If You're Having Trouble Building Muscle Definition, Cardio May Be to Blame


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You’ve been sweating, moving, and logging miles daily, only to see the scale creep up. If weight loss is your goal, the lack of results can feel discouraging. What's more, the inconsistency in anecdotal advice is dually troubling. Perhaps a friend suggested adding weights; another says to stick to running. Another well-intentioned friend says the problem is you’re running the same distance and your body has gotten used to it. Exercising can feel extremely complicated. To help dispel the fog, we spoke to fitness experts to learn how you should be exercising based on your desired outcomes. 

First, Switch It Up

If you're experiencing a plateau, adjust anything you’re doing, says Hannah Daugherty, a certified personal trainer serving on the advisory board for Fitter Living. Making changes to anything from workout intensity, to the number of reps and sets you're doing, to the length of your workouts and the number of days a week you’re exercising can help with avoiding injury and boredom—and can take your workout to another level, Daugherty says. 

Skip Cardio-Only Workouts to Build Muscle

According to Joey Thurman, a certified personal trainer and Kuudose founding trainer, cardio is actually doing the opposite for notable definition. “Lifting weights/strength training helps us regulate human growth hormone and testosterone production, which helps add muscle tissue and is muscle protective,” Thurman says. “On the other hand, long forms of cardio will regulate cortisol and tell your body to store more fat as energy—so lifting and long cardio are battling against each other.”

However, that doesn't mean you should completely pass on all cardio as it does still host fast loss benefits, which will help with revealing the muscle definition. Leighanne Stephens, an online fat-loss coach based in London, recommends 30 to 40 percent cardio and 60 to 70 percent strength.


Focus Primarily on Diet for Fat Loss, but Incorporate HIIT

The most important factor for fat loss is eating a healthy diet that's low on added sugar, processed foods, and trans fat, but exercise can also play a role, says Melissa Morris, an ACSM certified exercise physiologist.

Mixing strength and cardio in a workout is a great way to help speed up fat loss, as cardio tends to burn more calories when you’re exercising, while strength training allows you to burn more calories for up to 48 hours after the workout (your body uses the extra energy to repair those muscles), says Stephens. A short intense cardio workout such as HIIT or other interval training methods allow you to get the necessary effort expended in a short time. But it’s also important to give your body at least one or two days of rest to avoid burning yourself out and having negative impacts on your performance in your workouts—and sometimes even a higher risk of injury due to a lack of energy to maintain good technique. 

For General Health Improvement

Do more strength than cardio, but don’t disregard it completely. A short burst of cardio two-three times a week alongside strength training or daily increased physical activity through things like walking and less sitting can also help when time is short, Stephens says. Sleep is also incredibly important, says Joy Puleo, a certified Pilates trainer and Balanced Body education director. Sleep provides your brain an opportunity to heal, process, and support the intellectual and mental work you do all day. It also helps your body to heal and support the physical work you’ve done, Puleo says.

An ideal workout to balance your body, helping with fat loss in addition to strength, would be a five- or six-day training week at low-to-medium intensity with one or two days of active recovery (stretching or mobility work), says James Taylor, a functional movement coach in London. "You can combine your sessions and perform strength training and cardio on the same day; however, you should perform your most important type of exercise first so that you are less fatigued," Taylor says. "For example, if your primary goal was to build muscle, then you would perform your strength training first, followed by your cardio workout."

But Don’t Do Everything on the Same Day

Cardio and strength have their place in a fitness regimen, but you shouldn’t do intense cardio on the same days you’re doing a strength workout, especially if you’re a beginner, says Tami Smith, owner of Fit Healthy Momma, and a certified personal trainer. "You don’t want to overtax your muscles and risk injury, and your body needs time to recover,"she says. The same goes for strength training and working the same muscles on back-to-back days, Smith says. It’s better to mix up your routine by focusing on muscle-specific groups (upper body, lower body, back/chest, core, ect.) on different days of the week. 

No Matter Your Goal, Don’t Overtrain

It’s a phenomenon not often taken into consideration, says Gina Kim, a physical therapist and owner of an orthopedic physical therapy practice in Columbus, Ohio. “When people continuously go hard or go home with excessive exercise time, volume, or intensity without sufficient recovery time or rest days, overtraining syndrome can come into play,” says Kim. These symptoms include: decreased physical performance, general fatigue, malaise, loss of vigor, insomnia, change in appetite, irritability, anxiousness, loss of motivation and lack of mental concentration. The problem? Researchers don’t know the mechanism of OTS, nor do they know how much is too much training per person. If you’re trying to lose weight, you can see the insidious danger of skipping rest days, not getting proper nutrition, and not allowing for adequate recovery. The easiest way possible to prevent this is by simply taking one day off every week, Kim says. 

Article Sources
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  2. Lucertini F, Ponzio E, Palma MD, et al. High cardiorespiratory fitness is negatively associated with daily cortisol output in healthy aging men. PLOS ONE. 2015;10(11):e0141970.

  3. Kreher JB, Schwartz JB. Overtraining syndrome. Sports Health. 2012;4(2):128-138.

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