Lighter is Faster but Hotter is Slower

This week was a mix of happy news and frustrating days. Here’s the two sides:

Lighter is Faster

It’s just a fact. Hold a 10 pound bag of flour and run a mile. Now, run a mile without the bag. Faster? Obviously. Same applies to body weight. The conventional wisdom is that a pound of body weight lost equals about a 2 second per mile gain in running pace. This assumes that there isn’t excessive, unhealthy weight loss or loss of lean muscle mass.

In addition to all the running in my marathon training, four weeks ago I added in a 1 hour strength training session 3 times a week with a personal trainer at my gym. Coming back from a baby to do my first marathon in just 8 months is no small matter, and I thought the added muscle strength would be such a big help!

I begged the trainer to do a body fat check on me Saturday so I could see if there was any progress. I kinda felt like I looked a little better but wasn’t seeing any huge changes and my clothes didn’t really fit differently.

So trainer Jeff pulls out the calipers and measures in 7 different places. He crunches the numbers… 4 weeks before I was at 30.9% body fat. Now? 25.8% body fat! In 4 weeks of really hard work, I had lost 5% body fat. I had also lost 8 pounds overall, which breaks down to about 12 pounds of fat lost and a 4 pound gain in blood volume and lean muscle!

Hotter is Slower

In North Texas we’ve now had about a week of high temperatures above 100 degrees. Yes, we know it gets hot in Texas. But weathermen have reported this is about 2 weeks earlier than we usually start hitting those temperatures.

Normally, looking at my training schedule within a vacuum of no other variables, I would have loved to have gone for 18-22 miles for my long run this weekend. However, it’s just become so hot and humid that the draining effects of a 4-5 hour long run (thanks to my slower pace) have to be balanced against the potential benefits of a run of that length. With 2 20-milers done, the urgency in another very long run in those conditions is waning.

So Saturday, a group of us headed out at 5:30 am. And by 8:30 am, we were done with 13.5 miles, and it was already 80 degrees and 80% humidity. A later 1.4 miles on the treadmill brought the day to just about 15 miles.

And the pace for these long runs is getting a little slower. I feel a little stronger on my midweek runs after all the running and strength training, and I certainly hope I’m getting faster with the weight loss as well. However, I can’t test that out when temperatures are so blazingly hot. It makes it very frustrating. I’m thinking this may translate into some faster times in the fall, but for now… I just want to stamp my feet some days.

Next week: Just keep trucking along. I’m just maintaining fitness and running base at this point. And unfortunately, appointments mean getting in some of my usual run days will be difficult.

Libby Jones has been running for 5 years, is a self-described “serial half-marathoner”, but has never attempted the marathon distance. She is also an active part of the Dallas-Fort Worth running community. She is the Founder and Race Director of the New Year’s Day Half Marathon in Allen, Texas; the Executive Race Director for Heels and Hills, a non-profit geared towards getting women fit and active; the North Texas State Representative for the Road Runners Club of America; past Dallas Running Club President & 2008 RRCA Scott Hamilton National Outstanding Club President Award Winner; and an RRCA-certified running coach. She’s also a wife to Steve and a mother to Marissa (3 yrs) and Sophie (3 1/2 months). Read her blog “The Active Joe” and follow her on Twitter @libbyruns