How Many Calories Are You Really Burning in the Gym?

“Calories.” Who knew one word could carry so much weight?

Whether you’re trying to get lean, maintain your weight or bulk up, you need to know how many calories you’re consuming and burning. Yet, while it’s easy to count calories in our diet, it’s hard to estimate how many we’re actually burning in the gym.

If you want to truly achieve your goals, you need to understand how many calories you’re really burning each session — that way, you know if you’re doing too little or too much. Unfortunately, what your cardio machine says isn’t always accurate.

In fact, many cardio machines inflate the number of calories you burn. Why? Because they usually take into account your weight and your age only, instead of also including additional factors like fitness level and body composition. A study from the University of California, San Francisco found:

In this article, we’ll break down popular exercise methods and how many calories you’ll actually burn. Use these guidelines to get a better estimate of how much work you’re actually doing every 30 minutes.

Before we dive into various exercises, here are some important things to consider:

• Your basal metabolic rate (BMR) is the number of calories your body requires to carry out daily functions — and accounts for 50–70% of the energy your body uses.
• The more muscle mass you have, the more calories you burn even at rest.
• Physical activity produces heat in your body, called “thermic effect.” It’s the second largest contributor to calorie expenditure at 20%.
• There are approximately 3,500 calories in one pound of fat.

READ MORE > IDEAL REP RANGES FOR WEIGHT LOSS AND 4 MORE GOALS 

In March 2017, Harvard Health Publishing released data on dozens of common activities and their calories burned within 30 minutes for people of varying weights. Here are some of the best in no particular order:

• Running on the treadmill
• Stationary biking
• Swimming
• Circuit training
• Vigorous weight lifting

Read on to see how many calories you’ll actually burn from these exercises. (The lower end of each range is for a 125-pound person and the higher end is for a 185-pound person.)

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TREADMILL

Running can burn a lot of calories. Running at an 11:30-mile pace, burns 270–400 calories in 30 minutes. And if you add an incline to your treadmill or jog on a hilly trail, you’ll burn more.

Even better, if you mix your cardio with high-intensity interval training (HIIT), then you’ll burn a lot more. The low-intensity portions of HIIT typically burn 9–13 calories per minute, while the high-intensity portions burn 12–17. (You’ll also burn calories well after you finish with this method due to the “afterburn” effect.)

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STATIONARY BIKE

Moderate stationary biking burns approximately 210–311 calories per 30 minutes. Vigorous riding — like in an intense spin class — burns 315–466 calories.

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SWIMMING

This is an excellent cardiovascular exercise, which burns 300–444 calories per 30-minute session. Bonus: It’s easy on your joints. So if you find other exercises wreak havoc on your knees, shoulders, etc., jump in the pool for a great workout.

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CIRCUIT TRAINING

This is the kind of training that combines resistance exercises with intense cardio by moving through your strength exercises with minimal rest. In 30 minutes, the average person burns between 240–355 calories.

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VIGOROUS WEIGHT LIFTING

If you hit the weights, you probably burn 90–133 calories in each 30-minute floor session. But remember: The more muscle you build, the more energy your body burns at rest. That’s why lifting weights to build lean muscle should be at the top of your to-do list, regardless of your physique goals.