Yes, it is scientifically accurate to say that humans burn calories when they exercise. The human body requires energy to move and function, and this energy comes from the food we eat. Our bodies store excess energy or calories from food as fat. During exercise, our muscles use this stored energy to contract and enable movement. The more intense the exercise, the more calories or energy used.
How does exercise burn calories?
Exercise burns calories in a few key ways:
Muscle contractions
Our muscles require energy to contract and relax. The harder and more frequently they contract during exercise, the more energy or calories they use up. Weight training, sprints, and high-intensity interval training require powerful and frequent muscle contractions, burning more calories than lower intensity exercises.
Increased heart rate and breathing
When we exercise, our heart rate rises to pump more oxygenated blood to our working muscles. Our breathing also quickens. This increased heart rate and respiration uses energy and burns calories. More vigorous exercise leads to a higher heart rate and metabolic rate, burning more calories.
Increased body temperature
As we workout, our muscles generate heat, causing our core body temperature to rise. It takes energy and calories to produce this heat. Intense exercise can significantly raise our body temperature, burning more calories in the process.
Afterburn effect
After exercise, our body continues burning extra calories for hours or even days later. This is called excess post-exercise oxygen consumption or the afterburn effect. Intense exercise causes the most significant afterburn. Your body burns extra calories after exercise replacing muscle glycogen, repairing muscles, and returning to a resting state.
How many calories does exercise burn?
The number of calories burned during exercise depends on:
Exercise intensity
Higher intensity exercise burns the most calories per minute. High intensity interval training can burn over 25 calories per minute. Moderate exercise like brisk walking may burn around 7 calories per minute.
Exercise duration
The longer you exercise, the more calories burned overall. Exercising for 60 minutes will burn more total calories than 30 minutes.
Muscle mass
More muscle requires more calories, so those with greater muscle mass burn more calories when exercising. Weight training helps build muscle.
Body weight
Heavier individuals burn more calories than lighter people when exercising at the same intensity. A 155 pound person may burn around 10 calories per minute during moderate cycling, while a 185 pound person may burn 12 calories per minute.
Metabolic rate
Someone with a faster metabolic rate and more metabolically active tissues like muscle burns more calories during the same exercise than another person.
Exercise efficiency
The more efficient you are at an exercise, the fewer calories you burn. Experienced cyclists burn less calories cycling than beginners at the same speed.
| Exercise | Calories burned per 30 minutes for 155 lb person |
|---|---|
| Low intensity cycling or walking | 120 |
| Moderate intensity jogging | 295 |
| High intensity sprinting or swimming | 400 |
| Vigorous aerobic dancing | 330 |
| Heavy weight lifting | 112 |
How does exercise promote calorie burning?
Exercise promotes calorie burning through:
Increasing muscle mass
Lifting weights builds metabolically active muscle tissue. The more muscle you have, the more calories you burn daily. Adding 3 pounds of muscle can burn an extra 120 calories per day.
Afterburn effect
The afterburn effect from intense exercise boosts calorie burning for up to 48 hours after working out. High-intensity interval training maximizes afterburn.
Increasing metabolic rate
Vigorous exercise temporarily increases your basal metabolic rate (BMR). Your BMR is the number of calories you burn at rest for basic functioning like breathing and circulating blood. Exercise trains your body to burn calories more efficiently.
Improving workout capacity
As your fitness improves, you can exercise harder and longer. This allows you to burn more calories per workout. Improved cardiovascular fitness also helps you burn calories more efficiently during exercise.
Building mitochondria
Exercise causes muscle cells to produce more mitochondria. These are the energy factories in your cells that burn calories. More mitochondria means more potential to burn calories.
What types of exercise burn the most calories?
The types of exercise that burn the most calories include:
High-intensity interval training (HIIT)
HIIT involves short bursts of maximum effort followed by brief rest periods. Sprinting, cycling, jumping rope, and kettlebell circuits are effective calorie-torching HIIT workouts.
Sprinting
All-out sprinting is one of the most intense calorie-burning exercises. Just a few 60-second sprints can burn over 100 calories.
Jumping rope
Vigorously jumping rope in intervals can burn well over 10 calories per minute. Ten minutes of fast rope jumping may burn more calories than 30 minutes of jogging.
Kettlebell training
Full body kettlebell circuits keep your heart rate high. Kettlebell swings, cleans, and snatches burn up to 20 calories per minute.
Rowing
Rowing works most major muscle groups and gets your heart pumping. Thirty minutes of vigorous rowing can burn over 300 calories.
Stair climbing
Climbing stairs engages your legs, glutes, and cardiovascular system. Running up stairs burns more calories than jogging or cycling.
Burpees
These full body plyometric exercises burn over 10 calories per minute. Ten minutes of non-stop burpees can torch 150 calories.
Does weight training burn calories?
Yes, weight training definitely burns a significant amount of calories. Lifting weights burns calories by:
Activating muscle fibers
When you lift weights, you activate muscle fibers. Activating more muscle fibers requires energy and burns calories. Using heavier weights activates more fibers.
Increasing metabolism
Weight training increases your resting metabolic rate for up to 48 hours after your workout as your body recovers and repairs muscle tissue. More metabolism equals more calorie burn.
Promoting afterburn
The afterburn effect from resistance training can boost your calorie burn long after you leave the gym. Weight training afterburn comes from rebuilding muscle fibers.
Building muscle
Since muscle is metabolically active tissue, adding more muscle mass by weight training ultimately leads to burning more daily calories. Lifting progressively heavier weights builds more muscle.
While lighter weights burn fewer calories per session than intense cardio, the calorie burn adds up over time as you build more muscle and your metabolism increases. A mix of weight training and cardio is ideal for maximum fat loss.
Do calories burned equal fat loss?
Burning calories through exercise does not guarantee equal fat loss. Here is why:
Calorie intake matters
If you burn 300 calories exercising but then eat an extra 400 calories, you are unlikely to lose fat because more energy was consumed than expended.
Calorie quality is important
100 calories from a donut is processed differently by your body than 100 calories from chicken breast and broccoli. Whole, nutrient-dense foods promote fat loss.
Water weight fluctuations
Intense exercise causes water retention in the muscles which masks fat loss on the scale temporary. Fat loss occurs beneath the water weight.
Lean mass gains hide fat loss
Building muscle from weight training can hide fat loss. The scale weight stays steady as muscle and fat changes in composition. Use tape measurements or body fat testing to assess fat loss along with the scale.
Initial rapid weight loss is not all fat
When starting a diet or exercise program, initial rapid weight loss is often water, glycogen, and waste loss, not pure fat loss. Fat loss occurs more steadily over time.
For the most fat loss, create a calorie deficit through diet and exercise, while lifting weights, eating whole foods, staying hydrated, and tracking body composition periodically. Patience is required.
Conclusion
In summary, it is absolutely scientifically accurate to state that humans burn calories when they exercise. A wide variety of aerobic and resistance exercises burn substantial calories by activating muscles, increasing metabolism, and promoting the afterburn effect. The number of calories burned depends on the exercise intensity, duration, muscle mass, and training status. While exercise burns calories, optimal fat loss relies on also maintaining a calorie deficit through diet and tracking body composition rather than just the scale. To maximize fat loss, a combination of vigorous cardio, weight training, and a nourishing whole food diet works best for most people. Consistency with both diet and exercise is key to seeing results over time.
