cymru66

With 2 out of the 3 Key Run Workouts completed this week, I thought I’d take a few minutes to reflect on my achievements so far. I must admit my initial reaction after both workouts (#1 and #2) was one of disappointment and frustration. I feared 2 weeks away from the heat and humidity of Virginia Beach had left me unprepared for a summer of racing and tough 4 month marathon training plan leading up to the Marine Corps Marathon in October. However after reading the Run Less, Run Faster book to prepare for tomorrow’s long run, I stumbled across some interesting facts:

• Not surprisingly, ideal conditions for running performance are between 45°F and 60°F.
• Anything above or below this will have adverse on running times.
• Heat is the most dangerous and difficult environmental condition to combat.

When temperatures rise over 60°F, you can expect a 1 to 2% loss in running efficiency for every 1.5°F increase in temperature. This decrement is naturally more pronounced as the distance increases. As an example, my last 2 track workouts were performed in temperatures approaching 90°F. According to the above, this would impact my running efficiency by a massive 20 to 40%! No wonder my times were not what I was hoping for! I’d paid particular attention to my hydration on both days and was confident this wasn’t a factor in my perceived poor performance, but didn’t realise the heat would have such a negative influence. Actually in previous years I’ve thrived in the hotter summer conditions.

The book also covers the topics of hydration and sweating. It explains the body adapts to the heat through increased bloodflow to the skin, increased sweating and a higher core temperature. Any sweat lost needs to be replaced through correct and regular hydration and surprisingly (to me anyway), it’s only water that evaporates from the skin which results in significant cooling. Sweat running off your body reduces body heat very little. Furthermore, high humidity reduces the rate of evaporation as wet skin doesn’t sweat as much as dry skin. Therefore it’s important to take in fluids rather than pour them over your head - something else I’m guilty of doing.

Heat acclimatization requires exercising in the heat. It’s no use just being exposed to the heat, even for extended periods of time, in the hope you’ll adapt to the heat. The human body learns to sweat more effectively and tolerate liquid replacement as you train in hotter conditions. It takes a full 10 to 14 days to fully acclimatize to a hotter environment, although early adaptation can take place within 5 days.

So, if the heat is such a major factor which effects performance, how am I to train at the level the plan suggests? The book suggests either running early in the morning when there’s little radiant heat or simply accepting your times will be slower depending on the temperature and humidity. I guess you could also train based on effort if you wear and use a heart rate monitor.

At least I’m not as concerned as I was a couple of days ago about the first 2 workouts, and I’m looking forward to the first “long run” of the program tomorrow morning - 13 miles at Planned Marathon Pace (PMP) plus 30 seconds per mile, which for me means right about 7:11 pace. I’m allowed to use the first couple of miles as a warm up, but I envisage at least 10 miles at PMP before the last mile cool down. Temperatures will be in the mid 70s until about 8am, after which they’ll hit 80°F - I’ll need to get out early if I’m to get the most out of my workout. Of course I’ll post the usual statistics over at my Run Bulldog Run blog sometime tomorrow after I’ve had my traditional summer ice bath and midday nap…

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This entry was posted on Saturday, July 14th, 2007 at 8:58 pm and is filed under Running. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.