It’s the time of year when it’s still dark when I leave my house for the day. On one particular morning this week, I put on my jacket and gathered my things with more reluctance than usual. I was tired, trying to ignore a headache that was becoming more and more insistent, and I felt very much like curling up and going back to sleep.

But as I stepped out into the crisp, quiet morning, I couldn’t help but think that breathing in this early freshness might just be worth the struggle to get out the...