Whether you’re burning them or consuming them, most people are aware of calories and their role in weight management, but have you ever wondered which exercise burns the most calories? Could a sweaty session on one of the best treadmills be the answer, or hitting the yoga mat for a HIIT workout? Unsurprisingly, it’s more intense workouts that use several different muscle groups that will ultimately burn more calories - like cycling - but the key is finding the right solution for you, and understanding what you’re trying to achieve.
As such, first it’s important to understand what a calorie actually is, how calorie burn is measured, and the factors that will determine how energy-intensive a given activity is.
For the answers, we spoke to Dr Javier Gonzalez, an associate professor in Human Metabolism at the Department for Health at the University of Bath.
What is a calorie?
While we can find calories everywhere we look, from the best fitness trackers to the back of food packets, the actual definition of the term is often lost in translation.
A 2006 article on the "history of the calorie in nutrition", published in The Journal of Nutrition, details how the calorie began as a unit of heat in France during the 19th century.
"A calorie is a unit of energy," says Dr Gonzalez. "Specifically, a calorie is the amount of energy required to heat one gram of water by one degree celsius (at a standard atmospheric pressure)."
Javier Gonzalez earned his PhD in Human Nutrition and Exercise Metabolism in 2010. He currently works as a senior lecturer at the University of Bath. His research interests focus on human fuel use; he received the Julie Wallace Award in 2018 in recognition of his work. He also serves on the editorial board of The Journal of Physiology and is an Associate Editor for the International Journal of Sport Nutrition & Exercise Metabolism.
It wasn’t until the 20th century that it became entrenched in US popular culture as a unit of energy used when speaking about nutrition.
"In nutrition, we commonly measure the energy in food in kilocalories (kcals). For example, an average person in the UK might consume between 2000-2500 kcals per day," Dr Gonzalez says.
The number of calories a person will need each day will depend on several factors, including their age, height, build and activity levels.
How calories are measured
As well as referring to energy coming into the body by way of food and drink, we also use calories as a way of quantifying energy expended through basal metabolic rate, NEAT and exercise. There are several methods of measuring this.
"The gold-standard laboratory measure involves sitting people in a room which measures the amount of heat they produce (known as direct calorimetry), but there is reported to only be one working direct calorimeter in the world currently," Dr Gonzalez says.
"The gold-standard measure under free-living conditions is a technique called doubly-labeled water, in which people drink a special water where the hydrogen and oxygen atoms in the water are 'labeled'. Measurements of these labeled hydrogen and oxygen are taken over a period of one-to-three weeks, and these can tell us the amount of carbon dioxide we have exhaled on average over that time period.
"This can be used to estimate total energy expenditure (calorie burn). Other methods include directly measuring the amount of oxygen we consume, or estimating movement with accelerometers and heart rate monitoring."
Heart rate and movement monitoring is how the best fitness trackers provide an estimate of your calorie burn during certain activities. These figures can be useful for giving you a rough idea of your total daily energy expenditure, but they tend not to be very accurate.
Factors that impact calorie burn
"The main factor that impacts our calorie burn at rest is the amount of muscle mass we have," says Dr Gonzalez.
“When we exercise, the main factor then becomes the intensity and type of exercise. For example, exercises which use more muscle groups result in more calories being burned than those involving fewer muscle groups.
“In addition, the more vigorous the intensity, the more calories we will burn. This is mainly limited by our fitness, so the people who can burn the most calories per minute are the elite endurance athletes."
Which exercise burns the most calories?
Carrying on from his points above, Dr Gonzalez says the types of exercise that burn the most calories are intense activities that involve multiple muscle groups in the upper and lower body.
"Typically, whole-body exercises that involve weight-bearing and get us out of breath the most will burn the most calories, so running is probably the best example."
A report from Harvard Health Publishing went one step further, producing a chart containing the approximate calorie burn for 80 exercise methods, from gym activities like weightlifting, circuit training and stationary cycling to sports including football, soccer and running. There are also 18 outdoor activities and everyday tasks such as sleeping, cooking, gardening and mowing the lawn included in the list.
The estimated calorie burn of taking part in the activity for 30 minutes has been calculated for a 125-pound, 155-pound and 185-pound person using the University of Rochester Medical Center Calorie Burn Rate Calculator and the Ace Fitness Physical Activity Calorie Counter. Several of the activities also show different figures depending on a specified intensity.
Of the activities listed, cycling at 20mph burned the most calories in 30 minutes. A 125-pound person would burn approximately 495 calories, a 155-pound person would burn 594, and a 185-pound person would burn 693, the Harvard Medical School article states.
This high-speed bike ride was closely followed by running at 10mph, with 453 calories, 562 calories and 671 calories respectively. So, it’s no wonder treadmills and stationary bikes feature on our list of the best exercise machines to lose weight.
Among the gym activities calculated, vigorous stationary cycling (on one of the best exercise bikes) had the highest figure, with a 185-pound person burning an estimated 441 calories in half-an-hour. Meanwhile, the most energy-draining outdoor activities were chopping wood and shoveling snow – both burning 252 calories during 30 minutes of work.
How many calories should you eat to lose weight?
One of the most common conversation topics to center around the calorie is weight loss. This is because we can use the number of calories we consume against the number of calories burned each day to determine our energy balance.
“The main determinant of body weight in the long term is energy balance," says Dr Gonzalez."If calorie intake is lower than calorie expenditure (often referred to as a calorie deficit) then we will lose weight in the long-term."
It would seem logical, then, for anyone looking to lose weight to choose the most efficient calorie-burning activity possible when exercising. However, there are several further factors to consider, such as diet and activity levels outside of the gym.
"It is possible that the amount of calories burned during exercise could be offset by increased calorie intake," says Dr Gonzalez. Or, in other words, as we exercise more our appetite and consequent calorie consumption increases.
He adds: "In general, exercise isn’t very effective for weight loss, but it does seem to help in preventing weight regain after weight loss."
A 2015 study published in the Progress in Cardiovascular Diseases journal found: "Substantial weight loss is unlikely to occur from a physical activity program unless the overall volume of exercise training is well above the minimum recommended levels." So the amount of exercise required to create a calorie deficit when working against a consistent diet could be too time-consuming for most people.
Dr Gonzalez encourages people to exercise for the multitude of health benefits it offers outside of weight management:"For health, it would be beneficial for people to include a wide range of exercises to gain the specific benefits that each can bring. For example, aerobic-type exercise like running can improve the health of the heart and circulatory system, whereas strength training can improve our general physical function and the health of our bones, tendons and muscles."
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Harry Bullmore is a fitness writer covering everything from reviews to features for LiveScience, T3, TechRadar, Fit&Well and more. So, whether you’re looking for a new fitness tracker or wondering how to shave seconds off your 5K PB, chances are he’s written something to help you improve your training.
When not writing, he’s most likely to be found experimenting with a wide variety of training methods in his home gym or trying to exhaust his ever-energetic puppy.
Prior to joining Future, Harry wrote health and fitness product reviews for publications including Men’s Health, Women’s Health and Runner’s World. Before this, he spent three years as a news reporter with work in more than 70 national and regional newspapers.