If you’ve ever taken a group exercise class where each participant’s heart rate and projected calorie burn are shown on a screen, you are aware of how much these numbers fluctuate from person to person. Additionally, you may have noticed that men often burn more calories than women. But have you ever questioned why, even during the same workout,how many calories do I burn in a day?
The mechanisms in your body that break down nutrients for energy, support growth, and other purposes are collectively referred to as metabolism. However, metabolism is anything but straightforward.
According to Anya Rosen, RD, a virtual functional medicine practitioner based in New York City, “there is a constant ebb and flow of reactions that build or repair our body (anabolism) and responses that break down food and energy stores for fuel (catabolism).
It is a really difficult subject to research because of how intricate it is, she continues. Your current rate of calorie burning depends on a number of variables. Here are the top six factors, according to scientists, that affect how many calories you burn while exercising.
1. Body Mass
Kyle Gonzalez, a qualified strength and conditioning specialist and performance coach at Future with a San Francisco basis, states that in general, the more weight you have, the more calories you’ll burn every session.
The more weight you have, the more energy it takes to move your body because calories are merely a measure of energy. In other words, if two persons have differing weights, the person who is heavier will burn more calories since they expend more energy when they move.
Larger internal organs (such as the heart, liver, kidneys, and lungs) are more common in people with larger bodies, which has an impact on how many calories are used during exercise and at rest. These organs and their processes demand energy.
According to one study, variations in internal organ size can account for up to 43% of the variation in total calories burned among individuals.
One of the many reasons why losing weight is difficult is that your body burns fewer calories as you lose weight, which can result in a weight loss plateau or even weight gain. However, it’s not the only explanation.
According to a recent review, losing weight can also result in other physiological changes, such as the body’s propensity to burn stored fat for energy (a process known as fat oxidation), increased ghrelin levels, which increase appetite, and decreased leptin levels, which decrease satiety.
Consider working with a registered dietician who specialises in weight reduction to help you reach your goal in a healthy and sustainable way if you’re trying to lose weight but have reached a plateau. Visit the Academy of Nutrition & Dietetics to locate one.
2. Size of muscles
This is when it becomes a little bit more challenging. If two people have the same weight but have different amounts of muscle, the person with greater muscle will burn more calories. According to Jenaed Brodell, RD, a specialist sports nutritionist with a private practise in London, “Muscle tissue burns more calories than fat tissue.”
However, estimates of how many calories a pound of muscle will burn are sometimes grossly exaggerated. According to data, a pound of muscle burns roughly five calories per day, compared to two calories per day for a pound of fat.
Because your body needs more energy to support the greater pace at which your muscles are contracting during exercise, having more muscle mass will raise your total calorie burn. To cut a long tale short, think about boosting up your strength-training routine if you want to increase your calorie burn.
According to Brodell, “Evidence shows that lifting weights burns more fat [than cardio exercise] and has more promising long-term results.” However, she adds that because everyone has different goals and physical limitations, it is ultimately up to you to decide how you exercise.
Additionally, remember that exercise is beneficial for your health in general whether or not you lose weight. According to an analysis that appeared in iScience in October 2021, regardless of weight, higher cardiorespiratory fitness is linked to better health outcomes and a lower risk of early death, even if increased exercise rarely results in long-term weight loss.
According to Gonzalez, males generally burn more calories both at rest and during exercising than women do. But there’s nothing mystical about the reason for this; it’s just that men are typically bigger and have more muscle mass than women of the same age and weight.
At rest, men typically burn 5 to 10 percent more calories than women do, and this difference typically rises with exercise, according to Gonzalez.
Additionally, despite the fact that women can definitely increase their muscular mass through strength training, physiological distinctions prevent them from generally being as thin as males. According to Brodell, women are genetically prone to store more fat in order to promote hormone synthesis and pregnancy.
Body fat is also necessary for storing energy, safeguarding internal organs, and supporting vital processes including growth, immunity, hormone synthesis, reproduction, and metabolism, according to the National Institute of General Medical Sciences.
Men need between 2 and 5 percent of body fat, while women need between 10 and 13 percent, according to the American Council on Exercise (ACE). However, these bare minimums might not be adequate.
