Ironman VR6

I signed up for Ironman VR6.  The race is touted as a simulation of their 5150 triathlons.   Those events feature a 1.5km swim, 40km bike, and 10km run.  The VR6 will have two runs (one at 3km and another at 10km) and one ride (40km).

• Short Run.  I'm going to replace an MG interval with the short-run (and treat it as a high-intensity workout).  Clocking in at 1.86 miles, it's longer than my regular short runs.
• Long Run.  This doubles my usual target. 😲 I'm going to try to cap my BPM as usual but increase the amount I cap it at to 150 bpm based on the Karvonen formula (see below).  The 135 cap feels too restrictive for this distance. This corresponds to Zone 5A default in my Training Peaks app. 147 is the max of Zone 4 in this app, so hovering around 145-150 looks okay based on these metrics. 
• Ride.  I've pushed my rides up to 22 miles so an extra 2.85 miles looks like the least increase over my regular activity (and I've gone longer than 40k before). 

This should be interesting.

Target heart rate zones based on the Karvonen formula (with a resting heart rate of 55 based on a month of Apple watch data.)

Target Zone

% Intensity

THR in bpm

Maximum
VO₂ Max Zone

90% - 100%

163 - 175

Hard
Anaerobic Zone

80% - 90%

151 - 163

Moderate
Aerobic Zone

70% - 80%

139 - 151

Light
Fat Burn Zone

60% - 70%

127 - 139

Very Light
Warm Up Zone

50% - 60%

115 - 127