Aerobic Endurance in Summer Heat – July 27, 2025

Build Phase 1 / Week 3 / Run 5 – Road to TOWaterfront 42K

Setting the Scene

Another Sunday, another heat warning. An hour before heading out, I downed a Maurten Solid 160, then began sipping Nuun in preparation for what I knew would be a sweatfest. I brought a full 500ml bottle with me on the run and tossed in a few SaltStick Fastchews for good measure, two before launch, then every 2K or so.

A comic book-style illustration of a muscular, bald African-Canadian man running on a wooden bridge in Parry Sound. He is wearing a black tank top, black shorts, blue running shoes, and Shokz OpenMove bone-conduction headphones. His face and body glisten with sweat under a partly cloudy summer sky. The bridge is lined with colorful murals of trees and figures, and lush green trees frame the background.

After 5 minutes of dynamic mobility drills, I hit the road.

My plan? Run conservatively. My reality? Let’s just say it’s a work in progress. I knew from the get-go that my heart rate would creep: full sun, high humidity, even the occasional nose scratch would spike it.

But on days like this, I defer to HR and RPE over pace, always.

🎧 Binaural tones through my Shokz kept me dialed in, steady in stride and in mind.

📊 Workout Details

Metric	Value
Duration	40:08
Distance	5.63 km
Avg Pace	7:08/km
rTSS	50
hrTSS	40
IF (Pace)	0.83
IF (HR)	0.74
Avg HR	146 bpm
Max HR	156 bpm
Pa:HR	8.02%
Elevation Gain	148 m
Elevation Loss	163 m
Avg Cadence	162 spm
Calories Burned	342 kcal
RPE	4 – Somewhat Hard
Weather	23°C, feels like 24°C, 95% humidity, WSW wind at 4.5 km/h

🧠 Coach’s Corner

This was a solid aerobic effort in tough conditions. A few standout points:

IF (Pace 0.83) vs IF (HR 0.74) confirms smart pacingyour internal load stayed in check despite heat.
Pa:HR at 8.02% shows a slight cardiac drift, which is expected given the humidity and elevation.
EF at 1.00 signals efficient aerobic output relative to heart rate, even in suboptimal weather.
Elevation Gain of 148m adds contextthis wasn’t a flat cruise.

You executed well by leaning on heart rate and perceived effort over pace metrics. That’s veteran decision-making.

🔗 Related Reads

💬 Final Thoughts

Some days, the real workout is staying smart. I didn’t chase the pace, I monitored the drift, and I kept my effort true.

Heat, humility, and hydration. This one had it all.