Thanks for the reply!
I based it off of some estimation I did with cycling -
warm up for 15 min, goto a steady climb increasing while in the saddle every minute on the minute, then get out of the saddle for 15 seconds and check for peak heart rate.
The HRM is pretty close with measuring my pulse manually - it's a strap based one, not a fitbit, so it should be fairly accurate.
I mentioned it in passing to my physician a while ago, but if my resting heart rate is normal, I'm not really considered to have tachycardia so she wasn't too worried. I started running on-and-off about 1 year ago and much more regularly about 8 months ago, though only about 1-2 miles max for the most part. I bumped it up to 5-7 miles 2x/week about 2 months ago so I can start getting used to olympic triathlon distances. Admittedly, I haven't done any specific training except run at a pace where I can maintain a conversation just barely.
Level of fitness - I can swim about 1 mile without feeling tired afterwards at a 2min to 3min 100m pace with breaks every 500m, and do a sprint length duathlon (20km bike, 5km run) also without feeling tired afterwards...not terribly fast mind you, but I could probably maintain pace for 40km bike and 10km run as well judging by how I feel afterwards. I lift 3 days a week, run/bike 2 days a week (combined), and swim once every week to every other week.
Yeah I know very little of cycling or swimming. I still wouldn't be shocked if you underestimated your max HR a bit and if your HRM overestimates things a bit too. If I were you I'd get to a track, do a speed workout and see what happens to your HR (don't push TOO hard, don't want your death on my conscience
). There are pyramid workouts designed to push your HR to the max, but I don't think you necessarily need to worry with something too specific. Any solid series of short intervals (e.g. 30s fast, 30s slow, 6 to 8 reps, slow as slow as you want, fast as fast as you can while maintaining the same pace for all fast reps) should shoot your HR way, way, way beyond what it is at a pace that feels like jogging to you.
But yeah, that's only to dble check on your max HR. Anaerobic work doesnt necessarily do all that much to your aerobic capacities (warning: you'll read anything and everything online, this is just my opinion based on what I read and personal experience). It certainly helps a bit, but aerobic capacities improve most from aerobic work, long runs and tempo runs. Can't really tell what would work best for you specifically, but a mix of tempo, long easy, and long runs with tempo segments is generally a decent mix.
Going back to "fitness level," I was trying to ask how heavy you were (while trying not to come across as too nosy). The more weight (fat or muscle) you carry, the more taxing it is to run, to state the obvious. Elevated HR while running would be less surprising for a heavy build (I see you do lift 3 times a week) rather than for a slighter build.
Let us know if you need help figuring out tempo or fast rep paces. There are online calculators that'll give you a rough idea based on your best times on particular distances (see
here or
there). Also, don't get discouraged! You haven't been running for all that long and 6min/Km is already a respectable pace at that stage in your running life. Also remember that improvements don't happen on a regular schedule, you'll often plateau for a while before suddenly breaking through.