If you've ever stepped into a gym or scrolled through fitness content online, you've likely encountered the persistent belief that cardiovascular exercise is the ultimate weapon for weight loss. This myth has dominated fitness culture for decades, leading countless people to spend hours on cardio machines in pursuit of their weight loss goals. But here's the truth: while cardio has its place in a healthy lifestyle, it's not the magic bullet for weight loss that many believe it to be. That said, it’s still an important component to a well rounded fitness program and we will discuss its place later in this article.
The belief that cardiovascular exercise is superior for weight loss stems from a combination of factors that seem logical on the surface. First, cardio burns calories during the activity itself, and you can often see this calorie burn displayed right on the machine. Second, many people notice initial weight loss when they start a cardio routine, which reinforces the connection but this overlooks other factors like being more physically active in general, and possible changes in diet and other habits. Finally, the fitness industry has long promoted the concept of the "fat burning zone," which we'll explore shortly. While the basis of the fat burning zone may actually have some basis in physiology, the practical implications do not justify trying to do long workouts in that range over other methods and training intensities that may burn more calories total.
Additionally, cardiovascular exercise has been extensively studied and promoted by health organizations for its benefits to heart health. Over time, these cardiovascular benefits became conflated with weight loss benefits, creating a powerful myth that persists today. This isn’t to say that cardiovascular exercise is not useful or important but with all the miscommunication out there (especially on social media), I think it’s important for us to understand ‘why’ we do things.
One of the most significant flaws in the cardio-for-weight-loss argument is the misunderstood concept of the "fat burning zone." This zone refers to a heart rate range (typically 60-70% of your maximum heart rate) where your body supposedly burns the highest percentage of calories from fat rather than carbohydrates.
The fat burning zone concept is based on something called the respiratory exchange ratio (RER), which measures the ratio of carbon dioxide produced to oxygen consumed during breathing. When this ratio is lower, it indicates that your body is using more fat for fuel. When it's higher, you're using more carbohydrates.
Here's the flaw when trying to apply this practically: while you may burn a higher percentage of fat calories in this zone, you're burning fewer total calories overall. The total calorie expenditure matters far more for weight loss than the source of those calories during exercise. As you can see, it is technically true that we are using more fat in an intensity associated with lower RER, but the calories expended at lower intensities of exercise are lower overall than in a more intense training session.
Before you abandon cardiovascular exercise entirely, it's important to understand its genuine benefits. Cardio exercises strengthen your heart muscle, improve circulation, and enhance your body's ability to deliver oxygen to working muscles—a measure of aerobic capacity.
Regular cardiovascular exercise can lower blood pressure, reduce the risk of heart disease, improve mental health, and boost overall energy levels. It also enhances your recovery ability, meaning you'll bounce back faster from other types of exercise and daily activities due to building greater total work capacity. For beginners, cardio provides an accessible entry point into fitness that can build confidence and establish healthy habits. Studies also show a high correlation to reduction of all-cause mortality (death from any cause) and high cardiovascular fitness (measured in studies as VO2max). We discuss this more in our health and wellness course and we will also likely explore this topic specifically more in upcoming posts.
These benefits associated with cardiovascular fitness are significant and shouldn't be overlooked. The key is understanding that while cardio contributes to overall health and can support weight loss efforts, it's not the most efficient tool for weight loss on its own.
When it comes to weight loss, the fundamental principle is simple: you need to create a caloric deficit, meaning you burn more calories than you consume. This deficit can be achieved through diet, exercise, or preferably both; and more heavily weighted toward diet. The mode of exercise whether it's running, lifting weights, or dancing, matters less than the total number of calories expended.
This is where many people get tripped up. They focus intensely on the type of exercise rather than the bigger picture of energy balance and the independent health benefits of performing both cardiovascular and resistance training on a regular basis. A 30-minute strength training session might burn fewer calories during the activity than a 30-minute jog, but if the strength training session leads to better long-term muscle preservation and metabolic health, it may be more beneficial for sustained weight loss. In other words, we need both modalities: resistance training and cardiovascular training, but we need to think of the long game too while considering the short term process goals of expending more calories.
For those concerned about time efficiency, High-Intensity Interval Training (HIIT) offers a compelling alternative to traditional steady-state cardio (like using a machine or going for a long slow jog). HIIT involves alternating periods of intense effort with periods of rest or low-intensity recovery. Many people find this more engaging than steady state cardio and you still get the majority of the cardiovascular benefits.
For example, you might sprint for 30 seconds, then walk/jog for 90 seconds, repeating this cycle for 15-20 minutes. This approach typically burns more calories per minute than steady-state cardio and can provide similar cardiovascular benefits in less time as mentioned previously.
HIIT's efficiency comes from the high intensity of work periods, which demands more energy and can lead to greater total calorie expenditure even in shorter sessions. For busy individuals, this time efficiency makes HIIT an attractive option for supporting weight loss goals. Our health and wellness course gets more into how to construct these intervals and fit them into your exercise routine while balancing it out with your other exercise habits like resistance training.
While we're debunking cardio myths, it's worth highlighting why resistance training (lifting weights, bodyweight exercises, or using resistance bands) might be superior for long-term weight loss success. Resistance training builds and preserves muscle mass, which is metabolically active tissue.
More importantly, resistance training improves insulin sensitivity—your body's ability to effectively use carbohydrates for energy rather than storing them as fat. This metabolic benefit can have lasting effects on weight management, even when you're not exercising and it also has huge implications for preventing type 2 diabetes.
Muscle tissue also provides a higher resting metabolic rate (RMR)—the number of calories your body burns at rest through normal biological functions. However, it's important to have realistic expectations about this benefit.
Here's where we need to pump the brakes on some other common and related fitness myths. While muscle mass does increase your resting metabolic rate, the effect is often overstated. Each pound of muscle burns approximately 6-7 calories per day at rest. This is helpful, but not enough to dramatically change your daily calorie needs as it may sound like it from certain sources on the internet.
Similarly, Exercise Post-Exercise Oxygen Consumption (EPOC), the elevated calorie burn that continues after intense exercise, is often oversold as well. EPOC refers to the additional oxygen your body needs to return to its pre-exercise state, which requires energy and burns additional calories. While HIIT and resistance training can create more EPOC than steady-state cardio, we're typically talking about an extra 50-100 calories, not the hundreds that some fitness influencers and training programs might suggest.
The bottom line is that there are no significant "free" calories from exercise. Consistent effort in both exercise and diet remains the most reliable path to weight loss. That said, every little bit helps but we need to have realistic expectations so we aren’t disappointed or get duped by clever advertising.
Understanding these truths doesn't mean you should avoid cardiovascular exercise. It means you should approach it with the right expectations. Cardio is excellent for heart health, mental well-being, and overall fitness. However, for weight loss, focus on creating a sustainable caloric deficit through a combination of dietary changes and various forms of exercise. As I mentioned earlier, the largest calorie deficit should absolutely be coming from your diet. We can explore that more in a future article.
Consider incorporating HIIT for time efficiency, resistance training for long-term metabolic health, and yes, keep some steady-state cardio for its specific cardiovascular benefits. Most importantly, choose activities you enjoy and can stick with long-term, because consistency trumps trying to be perfect or ‘optimal’ every time.
The most effective weight loss approach isn't about finding the "perfect" exercise—it's about creating sustainable habits that you can maintain for life. Start where you are, use what you have, and do what you can. It all adds up and you can build on the foundation that you lay out for yourself.
