Last day I went (Sunday) was on a single track hiking trail. 70 #'s, 2.69 miles, only about 340' of up and down, and it took 49m 16s. Don't wear a monitor but probably should.You don't specify the intensity of your rucks, but I suggest dropping one of the ruck days and opting for an unloaded walk or another form of zone 2 cardio to enhance your recovery.