Final tune ups for Clearwater 70.3 and HR deceptions

This week is tough as I am on call 3 of the next 8 days leading into clearwater. This means 14-15 hour shifts and no evening workouts. I guess this forces the rest on me somewhat. Still getting quality tune up workouts leading into race week though.

Tues
6 am: Spin 40 minutes power Z2 with 8 X 30 second power Z3 single leg intervals at 60 rpm.
6 pm: Run 8 in 53:30. Did a 1 mile warm up around 8 minutes. Then 7 mile run alternating 1 min pace zone 4 with 3 minutes pace zone 2. Average pace for the 7 miles 6:03
Very happy with average HR of 128 (low zone 2) with max of 157 (5c)

Wed
5:15 am: Spin 70 minutes. 10 min warm up. Then 5 X 9 min power Zone 4 intervals at 50-60 rpm. 3 min easy spin between each. Everything consistent, same gear, rpm, locked power.
HR for the intervals
1 = 112 ave/ 120 max (HR zone 1)
2 = 118/130 (HR zone 1)
3 = 128/136 (HR zone 2)
4 = 132/140 (HR zone 2)
5 = 130/140 (HR zone 2)

This is exactly how pure HR training on the bike will over-train you if you dont know what you're doing....period.
Maintaining power near 300 watts and all other things consistent, my HR maxed out in high zone 3 and average in zone 1/2
Now...had I purely relied on HR and ignored power? I would have pushed my HR higher than the first 2 intervals, and likely been way too high on the power.

This is evident on some guys I have been biking with, and doing our 45-50 min TT intervals on the same terrain each week. Those using purely HR, drive their HR up in the first 5 minutes of the interval to get into their "zone". These guys are fit and likely are producing way too much power to drive their HR up too early. My ave HR for the last 4 TT intervals has been in zone 2 although my power has been around 310 watts (top of power zone 4). Had I relied purely on HR..I would likely be hitting wattage nearly 350-375 watts to get my HR into "zone 4".

This is exactly why I slowly pull everyone in during the intervals, and by the 30 minute mark I am still going strong and gaining.

My point is this. Pure HR training on the bike is a science, and you have to gain the knowledge to train this way without power. As you get fit, your HR will drop significantly as shown in my last blog. However, with your dropping HR, your power is maintained or even slightly higher. By always relying on the HR...you will likely eventually drift into power numbers that are too high to train with, and eventually this leads to over-training.

This is a primary reason I see so many triathletes get weaker and weaker as the season progresses.

A solution without a power meter? Keep track and write down cadence, ave speed, gear ratio used, and HR on every interval session. Try to duplicate the important interval sessions on the same course. After 6 weeks or so, re-calculate your 20 min threshold and establish new, updated HR parameters. Then honestly adjust your effort to your new HR zones.
Always think about negative splitting each interval, progressing from high zone 1, through zones 2 and 3 as the interval progresses.