My Road to TOWaterfront 42K
This was a fasted, pre-sunrise easy run with my lighting rig.
I haven’t run in the dark in quite a while, so I was a bit nervous about footing – running through pools of light followed immediately by spans of inky shadow. It was a fairly strong run. However, while at an event about an hour after the run, I felt lightheaded and off. Even after a filling brekkie and back at home, I crashed medium-hard into bed. Then the insatiable thirst hit me. After many rounds of electrolytes, water, and soda water, I checked the humidity at the time of my run – 95%! Sneaky b@st@rd! I thought I was getting sick!
📊 Metrics
| Metric | Value |
| Duration | 00:46:48 |
| Distance | 6.66 km |
| Avg Pace | 7:02 /km |
| NGP | 6:54 /km |
| rTSS / hrTSS | 64 / 47 |
| IF (Pace) / IF (HR) | 0.86 / 0.74 |
| Avg HR / Max HR | 142 / 153 bpm |
| Pa:HR | 6.97% |
| EF (from NGP & avg HR) | 1.02 |
| Elevation Gain / Loss | 162 m / 173 m |
| VAM / VAM W·kg⁻¹ | 208 m·h⁻¹ / 1.05 |
| Cadence (avg / max) | 165 / 182 spm |
| Conditions | 13 °C • 95% humidity • Wind 0.4 km/h (E) |
| Time of Day | 05:48 (pre-sunrise) |
EF calculation: ( \text{EF} = \frac{\text{NGP speed} \times 60}{\text{avg HR}} ). Using NGP 6:54/km and avg HR 142 → 1.02.
🔍 What the Numbers Say
- Pa:HR 6.97% → mild aerobic drift in oppressive humidity; still within acceptable range for an easy Z2 aerobic outing.
- IF split 0.86 (pace) vs 0.74 (HR) → mechanical effort outpaced cardiovascular strain, a good sign of durability with humidity capping HR.
- EF 1.02 → in line with recent easy-run trend-economy holding steady despite sticky air.
- Cadence 165 spm → right in your easy sweet spot; footing vigilance didn’t degrade rhythm.
- VAM 208 m/h → rolling work stayed honest without HR spikes.
🎯 Coach’s Corner
Did I Hit the Targets?
- Intent: ~45–60 minutes of steady Z2 Aerobic Endurance.
- Execution: ✔️ Steady Z2 throughout; perceived “post-run crash” reads as under-hydration from 95% humidity, not illness.
Why it worked / What to tweak:
- In humidity >90%, sweat doesn’t evaporate-cooling stalls and fluid loss sneaks up even at easy paces. For future dawn Z2 runs >45 min, pre-load 250–350 ml electrolytes and sip every 10–12 minutes (fasted is fine; “dry” is not).
🧭 Takeaway
I kept it easy, stayed smooth in the dark, and learned (again) that when the air is a sponge, hydrate like it.