There was a time when doing hours upon hours of cardio was considered the best way to get lean. Though times have changed, many women still choose treadmill intervals and spin classes over pumping iron — despite the growing popularity of weightlifting. That may be because some still believe that lifting weights will make them "bulky.”
This myth is so pervasive that celebrity trainer Ben Bruno decided to post a video on his Instagram showcasing some of his strongest female clients. Among them: Jessica Biel, Kate Upton, and Rita Ora.
It’s not just Bruno’s A-List clients who have discovered the benefits of lifting weights. After giving birth to her second child, Hillary Duff shared that she traded cardio for bodybuilding-style strength workouts. She added that she’s never felt so strong or lean before.
But is it really a good idea health-wise to stop doing cardio completely? And can strength training alone help with weight-loss (if that’s your goal)? Ahead, expert trainers put things in perspective.
Yep, strength training is one of the best things you can do for your physique.
There are several pretty big advantages to focusing on weightlifting when you’re trying to get in better shape.
If you’re hoping to change the way your body looks, lifting weights for strength and muscle growth is a great idea, says Dominic Matteo, a certified personal trainer and MasterClass Instructor at Precision Nutrition. "It helps create desirable optical illusions,” he explains. "For example, more defined or broader shoulders or larger glues can both make your waist look smaller.”
Plus, there’s a difference between losing weight, which may be a combination of muscle and fat, versus losing just fat. Strength training can help you lose fat while preserving muscle, whereas a cardio-only regime is more likely to result in losing both fat and muscle. "If you lose weight without strength training, this typically leaves you looking like a smaller version of where you started,” Matteo points out. In other words, you wouldn't have any of the muscle tone or definition people are usually looking for when they say they want to lose weight.
And there’s another good reason to prioritize fat loss over weight loss: "The more lean muscle mass you have, the more energy your body expends at rest,” explains Stephen Foster, CSCS, trainer at TRAINIAC. So when you have more muscle mass, you burn more calories — even when you’re not exercising. (Although it’s important to note that having more muscle doesn’t magically mean you can constantly overeat and still maintain your weight or lose fat.)
As for why people cite feeling better than ever when they focus on strength training, there are many reasons this could be happening, according to Kourtney Thomas, CSCS*D, a certified personal trainer. "Strength training can be one of the single most empowering things a person can do for their body, mind, and soul,” she says. Plus, strength training is known to improve symptoms of depression and anxiety, energy levels, and body image. "When those things go up, we absolutely feel better,” Thomas points out.
But to change your body, strength training alone probably won’t cut it.
While lifting weights can definitely help you lose fat, there are many other factors at play, Matteo emphasizes. And he’s not just talking about cardio. "Nutritional intake, overall movement, sleep, and stress are all part of this puzzle,” he says. "Ignore any one of those when trying to lose fat, and it becomes more difficult.” That’s because all of these factors can impact your energy balance, or calories in vs. calories out, which ultimately determines whether you gain or lose weight.
Plus, most people need some cardio to stay healthy.
It’s important to understand that "trading cardio for weights” doesn’t mean you should sit on the couch all day except for when you hit the gym.
The American Heart Association recommends 150 minutes of moderate aerobic activity or 75 minutes of vigorous aerobic activity per week. (Ideally, it’s spread out over the course of the week.) Thing is, most people see these guidelines and think, "Okay, I have to spend 150 (or 75) minutes in the gym doing cardio.” But that’s not really the case.
For most people, a baseline of 10,000 to 13,000 steps a day is a solid starting point, Matteo says, particularly if you can accomplish that with some brisk walking — like when you’re rushing to catch the subway or to get to your car faster in the freezing parking lot. Other moderate aerobic activities that fit the bill include swimming, mowing the lawn, and gardening.
When it comes to those 75 minutes of vigorous aerobic exercise — which includes things like running, dance cardio, and spin classes — you don’t actually have to do these for better health if you’re already getting enough moderate activity.
