The number 15.

Last Thursday I decided to take my borrowed bike out for my maiden voyage. It was 2 p.m. and 112 degrees. I wasn't worried about the heat because I live here, in the desert, year round. I figure I'm accustomed to the heat. My training schedule for last week called for one ride, 5-8 miles. I decided to do 6 miles. Four different times during the ride I had to get off the bike and seek shade, I was dizzy, panting, and would have cried had I thought someone was around to rescue me. It took me an hour to finish the 6 miles.

Today I headed out on the same 6 mile ride at 10 a.m. and only 97 degrees. It took me only 35 minutes to complete the exact same ride, stopping once at midpoint to get off the pedals and drink some water. Today I learned the value of 15 degrees.