s a quick look at what the experts say about the relationship between cardio and muscle growth.
The short answer to the question does cardio kill gains is no, not necessarily. But the idea of cardio hurting muscle growth has been around for a long time. A study published in 1980 said researchers found that people who only lifted weights gained more strength than those who also did cardio. However, training methods have changed significantly since then, and newer research tells a different story. These newer studies show that cardio doesn’t have to get in the way of building muscle and might even help.
“There’s a lot of value in training both cardio and strength same day if you have the time, or if you like to do activities that combine both like uphill hiking, cycling or boot camp classes with a high heart rate plus weights,” says Milica McDowell, DPT, certified exercise physiologist and VP of operations at Gait Happens.
How to balance weights and cardio
Finding balance is critical whether you’re working out a lot or just trying to stay active; you don’t want to overwork yourself or risk injury.
Consider what’s realistic for you. Before committing to a routine, consider your fitness level, goals, and mobility limitations. If you’re trying to lose fat, for example, adding cardio can help create the calorie deficit you need. Or, if you’re short on time, try HIIT workouts that combine strength and cardio. And don’t forget to rest — overtraining can be counterproductive.
The Centers for Disease Control and Prevention (CDC) recommends adults get at least 150 minutes of moderate-intensity physical activity per week and two days of muscle-strengthening activities.
“I like people to workout at least three days a week,” says McDowell. “That could be 50 mins cardio and weights on the same day, or you could split that into five days for 30 mins, plus two strength (days).”
What comes first: cardio or weights?
When you do your cardio workout is ultimately up to you. Again, consider your fitness level, goals, and what works best for your schedule and lifestyle. Some experts recommend doing cardio workouts in the morning and lifting weights in the afternoon, but there’s no one-size-fits-all approach.
One 2021 study suggests that just 20 minutes of cycling might “prime” the muscles to grow more during strength training sessions. The study was small (eight men total), and more research is needed, but it shows that cardio doesn’t have to be the enemy of muscle growth.
“I like cardio first to warm up tissues and your neuromuscular system before weight lifting,” says McDowell. “Doing cardio first also reduces the risk of injury and helps you get mentally ready to perform more complex movements like weight lifting.”
Tips for preventing muscle loss
If you’re worried about cardio sabotaging your gains, McDowell recommends eating enough protein and taking regular rest days to allow your muscles to recover.
“Protein is the major nutrition building block that keeps your muscles healthy,” says McDowell. “A daily recommendation is to eat your body weight in kilograms (or roughly half your weight in pounds) of protein as the base level for healthy individuals. If you’re recovering from injury or surgery, you’ll likely need 1.2 times your BE up to 1.5 times your BW in kilograms.”
Some other tips:
- Listen to your body, and adjust your routine as needed to avoid burnout or overtraining
- Add stress-reduction exercises like yoga, meditation, or spending time in nature to your routine
- Try to get two to three strength training sessions and two to three cardio sessions in per week
- Get at least seven hours of quality sleep per night
- Drink plenty of water throughout the day
- Don’t forget the carbs — healthy carb sources like fruits, veggies, and whole grains will give you the energy you need to get through your workouts
- Track your progress and adjust your training as needed
And, remember McDowell’s no. 1 piece of advice: “DDDS — don’t do dumb s***!”
“Ask a trainer or coach how to properly do new movements or how to properly use equipment,” says McDowell. “Making sure you are using equipment correctly with proper mechanics can help you with gains and boost your longevity via keeping you safe from injuries.”
The bottom line? Cardio doesn’t have to kill your gains. If you balance strength training, cardio, rest, and nutrition, you can become the best version of yourself (at least physically).
