The Runner's High

It all started the first week of September, in reaction to being relegated indoors after a summer of being active outdoors, teaching kids how to bike. I plotted a 7-km route from my door to the office on MapMyRun.com and ran it one sunny autumn morning.

I wore my heart rate monitor and I recall my heart rate average being somewhere around 171 for the 43 minutes it took me to navigate up and down over the river valley and past the morning rush of streetcars. The run burned around 300 kcal too, if I recall.

I didn't plan ahead so ended up wearing my sweaty running kit all day. Luckily, my office is the Transportation Planning Bicycle Safety division so sweaty apparel is normal, although even there I was pushing the definition of "normalcy." Come 5pm, I ran home, covering the distance more quickly - 40 minutes.

Two days later, I was ready to go again and this time came prepared with my iPod, water bottle and debit card strapped to my hip, and a change of clothes waiting for me at work.

I took this 'alternative mode of transportation' twice a week until two weeks later, I discovered the office has a shower room and to my delight, it mimics a rain forest in volume and warmth. I just need the caw of a parrot and a pina colada waiting for me afterwards. These 10-minute showers have become a luxurious addition to my workday since.

It's a thrill to track my progress on my heart rate monitor. I'm now down to 34 minutes, up to 35 km a week and burning between 400 and 500 kcal each run. I'm also down to 130lbs, which I haven't seen since grade 12!

The most telling indicator of my muscles acute adaptiveness is that my heart rate average has decreased to around 160 - 165 beats per minute while my speed has increased. My cardiac output, the amount of blood pumped to my working muscles per minute, is determined by the amount of blood ejected from the heart with each beat (Stoke Volume) multiplied by the number of beats per minute (Hear Rate). My heart rate has decreased, but by means of the Frank-Starling mechanism, the walls of my heart have stretched, allowing more blood to be ejected with each pump. Less beats but more blood getting to my muscles, and more oxygen being absorbed means I'm running more efficiently.

I've also started to take a 10-km route twice a week, as the lure and rush of endorphin from running is addictive. My work is flexible, so if I show up at 9:15am, after an hour of running, I'm still able to have my shower, my 500mL of chocolate milk (a fabulous recovery drink) before settling down to work for a 9:30am – 5:30pm workday.

It was today I realised that this is truly not a common thing to do. It was cold, zero degrees and lightly raining, but I dressed warmly with a light-weight long-sleeve Marino wool base-layer, a wind-proof toque and light running gloves. But today I only saw two other runners in my 53-minute 10km run, when often it's a dozen or so sharing the route.

Tonight, running home in the dusk, it was just me and my reflective light pounding the sidewalk. Hed Candy blasting smooth tunes through my earphones, the heat radiating off my shirt gently smelling of clean laundry, the rain refreshing on my cheeks, my arms and legs pumping in time, all parts rhythmically aligned. I had hit my stride: a meditative weightless state.

Up a steep incline, I remind myself to decrease the amount of time each foot contacts with the ground. Faster feet, higher knees, arms pump, elbows up and behind. A slight burn of lactic acid in my thighs; heart rate spiking to 182, but still much lower than the 191 when I first took this hill in September. No rest at the top, push it, split-time style - 12 minutes until I'm home.

I will take the weekend to recover, but come Monday, I'll be back on that hill, getting another dose of the runner's high.