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.
For example, a 160-pound person will burn 157 calories walking at a 3.5-mph pace for 30 minutes on a treadmill, while running at a 5-mph pace burns 303 calories for a person of the same weight exercising for the same duration, according to MayoClinic.com. The Road to Weight Loss.