Fact: cardio has great benefits: it strengthens the heart and lungs, reduces the risk of heart disease and stroke, lowers blood pressure, improves cholesterol and helps burn calories. Phew! Having said that, skipping, running and the rest isn’t a panacea – which hasn’t stopped all sorts of cardio myths from being perpetuated. Here, we explain the truth to the most common cardio myths – and how to make sense of the workout itself.
Myth 1: Cardio speeds up weight loss
FACT: Hours logged on those fast-paced gym machines are a surefire way to melt off the weight – after all, it’s the foundation of the cardinal rules of weight loss, right: fewer calories in, more calories out?
Well, yes, but… not all weight loss is equal. “You may lose weight faster doing cardio only, but unfortunately it’s the wrong kind of weight,” says personal trainer Greg Justice.
Cardio alone burns away both fat and muscle. FYI: losing muscle is the opposite of what you want since muscle is what burns fat all day long – even at rest. Besides that, it’s the key to longevity, as emerging studies are showing.
For a lasting change, you have to integrate strength workouts into your routine. “Weight training builds lean muscle mass, which elevates your metabolism and burns more fat, even when you’re not exercising,” says Justice. But! If you’re dead set on getting your heart rate up, there are tons of ways to get the burn with the muscle gains. Justice recommends Metabolic Resistance Training, a hybrid method in which weight training is done at a fast pace, with minimal rest. One example of this double whammy: kettlebell training. Or, lean into these HIIT workouts, which blend resistance and weight training with fast-paced cardio:
Cardio & strength workouts
Myth 2: If you can’t do cardio for an hour, it’s not worth it
FACT: Flat-out not true. Repeat after us: all body movement has benefits – even in terms of calorie burn!
What you can change? How efficiently you burn them. “You may be able to do steady-state cardio longer and burn more calories during that time, but the key is what happens after your workout,” says Justice.
“By doing high-intensity interval training [HIIT], you incorporate intense periods of work with short recovery, so your metabolism is elevated and you’ll be burning kilojoules for up to 38 hours after your HIIT workout is completed.”
If you prefer to pray at the altar of the treadmill, take heart. “The American Heart Association says that doing three 20-minute sessions of cardio at a vigorous intensity (like running) is the equivalent of doing five 30-minute sessions at a moderate level (like fast walking),” says exercise scientist Wayne Westcott. Even 10 minutes at a high intensity is beneficial. Plus, a study suggests that short, infrequent bouts of slow running can do your heart good. The lesson? Every minute counts as movement – and that’s beneficial.
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Myth 3: Fasted cardio burns more body fat
FACT: This one comes from the idea that if your body doesn’t have readily available food kilojoules, it’ll dip into the body’s stored supply, shrinking that muffin top.
Research bears out that the opposite is true: A 2011 meta-analysis concluded fat burn is consistent regardless of whether or not you’ve eaten before a workout. In 2014, another study confirmed this data. And other research shows a negative effect of muscle catabolism (muscle loss) from skipping a pre-workout snack or working out on empty. “Your body needs energy to perform and energy comes in the form of food,” says Justice. “I’m not talking about gorging yourself, but having a small snack before doing cardio can actually help you perform at a higher level.”
Myth 4: You must stay in that “fat-burning zone”
FACT: Like a lot of fitness fallacies, this cardio myth is half true. At a lower intensity – the heart rate deemed the “fat-burning zone” – you will indeed burn a greater percentage of your kilojoules from fat. The zone in question is typically between 64% to 76% of your maximum heart rate – but it depends on a number of factors, including your age.
But before you go ahead and skip every treadmill workout, as Westcott explains, it’s total calories burned that matter for weight loss.
The math: If you run at 11km per hour, you burn 25 percent of your kilojoules from fat, while walking at half that speed burns 40 percent from fat, says Westcott, citing past research. So far, walking has an edge.
Bottom line: Working out at a higher intensity equals more kilograms lost. However, if you need to find the right formula for you (excess stress can push you away from fat-burning potential, no matter how hard you work), speak to a pro.
READ MORE: No Need To Run! This Is The Exact Way To Burn Fat With Walking
Myth 5: Running means you’ve completed leg day
FACT: If only that were true. Unless you’re doing full-on sprints uphill or cranking the bike’s resistance to the point where you can barely push the pedals, you aren’t getting much muscle-building benefit from your workout.
So while you feel like your legs and glutes did some work, in order to get the awesome metabolic gains of building up those largest muscles in your body, you have to incorporate strength moves like squats, deadlifts, and lunges. Not only that, but strength workouts will make you a better runner and cyclist. “Back when I coached track at Penn State, our runners dominated the sport,” says Westcott. “We were the only ones at the time having our athletes strength-train. Now, of course, everybody does.”
Myth 6: The more you sweat, the more fat you burn
FACT: While this is a very novel idea that we’ve all tried at once point (black bag under your hoodie, anyone?), it’s not true – especially not when you understand what sweat actually is. It’s good to also understand that some people naturally sweat more or less than other people.
Sweat is water leaving your body. It’s made up of electrolytes and a small amount of waste products – but none of that is fat. Sweat is, instead, a way for your body to regulate its temperature when it’s high.
How the body actually burns fat? Through carbon dioxide that is breathed out of the body through rigorous exercise and by burning stored fat for energy – something that can only happen through a calorie deficit.
If you’re looking to lose fat, look to your diet first and not only at sweating as much as you can.