i wish i could see how fast you were jogging/running. its really not about how much ground you cover, so even if you only ended up going for a total of 3 to 3.5 miles (instead of 4-4.5 at your current rate), but you kept a slow, steady pace w/in your target rate, you should be fine

the only reason i say this is b/c like you said, its your entire body. i think you may be pushing too hard? :dunno: try to slow it down to a trot and check your heart rate. of course, try to keep good form and minimize crazy bouncing, which could happen from a slower pace