"Unless part of your goal is rapid improvement of cardiovascular health, slowly adding cardio [in the gym] only as needed for fat loss is the way to go,” Matteo says. Of course, not everyone is looking for fat loss. If your main goal is to be more aerobically fit— maybe you want to run a half-marathon, have a hiking trip coming up, or your main goal is to feel less winded going up the stairs — then more vigorous cardiovascular exercise would obviously play a more important role in your workout plan.
What’s more, weightlifting may count as cardio in some cases, depending on how high your heart rate gets. "In order to 'double up,' your heart rate needs to remain up,” explains Lena Marti, a certified personal trainer. The exact heart rate threshold will depend on your age and level of fitness, but usually, you want to be between 50 and 60 percent of your maximum heart rate for moderate aerobic activity and 60 to 85 percent of your maximum heart rate for vigorous activity. "Ways to keep your heart rate up while strength training are to cut down on rest time between sets, or add a full-body, aerobic exercise to a circuit like burpees or kettlebell swings. These exercises challenge the body both in strength as well as cardio.”
But too much cardio can keep you from reaching your goals.
Overdoing it with cardio can negatively impact fat loss for two main reasons, Marti says. "The first is that it could be messing with your hormones; specifically, your cortisol levels,” she explains. While all exercise increases cortisol (or your "stress hormone” levels to a degree, too many long bouts of cardio, together with the high-stress environment most people live in these days, can cause your cortisol to stay elevated for longer periods of time.
"Having high cortisol levels can actually cause you to plateau, or potentially even make you gain weight,” Marti adds. "Secondly, cortisol is catabolic in nature. Catabolic reactions work to break down muscle. If we are working to lose weight, we do not want our bodies in a catabolic state. We want our bodies to be in an anabolic state; the state in which our bodies are building lean muscle mass.”
Foster agrees, noting that this is one of the reasons he recommends doing cardio after lifting weights if you’re doing both on the same day. "To get the most out of your workout, it’s best to avoid fatiguing your muscles with cardio before touching the weights,” he explains.
What’s more, doing more cardio has the potential to make you feel very hungry, Matteo points out. Considering that nutrition is a key part of any fat loss plan, this could be problematic. Matteo also prefers to use what people traditionally think of as "cardio” as a tool later on in a person’s fat loss journey. Most people eventually plateau, and adding in more cardio at that point can help increase their "calories out.” But if you start doing a ton of cardio right from the start, your only option when this happens would be to eat less.
If you like doing cardio, there’s no reason to stop doing it.
... But on the flip side, if you’re not into spending dedicated time on cardio in the gym, it’s probably not such a big deal. The key is just to make sure that the cardio you’re doing matches up with what you hope to achieve.
Consider your goals.
There are times when focusing on cardiovascular training makes sense. "If your goal is performance-based for running a marathon or triathlon, then cardio for hours on end can be beneficial,” Foster points out. But if you enjoy doing cardio and your goal is fat loss, mix in some strength training. "A good mix would be adding resistance training into your routine three times a week and focusing on cardio twice a week. Or even ending your resistance training workouts with 15-20 minutes of cardio,” Foster says.
Remember that "cardio” can have many different meanings.
"There are many kinds of cardio and a lot of different ways you can challenge yourself that aren’t just running outside for an hour,” Marti points out. Walking, weightlifting, shorter HIIT workouts, and just generally being active in your day-to-day life can count towards your cardiovascular activity.
Know that what works for every person is different.
"HIIT might work really well for one person, but doesn’t aid in weight loss for another,” Marti notes. Ultimately, how much cardio you should do — and what type — depends on you: your goals, your lifestyle, what type of exercise you enjoy, how stressed you are, your sleep schedule, and more.
The bottom line? If you’re spending a lot of time and effort on cardio in the name of weight loss and you don’t enjoy it, cutting back isn’t necessarily a recipe for disaster, provided that you’re getting enough activity in your day-to-day life outside the gym. But if you love your long runs, elliptical sessions, or spin classes? Keep on doing you.