The basic answer: physical activity and exercise burns calories. There are many different types of exercise. Incorporating all of them into your daily routine will create a well rounded workout that will help you reach your fitness goals.
Your weight is determined by the relationship between how many calories you eat and how many you burn. Eating more than you burn is known as a calorie surplus and leads to weight gain. Burning more than you eat is known as a calorie deficit and leads to weight loss. Regardless of your weight goals, exercise and burning calories are required to reach them.
Your body is always burning energy, even when you are doing tasks that seem unrelated to exercise such as eating, reading and even sleeping. Your body burns energy to power your brain, digest food and keep your heart beating. In addition to keeping you alive, exercise and physical activity both make up a huge chunk of your daily energy expenditure. Exercise and physical activity are the only two ways you can significantly increase how many calories your body burns each day. You can estimate your daily energy needs by using the calorie calculator.
Types of Exercise & Physical Activity
There are different types of exercise you can use to burn calories, each having a slightly different effect on the body. The three main types of exercise are: strength training, cardiovascular and high intensity.
Strength training's main purpose is building muscle. Strength training includes lifting weights (free weights or machines) or using body weight exercises (push-ups, sit-ups, pull-ups) to build muscle. Though strength training is not thought of as a calorie burning exercise, it should be used in conjunction with any weight loss strategy. Strength training can also increase bone density which can prevent osteoporosis.
Muscle is a very high maintenance tissue; it takes a lot of energy to keep it alive. You will burn more calories throughout the day (even at rest) by building more muscle. Take two scenarios: person A is 160 pounds and has a body fat of 5%, person B is 160 pounds but has a body fat of 20%. Person A has a lot more muscle and therefore burns a lot more calories throughout the day, even when they are not exercising. This is because person B's fat tissue does not burn nearly as much energy as the muscle on person A. You can speed up your metabolism by building more muscle.
Cardiovascular exercise is any workout that gets your heart rate up for an extended period of time. Cardio is good at burning large amounts of calories and aiding in weight loss. It also has health benefits (lowering blood pressure/cholesterol levels) and shouldn't be ignored, even by those trying to gain muscle. Examples of cardio include running, swimming, biking and playing most sports.
High Intensity Training
High intensity training (HIT) is a hybrid between strength training and cardio. HIT uses strength training exercise with little or no rest between sets. Because there is little or no rest between sets, your heart rate remains high throughout the entire workout. HIT can save you time by combining elements of both types of exercise. Instead of doing strength and cardio separately, HIT lets you do them together. An example of HIT is Crossfit.
Use the SH Trainer for help creating an exercise routine.
The Bottom Line
Your body is always burning calories. The only way to meaningfully increase your energy expenditure and improve your overall health is by exercising on a regular basis. There is no "best" type of exercise. All forms of exercise have unique health benefits. A well rounded routine will help you achieve your goals in the healthiest and quickest way.