What is a MET?
MET stands for Metabolic Equivalents. It is an index of energy expenditure through "the ratio of the rate of energy expended during an activity to the rate of energy expended at rest." Sitting at rest is defined with a value of 1. You can find MET values for 800+ activities here.
Calories per minute = 0.0175 × MET value × body weight in kg
which is equivalent to:
Calories per minute = 0.007937866475 × MET value × body weight in pounds
which is roughly:
Calories per minute = 0.008 × MET value × body weight in pounds
a marginal 0.78% increase from the real value.
What is EPOC?
EPOC stands for Excess Post-Exercise Oxygen Consumption and is commonly called the Afterburn Effect by most athletes. "On termination of exercise, oxygen consumption (VO2) will gradually return toward baseline levels in an exponential manner, first demonstrating an initial rapid component followed by a slow, longer component." "The overall VO2 that is consumed above resting values during this phase is referred to as the excess post-exercise oxygen consumption." In "1984, the term EPOC was coined to better represent the multiple factors that contribute to elevated post-exercise metabolism."
"EPOC comprises two phases: the rapid and slow phases. The duration of the rapid phase generally lasts approximately 2 to 3 minutes but may extend out toward 30 to 60 minutes and primarily involves:
• restoration of the phosphagen system
• removal and reconversion (oxidation) of lactate
• reloading hemoglobin/myoglobin with oxygen."
"The slow phase lasts longer, depending on the magnitude of tissue stimulation (repair and adaptation) and the amount of recovery needed, and includes:
• continued thermoregulation
• increased heart rate and ventilatory demand for anabolic processes
• increased metabolism because of tissue repair and synthesis, and glycogen synthesis
• residual effects of circulating sympathetic hormones (e.g., catecholamines)
• removal of accumulated carbon dioxide remaining within body tissues."
"Exercise intensity and exercise duration contribute most notably to the magnitude of EPOC. Overall, it has been concluded that exercise intensity has a greater role in EPOC variability compared with exercise duration. In other words, the higher the intensity of exercise, the greater the magnitude of the EPOC, which translates into a greater number of calories expended."
"EPOC generates approximately 7% of the total energy expenditure of exercise." Although "EPOC may be limited in its contribution to weight loss, there may be a role for it in terms of energy balance (i.e., weight maintenance). It has been suggested that the cumulative effect of the EPOC over a 1-year period may be the energy expenditure equivalent of 3 lb of adipose [(fat)] tissue."
After adding up the calories burned, using MET values over a certain time, multiply that number by 1.07 to estimate the total calories burned by the workout.
American Council of Exercise - Exercise Physiology, pg. 112-113