Why You Shouldn’t Exercise To Burn Calories

Fitness tracker showing calories burned

Have you ever gone to the gym, sweated it out on the treadmill, x-trainer, bike or other piece of cardio equipment then checked your fitness tracker to see how many calories you’ve burned? Then usually been disappointed that it wasn’t as many as you’d hoped! I’ve seen people on Facebook post that they’ve just burned 1,000 calories in an hour at the gym. No, no you didn’t! And if that’s why you’re in the gym then you’re not likely to be in there for the right reasons. You shouldn’t exercise to burn calories; fact! But why? 

Tracking Calories Burned

Counting calories from exercise is just incredibly unreliable. Machines in the gym often tell you how many calories ‘you’ve’ burned in a workout; but the machine is set up in a generic manner. Unless you have input your accurate weight and height, it is reading your heartrate throughout the workout and knows your exact body composition there is no way that this reading is anywhere near accurate. If you run on a treadmill at 5mph for 20 minutes the treadmill might tell you that you have burned 200 calories; but it will tell you that if you are a 60kg female or 90kg male; clearly, they both did not burn the exact same number of calories, therefore, these numbers are nothing more than an arbitrary guide. 

Even if you have a smart watch, that is set up to your height and weight, and reading your heartrate during your workout, the numbers still won’t be hugely accurate. Yes, they will be more accurate than those on a generic treadmill reading but your smart watch doesn’t know your body composition, your hydration status, the room temperature, and all of the other variables that dictate how many calories have been burned. 

Exercise is not to burn calories

So now you know that tracking calories burned from exercise isn’t incredibly accurate, but that doesn’t explain why you shouldn’t exercise to burn calories. Basically, there are many great reasons to exercise, but calorie burn is not one of them. Because, simply, you don’t burn as many calories exercising as you think. You might see professional athletes needing to consume huge quantities of food to keep up with their training requirements, but that is their job, they are training many hours daily, and when they’re not they eat less. 

For the average person, that might spend an hour or so in the gym a few times a week, even every day, the calories burned do not constitute the need to eat more, or create a large dieting deficit. As a very vague estimate an average person would burn approximately 100 calories per mile of running, so a 5km (3 mile) run equals around 300 calories which in terms of food is an extra couple of slices of toast with butter – not much is it. 

In fact, some research shows that unless you are following a calorie-controlled diet considering calories in relation to exercise is actually detrimental to weight loss. I might think to myself I’ve been for a run this morning so tonight I can eat whatever I want = takeaway pizza and cookies. Actually, my pizza and cookies equate at least double the calories I burned running 10k (6 miles)! Depending on what I ate for the rest of the day it is likely I will therefore, not be in a deficit. 

Disclaimer: Eating pizza and cookies once in a while is great, this isn’t about demonising foods. It is explaining that mindset of exercising to eat more usually leads to at best weight maintenance at worst weight gain. 

Exercise for the right reasons

It might sound like I’m saying it’s not worth exercising. Well, that’s not what I am saying at all! There are many great reasons to exercise including: 

  • Physical health benefits
  • Body shape and composition
  • Boosts mood
  • Makes you more productive
  • Social activity 
  • Improved sleep 

Physical Health & Exercise

Exercise contributes to improved physical health and longer life expectancy. Regular exercise causes changes in many of the bodies systems including the cardiovascular system, nervous system, musculoskeletal system and endocrine system that can help to keep you fit and healthy and free from disease. Regular exercise reduces the risk of many of the deadliest diseases that are plaguing modern society including:

  • Cardiovascular disease (including heart attacks and strokes)
  • Some cancers
  • Type 2 diabetes
  • Osteoporosis and other musculoskeletal ailments

Doing both aerobic (cardio based) exercise and resistance training will help to reduce the risks of developing a wide range of diseases. You can find out the benefits of Cardio V strength training in this recent blog post

Body Shape and Composition 

While a calorie deficit is the best way to ensure weight loss if that is what is required, regular exercise can contribute toward maintaining a healthy weight and fat loss. Exercise, specifically resistance training, will also help to build (tone) muscle for a shapely body when you reach your desired weight. It is recommended that adults undertake resistance training 2-3 times per week in addition to the recommended 30 minutes 5 times per week for aerobic based exercise. Personal training can help with planning your exercise sessions, particularly for an effective resistance training workout that supports your progress in any other sport or training that you participate in. 

