How Many Calories Does Weight Lifting Burn?

How many calories does weight lifting burn? While recent technology has given us tools to estimate calories burned with resistance training, there are several factors that affect this figure. Here’s what you should know, according to a personal trainer and dietitian. 

Despite what your smart watch or exercise machines at the gym may make you think, it’s very difficult to definitively tell you how many calories are burned lifting or doing any form of exercise. Though there are many cardio and weight lifting calculators out there that claim to know your calories burned, they are rarely accurate. 

In fact, one study showed that even brands of fitness trackers that claim to be the most accurate were found to be off on their estimates of calorie burn by an average of 27%, with the most inaccurate readings being off by 93%.

This is why dietitians discourage active individuals from adjusting their diet based on this kind of data alone. There are a number of factors that influence the amount of calories burned during exercise. Let’s look at some of those factors more closely for an accurate estimate of how much energy you’re burning from weight lifting.

Does Lifting Weights Burn Calories?

Lifting weights absolutely burns calories, just like other forms of exercise. It’s a misconception that cardio is the only way to burn calories and the best way to lose fat, but this is not the case. 

If you aren’t dripping with sweat after a weight session the same way you would be after an intense cardio session, this doesn’t mean you didn’t burn plenty of calories. But how many did you burn? For example, how many calories does 30 minutes of weight lifting burn?

How is Calorie Burn for Weight Lifting Calculated in Studies?

The data seen on exercise machines, body weight exercises, or in apps that track physical activity are typically calculated by indirect calorimetry in studies. This allows researchers to assess the calorie burn in scientific research. This is called a MET (Metabolic Equivalent of Task) value.

The problem is, MET values are calculated by measuring how much oxygen is consumed during specific exercises. Given the fact that the amount of oxygen consumed varies widely depending on your body composition, level of effort, and level of exercise intensity along with other factors, there isn’t a simple answer to how much you burn. Thus, more research is needed to reliably quantify certain movements. 

How Do Age and Gender Come into Play?

Studies have suggested that women lose less fat than men overall even when in the same calorie deficit from diet and exercise. Scientists believe it is because women hold onto more fat for the biological purpose of maintaining hormonal balance, considering fat tissue plays a role in estrogen production in women. Finally, women have less ability to gain muscle compared to men. 

It has also been shown that people who are older in age burn fewer calories than younger individuals. Also, muscle mass and the ability to gain muscle decreases by 3-8% each decade after the age of 30. This leads to a decrease in basal metabolic rate, which we’ll discuss more later, but it can impact how many calories are burned during weight training given there are fewer muscle fibers available to contract. 

Heavy Weights Vs. Light Weights for Calorie Burn

The calories burned during weight lifting can also be influenced by the heaviness of the weights you are lifting. This is referred to by fitness professionals as “the volume.” If you’ve ever heard about more reps or more weight for fat loss, this is mostly accurate. 

One study done in men who lifted heavy weights vs light weights found that the men who lifted heavier weights burned more calories. This is likely due to the fact that more muscle fibers need to be recruited when lifting higher volume versus lighter weights that don’t require as much effort. 

Does Lifting Weights Give You a Faster Metabolism?

Here are two main factors to consider with metabolism and weight lifting.

1. Body Composition and Basal Metabolic Rate (BMR) 

Before we talk about weightlifting’s impact on metabolism, let’s talk about your BMR or basal metabolic rate. Your basal metabolic rate is the term given to the number of calories your body burns at rest, or when you are doing no physical activity. Energy is also consumed by involuntary body processes such as breathing, heartbeating, and digestion. 

Muscle Mass and BMR

However, your body composition also influences your BMR. The more muscle you have, the higher your BMR tends to be. That’s because your muscles are almost always working. Even if you are sitting down, your core muscles are working just to keep your body upright and the more muscle you have, the more energy is burned to make them work. 

Fat Mass and BMR

Conversely, it has been shown that those with more fat mass have a lower BMR than those with more muscle mass due to a less efficient metabolism. Therefore, for people with excess fat tissue, it is recommended to do resistance training in order to gain more muscle mass.

2. Excess Post-Exercise Oxygen Consumption - EPOC

Weightlifting has probably the biggest edge over cardio in terms of calorie burn and weight loss because it has a larger impact on EPOC, or Excess Post-Exercise Oxygen Consumption. EPOC describes the calories you burn after exercise is complete. How is this possible?

Well, when you exercise, your body builds up something called oxygen debt. To perform exercise, the body needs more oxygen than usual. So, when you find yourself breathing harder during exercise, it’s because your body is trying to get more oxygen to your muscles. 

The body also burns energy by restoring your body back to its pre-exercise state as well as repairing your muscles from the microtears that occur during weight lifting. This effect is much higher in weightlifting compared to cardio, according to science. One study even found that subjects had a higher RMR for up to 38 hours after weight lifting, with no such increase being seen after cardio training. 

Can I Lose Weight By Lifting Weights Only?

From the sound of it so far, one would assume that all you need to do is lift weights everyday and drop weight like crazy, right? Well, not exactly. While lifting weights does burn calories both during and even after exercise, studies have shown that a combination of both cardio and weight lifting produces more weight loss than lifting weights alone. The same study also showed that benefits to heart health are better when incorporating both modes of exercise in your regimen rather than just one. 

Also, diet cannot be ignored. You can lift as many weights as you want, but also controlling your intake and having a balanced, nutritious diet to support both your health and your exercise performance is paramount to maintaining optimal weight and optimal health. 

So, How Many Calories Does Weight Lifting Burn?

As summarized above, the exact number of calories burned weight lifting is difficult to put a number on. Calorie burn is influenced by a number of factors that varies from person to person. 

However, it’s safe to say that anyone trying to lose weight could benefit from doing some resistance training, and the exact number shouldn’t be the focus. Lifting heavy weights has been shown to raise one’s BMR, allow one to burn more calories after exercise and help to improve overall health. 

Although calories burned from weight loss help manage weight, diet has the most impact on how much weight you lose. If you’re looking to build muscle rather than losing weight by starting a weight training program, it may be a good idea to lose some fat before you begin. Since I am a personal trainer and dietitian, I can work with you to create a personalized weight training and nutrition plan to help you meet your weight and wellness goals. If you’re interested in getting started, contact me today.