Our bodies are an amazing machine. They have the ability to take in energy and utilize this energy. The energy that a body utilizes is termed a calorie. A calorie is a unit of energy that when burned raises the temperature of 1 kilogram of water by 10 Celsius. From a clinical standpoint, we are able to measure the body’s energy expenditure in 3 ways. The first is called Resting Metabolic Rate (RMR) which is literally our body at rest and the amount of energy used to keep it functioning. Approximately 65-75% of our daily calories is burned this way. The second way is by the Thermic Effect of Food (TEF) which is the amount of energy our body uses to consume foods. Approximately 5-10% of daily calories are used for this. The last means of calorie expenditure is by Physical Activity Energy Expenditure (PAEE) which causes a varied amount of calories burned based upon a person’s above normal physical activity level. Each of these measures equate to the sum total of calories used on a daily basis. If you take in more calories than are used, that translates to excess fat deposits and increased body weight. If you take in fewer calories and are active, you lose body weight. It’s a tipping the scale kind of challenge.
If you are on an exercise program or not, a question you may have not asked is, “What happens to caloric expenditure during and after exercise?” To answer that question, it is important to understand that there is a lot of variability in each of us when it comes to burning excess calories throughout the day. During exercise sessions, a person can train in various ways to achieve different caloric burns. Cardiovascular and strength training and the different training protocols within each category, promote different energy outputs. Basically, the more stress placed on the body, outside of normal activity, it forces the body to metabolically respond feeding soft tissues with nutrients so they can perform the desired work. This concept is of vital importance especially after an exercise session when the body is at rest.
After an exercise session, be it cardio or strength training, the body does not instantaneously go back to its pre-exercise state. The resting metabolic rate is now elevated. In truth, these levels can stay elevated for a few minutes up to a few hours post exercise (depending on exertion and type of movement) which is important for those seeking weight loss or have specific dietary monitoring needs.
Cardiovascular training not only conditions the heart and lungs also are a great way to burn calories. For example, if a person walks for 30 minutes at a moderate pace, they could burn an additional 10-30 calories post-exercise!
Strength or resistance training has been found to be even more effective for post-exercise calorie burn. This form of exercise can help keep the number of calories burning for hours due to the need for muscle tissue repair and growth which require more energy to function.
One of the most important ideas to remember about calories and the human body is that quantity and quality of food intakes will help the body work more efficiently. Already fatty foods will just add to unwanted weight and force the body to slow down diminishing energy levels. Discussing your diet with your doctor or a nutritionist or even an exercise professional is a great way to further understand two things: how to have an effective exercise routine and what is the proper amount of foods to ingest to have the best caloric balance for your daily life.
Written by Craig Cole, Bethany Village Exercise Physiologist