Exercise and Mental Health

Regular exercise has been found to have a protective effect for mild to moderate depression. Exercise can boost mood, and even prevent the need for medication in some cases. 

Happy lady running

“I regret that workout” … said no one ever

You might not feel like working out, you might have to give yourself a good talking to get going, but how many times have you exercised then regretted it? The release of hormones (endorphins) from physical activity promotes a feeling of wellness, happiness, increased energy and positivity. Exercise that is outside such as cycling or walking in nature, or workouts performed with others such as a game of tennis often increase the positive effect on mental health. However, the most important factor is participating in a form of exercise that you find enjoyable. 


In the busy lives that we all lead it is easy to say I haven’t got time to exercise. However, taking the time out to exercise can actually make you more productive. Time spent doing something you enjoy, as well as the release of hormones and resulting burst of energy can actually boost productivity. Some businesses are giving employees time to work out, or installing gym facilities inside workplaces as part of measures to increase staff satisfaction and productivity. 

Social Activity

Women taking part in a group fitness class

Exercise can be a lone activity, and sometimes this is just what you need. A run alone can help to clear the mind and boost your mood, but for many people the social aspect of exercise is what keeps them coming back. Joining a group activity whether that be a game of squash with a friend, a fitness class, a running group, football team or rugby club has many benefits. Making sport social means you are more likely to keep doing it, it can be hard to motivate yourself but most of us don’t like to let other people down so we show up. Team or club-based activities also have the added bonus of giving you an opportunity to meet new people, make new friends or even meet a partner with similar interests to yourself; this leads to social activity outside of the sport that further enhances your overall health and wellbeing. 

Improved Sleep

Lack of sleep plays a big part in deteriorating physical and mental health for many people; exercise can help us to sleep better and therefore, help to combat some of the physical and mental health problems that occur due to lack of sleep. Exercise can boost serotonin levels; this is a hormone that is involved in regulating the internal body clock. People that exercise tend to get more higher quality as well as longer sleep. Feeling refreshed after a good night’s sleep can help to combat stress and low mood, people that are not stressed in turn tend to sleep better. 

You do need to consider the timing of exercise though, as working out right before bed could have the opposite effect. Endorphins released during exercise can actually keep you awake; it is therefore recommended to finish your session at least 1-2 hours before turning in for the night. A warm bath and soothing drink after your session and before climbing into bed can help you to wind down and prepare for a good night’s sleep. 

There’s More to exercise than burning calories 

When working out to burn calories to lose weight, what happens when you hit the magic number on the scale? Unless you enjoy it, you’ll probably stop. For many people exercise and eating well go hand in hand, so if you stop working out you also stop being mindful of your food intake; this results in weight regain. Yoyo dieting. 

Exercise can most certainly contribute to weight loss, but exercising to burn calories is not the way to go. Exercise because you enjoy it, and because it contributes to an array of other benefits including enhancing your physical and mental wellbeing, reduces stress and increased productivity, and helps you to sleep better. Finding a form of exercise that you enjoy is the most important factor, this will ensure that you keep doing it. If you enjoy something the number on the scale, the weather, other life stressors are less likely to impact your desire to exercise. 

If you need help to get started, are interested in 1-2-1 or online personal training, or would like to incorporate some resistance training into a cardio heavy routine contact me. I always provide a free no obligation consultation, so take the first step to finding a path to health and fitness that is enjoyable and sustainable for the long term.

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