A healthy range for persons under the age of 40 is 8 to 20 percent for males and 21 to 33 percent for women, according to the most often referenced study on the subject, even though there is no official recommendation for the ideal body fat percentage. Nevertheless, the connection between health and body fat is nuanced and poorly understood.
Focus on the things you can control rather than worrying about how your birth sex influences your calorie burn. The final line, according to Gonzalez, is that both men and women should concentrate on increasing their muscle mass and cardiovascular fitness through a well-balanced cardio and strength-training regimen.
We often lose muscular mass as we get older, claims Brodell. You can start losing up to 3 to 5 percent of your muscle mass every decade after the age of 30. It’s unclear why this happens, but a review article from July 2017 in Ageing Research Reviews suggests that it’s probably because your body becomes less sensitive to hormones that support protein synthesis, which is essential for maintaining muscle mass.
Your metabolic rate, or how quickly you burn calories both at rest and while exercising, decreases as a result of this loss of muscle mass.
According to a study on human metabolism, which was published in the August 2021 issue of Science, metabolic rate may not fall throughout adulthood instead plateauing between the ages of 20 and 60 before starting to decline.
The doubly labelled water approach, the industry standard for this kind of assessment, was used by the researchers to gauge the energy usage of 6,421 men and women ranging in age from 8 days to 95 years.
However, this does not always imply that everyone’s calorie expenditure remains constant as they age. According to Rosen, who also notes that it’s impossible to precisely quantify metabolism, the study on daily energy expenditure over the span of a human life is “interesting, but it is not necessarily definitive proof that our concept of metabolism is erroneous.”
Additionally, not all of the numerous physiological changes brought on by ageing have likely been taken into account, not even by trained eyes.
Gonzalez claims that even if you cannot stop your body from ageing, consistent strength training can help you maintain or even grow your muscle mass. Strength training can help you raise your resting metabolic rate, which gradually increases the amount of calories you burn when at rest.
5. Level of Fitness
It becomes easier to perform a particular exercise the more often you do it. That’s not in your imagination, Gonzalez says; given time, your body does adjust to perform tasks more readily. This is a wonderful thing all around.
It implies that with practise, you may run farther or faster, and that with the right kind of exercise, your muscles would be able to lift more weight.
But it also influences how many calories you burn. Gonzalez asserts that as your body adjusts to exercise, you will burn fewer calories while still exercising. Your body becomes more efficient as you get fitter, from your lungs to your muscles to your heart to your brain.
Because of this, a beginner may burn much more calories than someone who has been performing the same exercise for years. Changing your exercise regimen can also improve your fitness level and calorie burn.
6. Exercise Intensity
Additionally, it’s likely that two people performing the same exercise aren’t actually burning the same number of calories. According to Brodell, someone exercising at a high intensity—which means they are breathing deeply and are unable to carry on a conversation—can burn twice as many calories as someone exercising at a low level in the same length of time.
Additionally, just because you are travelling the same distance or performing the same exercises as someone else does not imply that you are exerting yourself to the same degree.
According to the Department of Health and Human Services (DHHS), running and walking both lower blood pressure and lower your risk of developing chronic diseases like heart disease and type 2 diabetes.
However, a previous study found that adults who walked a mile burned about 89 calories while adults who ran a mile burned about 113 calories.
According to the DHHS, 150 minutes of low-intensity exercise each week is sufficient to produce a variety of health advantages, such as lowered anxiety, improved sleep, lowered blood pressure, greater cardiovascular fitness, and a decreased risk or slower progression of several chronic illnesses.
Adding more intense exercise to your schedule will increase your calorie burn and enhance these advantages. The ACE advises raising your speed, range of motion, or weight when performing strength-training exercises to increase the intensity of your workouts.
The main takeaway is to try to avoid worrying excessively about circumstances that are beyond your control. Finding forms of movement that you enjoy and feel sustainable is crucial because exercise has many advantages besides just helping you burn calories. According to Brodell, “the best kind of exercise for a person ultimately relies on that person’s goals, physical condition, and ability.”