By week two, it dawns on me that I’m far more self-conscious in the gym. When I’m running outside, the only time I modify my behavior is to smile at another runner. In the gym, even though I thought I didn’t care what anyone else thinks, I dial up the speed so even my easy runs are fast for me. I know that’s a recipe for injury, so over the next couple of days, I try my hardest to block everyone around me out.

Halfway into my training block, I put my finger on the biggest difference between training indoors and outdoors: I don’t feel fatigued after running. I don’t have any of that bow-legged stiffness that comes with completing a tough run outside. And while I try to block out thoughts that perhaps I’m not working hard enough, it’s a fact that this is the easiest training block I’ve ever done. At my normal pace indoors, 10km is cruisy-comfy, and the extreme sweating is due to the lack of AC rather than my effort level. I reluctantly decide to add 1% of incline to all future runs.

The final 18km long run (at 1% incline) two weeks out from my half marathon hurts. I take two gels to the gym, which makes me feel like a poser. I even take my carbon-plated race shoes with me, hoping to make the long run go faster, choosing a treadmill in the corner of the gym facing a wall. This is a mistake because other than my pounding music and dehydration headache, there’s nothing to distract me. I run for what feels like hours… before glancing at my watch and realising that only two minutes have passed. I take a gel. I really need a wee. Almost 5km down. Stars are reborn and universes collide in the time it takes me to reach 6km. I brazenly put my speed up to something fast and unpredictable to make the time pass.

“I trained for a half marathon by running only on a treadmill, and I was shocked at my times – these are all the benefits of jogging indoors”