I will use mine when I do my Prowler Pull / Pushes and my Farmers Walks.
I usually go as hard as possible for 50 meters on either of those, and when
my heart rate returns to 65% of maximal, I hit up the next lap.
I do a Heavy Hard day followed by an easier speed day. I do this twice per week.
Usually in the morning about 6am. I then lift in the evening about 6 pm.
So it looks like this. Sat/Sun on, mon off, tues/ wed on, thr/ fri off.
Seems to work well, with enough recovery.
I will use the HRM first thing in the morning to monitor if my HR has returned to normal,
if it has not, i will usually back off a bit that morning and evening.