Training // Heat Acclimation

I have had some memorable experiences with heat exhaustion.  There was the time when I pushed a rescue litter up the Mt. Wilson trail to a patient with heat exhaustion only to succumb to myself.  Another time I had to bail out of a 26 mile Angeles Crest 100 training run 10 miles from the finish and call for someone to pick me up, not just ending my run but also my partner’s as I was his ride.  The worst and most frustrating experience was at mile 20 of the 2017 Mt. Disappointment 50km, where I knew I was in the early stages and had to sit for 40 minutes while runners just kept rolling by.

I had come to expect that at least once a year I would get zapped by the heat.  It seemed to me it was just part of being an ultrarunner in Southern California.  I had a lot of knowledge through my search and rescue days about the mechanisms and treatment of heat injury, but never any clue about how to really prepare to operate in the heat.

I had signed up for the 2018 Angeles National Forest Trail Race 60km (previously called Mt. Disappointment) and I was determined to not relive the previous year’s race.  I had seen runners I follow on Strava mention they spent an hour in the sauna after a training. My training partner had prepared for Marathon des Sables by running in a touque and down parka.  I had pieces to the puzzle but I didn’t know how to work it into the training.  Three weeks before ANFTR and I was starting to panic and then I came across this  article on heat acclimation.

It was a huge relief to finally have something that could be turned into plan.  I decided that I would do a 10 day hybrid approach (active and passive) to acclimation.  I put a goal each day in my training plan to keep me accountable and went to work.

What follows is a diary of the process:

Day 1 – Ran for an hour including a 20 minute uphill tempo. Average temperature was 92F. Things went as expected for the first day and I ran slower than my best even though I had a recovery week just prior.

Day 2 – Easy 30 minute run up and down the wash with temperature around 90F. I followed this up with 30 minute soak in 104F bathtub.

Day 3 – Got my long run in for the week in the Crystal Lake area.  Took the Islip Wawona Trail to Islip summit then jumped on the PCT to Hawkins Ridge Trail and looped that back on the Hawkins Fire Road/Lost Ridge Trail ~16.6 mi 4018ft 3h 10m avg. temp. 87F. After lunch I did a 30 minute soak.

Day 4 – Rest day as I had gone a little over with the training stress day before.  Did yard work and then a 30 minute tub.

Day 5 – Easy flat 4 mile run ~30min average temp 89F followed by another 30 minute hot tub.

Day 6 – Six ~2 minute hill repeats in 90F temperature followed by 30 minute soak.  Interestingly I did not notice any stinging when sweat dripped into my eyes, seems that my electrolyte retention is changing.

Day 7 – Easy paced 10km with temperatures around 88F again I followed with a 30 minute hot bath

Day 8 – Uphill 20 minute tempo for a total of 10km a little cooler than yesterday but still hit 90F. Sticking to the 30 minute bath after to continue the “burn”. Perceived effort was about right on with the pace I was holding as opposed to last week where I felt loopy during the workout.

Day 9 – Yoga and stretching followed by a 30 minute tub

Day 10 – 10 mile long run on the Silver Moccasin trail as a course preview.  This took a while to drive out to but after I had lunch I did another soak because the outdoor temperature wasn’t as hot as I liked.