LGO mm's answer is good but not complete......

Normally, we are doing aerobics except if we are sprinting(running 100m at maximum speed... or running away from danger... hehee), or doing weight training. We could not last long doing anaerobics. Our muscle has limited carbohydrate storage so we will switch to fat as energy source if we continue to run. Carbohydrate will be burned thru 三羧酸循环 and fatty acid thru beta-oxidation. Both process needs oxygen.

The point is, if we are running for >5 min, you are doing aerobics for sure...... don't worry... keep running, caine!!