Into a higher gear. A new record by six seconds, LOL.

2 flights of stairs x 50 trips up and down
Time: 25:40
Heart Rate: 170. 170 is high, but you kinda have to expect it when pushing a record time.

It fell apart in the second half. If I'd been able to maintain the pace of the first half, the time would have been 24:40. No point in pushing to the point of having to stop and gasp for breath though, that makes for an even worse time.