I recently re-read through the conditioning FAQ and didn't see a direct answer to this, so I'll put the question here. For LISS conditioning and building a cardio base, is it better to walk at a higher speed or jog at a lower speed? Or as long as you keep your heart rate up and keep moving for the same amount of time is it irrelevant which you do? For instance, I just walked for 45 minutes @ 3.3mph, but if I were to jog at that speed, I'd be switching back and forth to walking to keep going for the entire time. So should I just keep walking and increasing the speed until I have to jog (since my heart rate is somewhere above 120), or lower the speed til I can jog the whole time and then increase the speed?