Unplanned Time Off

Woke up Tuesday w/ a bad sore throat and some serious congestion.  Probably wouldn't have held me back much, but I also had some pain in my left knee.  Running on some hard surfaces through the holidays back on the East Coast I had been in a bit of an ice+ibuprofen post run routine for the past 2 weeks.  I told myself that if the mild discomfort in the knee got any worse, I was going to take a few days off.  So on Tuesday morning w/ the knee bothering me a bit and the awful cold, it was an easy decision to take a few days off. . .

Today, was the first day back.  The next workout was scheduled to be the Threshold running and being that it's the "miles" that bother my knees, never the "pace" - a low mileage day on a soft track seemed like as good a place as any to get back into it.  

First thing I noticed prior to the run was that my resting HR was a good 5 beats/min higher than normal.  I imagine this has to do w/ my still being a little sick and probably somewhat dehydrated.  I figured there was a good chance I'd need to cut the workout short, I just hoped that the knee was OK.

My current T-pace is about 6:16/mile, but I usually run these workouts on feel and adjust if I'm off the pace by too much.  The plan was to run three 2-mile repeats at about 12:32 w/ 2-minute breaks between each 2-mile interval.  

Thankfully the knee was fine through warmups and the first 1/2 mile of the first interval felt good.  Took a look down at the watch and saw a 5:56 pace - too fast.  I did my best to slow down, but it really just felt easy - I figured this was due to the fresh legs.  I relaxed the pace to 6:08 and everything felt great.  Then I took a look at my HR to see that it was again 5 beats/min above normal.  This seemed strange to me because typically my breathing is a bit heavy if my HR gets up that high, but it felt like a normal T-run today.  Was my HR up because I'm sick?  Should this have been expected because my resting HR was up 5-beats/min?  Or was it because the pace was a little faster - and if this was the case, why didn't it "feel like" I had a higher HR?  If I was a more experienced runner, I guess I'd know the answer.  I decided to just let it go, and continue the run on feel.  I finished the first 2-mile at 12:15.  

Second repeat - same thing.  HR climbed faster and higher than normal, but I didn't feel as if I was putting in that kind of effort.  At this point, I became concerned that this workout simply wasn't accomplishing what it was supposed to do, - I'm either stupidly going too fast (but it didn't feel like it), or my sickness is somehow causing a higher HR than normal for a given effort level.  Rather than run a 3rd set at the wrong HR, or slow down to where it felt like I wasn't getting the proper work in (and also considering the knee), I stopped after the two intervals were completed.

When I got home I checked this workout against previous ones, and sure enough - my HR was 5-6 beats higher for a given pace than it was last week.  I guess the good news was that the pace "felt" like it had the prior week - the HR was just different.  So that begs the question - when you're running a Threshold workout and the HR is just high that day do you A) cut the pace back that day to get the HR to the proper percentage of max-HR, or do you B) forget the HR for that day and run the workout at the pace that feels correct? 

Training:  5 miles (including warm up) Two 2-mile repeats @ 6:08/mile pace w/ 2-min break.