Definition of organism for English Language Learners. : 1  an individual living thing. : 2  a system with many parts that depend on each other and work together.
Figuring out how many calories you burn when running is, on a simple level, a fairly straightforward calculation. Most experts (and lots of studies) suggest that a person of average weight burns about 100 calories in a mile of running.
When it comes to walking or running, people tend to burn between 80 and 100 calories per mile, no matter how fast or how slow they are. Half an hour of walking at a casual, walking-the-dog pace (2.5 mph, or a 24-minute mile) will burn about 97 calories. A brisk 4-mph stroll (15-minute miles), on the other hand, will burn about 161 calories in 30 minutes.