How are calories burned during exercise?

We all know that when it comes to weight loss and energy balance, it’s a matter of calories in versus calories out. But when you exercise, do you really know how many calories you’re burning?

It’s important to learn how many calories you typically burn so you can control your weight, prevent obesity and lower your cancer risk.

We talked to Karen Basen-Engquist, Ph.D., Director of the Center for Energy Balance in Cancer Prevention and Survivorship, to get more information on how to determine calories burned. Here’s what she had to say.

How do you know how many calories you’ve burned during a workout?

Measuring the exact number of calories you burn can be difficult. There are a few ways to measure your calorie burn. You can:

• Use an activity tracker or an app that will estimate your calorie burn for you. But be careful with these. The accuracy can vary from product to product.
• A heart rate monitor is one of the best ways to measure your calorie burn. Your heart rate indicates how much effort it takes for you to do a certain activity, and that effort determines the calories you burn. If a heart rate monitor indicates your calorie burn, it’s more likely to be accurate than the average activity tracker because it’s taken your specific heart rate in to account.
• A MET values chart can also show you how many calories are typically burned during specific activity based on your weight. This chart was created by researchers and used widely throughout the medical community. A sample of this chart is featured below.

Which helps you lose more weight: diet or exercise?

Diet. Cutting calories and eating healthy will help you lose weight. Exercise alone probably won’t help you lose weight, but it will help you keep the weight off.

To lose one pound a week you should aim for a calorie deficit of 500 calories per day, through a combination of reducing the calories you eat and increasing the calories you burn through physical activity. This adds up to 3,500 calories per week, the number of calories in about one pound of fat.

What factors contribute to how many calories are burned?  

Several factors contribute to how quickly an individual burns calories, including:

• The intensity of an activity being performed. The more intense an activity is the more calories an individual burns.
• Weight. People who weigh more burn more calories.
• Body composition. Muscle requires more energy than fat to maintain. People with more muscle burn more calories.  

How much activity do I need to do?

To lower your cancer risk, aim for at least 150 minutes of moderate physical activity or 75 minutes of vigorous activity each week. Remember, you don’t have to do it all at once. You can break it up throughout the day, too. 

As a personal trainer and weight-loss coach, I am constantly answering health and fitness questions from my clients, on social media and in our Start TODAY Facebook group. In this column, I address some of the most common questions and roadblocks that trip people up on their journey to establish a health and fitness routine. 

Should I worry about how many calories I burn during my workout?

With the popularity of fitness trackers and at-home fitness equipment (like treadmills and stationary bikes), the number of calories you burn during each workout is front and center. But how important is this metric and is it something you should really be paying attention to?

People often ask me if it matters how many calories they burn during a workout. I tell my clients that while calories are interesting to note, they are not the sole indicator of how effective a workout is. I prefer that people focus on how they feel during a workout: Do you feel winded? Have you broken a sweat? Do you feel like you’re making progress in the long term with endurance or strength? These things are more indicative of how effective your workout is than the caloric burn.

What exercise burns the most calories? 

Gone are the days of the strict “calories in, calories out” methodology. For weight loss, and specifically for women with hormonal issues or weight challenges, that school of thought does not always yield the desired results. That said, according to the American Council on Exercise, here is the number of calories that someone who weighs 150 pounds would burn doing the following exercises:

• 30 minutes walking (moderate pace): 112 calories
• 30 minutes weight training: 102 calories
• 30 minutes running: 238 calories
• 30 minutes yoga: 85 calories
• 30 minutes spinning (moderate pace): 136

Don’t let calories trump how your body feels

The numbers above may lead someone to ditch yoga for a spin class or force themselves to run instead of walk. But how many calories we burn doesn’t reflect what our body needs. Yes, you can hop on your spin bike and burn more calories than a yoga class, but you’ll be foregoing flexibility, toning and mental-health benefits that your body may be craving. The best workout plan is one that makes you feel good — I never recommend sacrificing that just for the sake of burning more calories. I encourage my clients to feel empowered and to tap into what their bodies need. One day that may be a leisurely walk and the next it may be an intense spin class — and both are solid workout choices.

RELATED: Walking to lose weight: Does it work?

Using calories burned as motivation

Just like daily steps, setting a calorie-burn goal can turn your exercise into a game and motivate you to get moving. However, the number of calories you want to burn through exercise will vary based on your diet, body composition and goals (are you trying to lose weight? Improve endurance?). So if you are going to closely monitor your calorie burn and aim to hit a certain number, I do suggest working with a trainer to determine what a healthy calorie burn goal is for you. I also want to warn against becoming hyper-focused on calories — this can spiral into an unhealthy relationship with food and exercise. If tracking calories burned is fun for you, that’s fine. But if it becomes another stressor or you find yourself feeling discouraged when you don’t burn a certain amount, ditch it.

Ask yourself: Am I reaching my fitness goals?

This is the main question I always ask: Do you feel like your workout routine is helping you reach your goals? Calories are only one way to track the effectiveness of a workout. If you are seeing results on the scale, your clothes fit better or your energy levels and sleep have improved, those are other important signs that your workouts are working for you. However, if you are someone who overeats and consumes more calories than your body needs, tracking how many calories you burn can be helpful in getting in becoming more aware of how you fuel and move your body.

Having a general sense of how many calories you are burning when moving your body is great. But remember, it is only one measure of a workouts intensity and effectiveness and shouldn’t be the end-all-be-all when it comes to rating a workout or choosing which type of exercise to do. For a well-rounded workout routine, focusing on how your body feels and the progress you’re making toward your goals over time is a much healthier approach.

More of your questions, answered!

• I hold weight in my midsection. Can I spot reduce belly fat?
• If all I do is walk, is that a good enough workout?

Is it better to lift heavier weights or do more reps?

Stephanie Mansour is a contributing health and fitness writer for TODAY. She is a certified personal trainer, yoga and Pilates instructor and weight-loss coach for women. She hosts “Step It Up with Steph” on PBS. Join her complimentary health and weight-loss challenge and follow her for daily inspiration on Instagram and in her new app.

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