Humidity Rears Its Ugly Head

I have begun the last two days around 5:30 in the morning. I have eaten breakfast and mustered enough motivation to be out the door by 6:00 am.   Each day I ran about 10 kilometers or about 6.2 miles.   The reason I am running this early is to avoid the 90-100 degree temperatures which exist for the remainder of the day.

For each run, the temperature was about 73 degrees.  The marked difference between yesterday's run and today's run was the humidity level.  They were much higher today. At the four mile mark on today's run I was overcome by a sense of light-headedness combined with a precipitously decline in my energy level.   I was nearly reduced to walking the last two miles, but I was able to finish the run at a much slower pace to facilitate self-preservation.

My next two races are a one mile run in two weeks and a six mile run in four weeks.  I am not worried about altering my race preparation for the mile run, but I may have to scale back my performance expectations with regard to the six mile race in early August.

The August 10K  race is scheduled to begin at 8:00 am.  The factor most critical to whether I attempt to achieve a new personal 10K record will be the humidity level or dew point.  I have found if the dew point (temperature) exceeds 65, then running becomes extremely laborious because of difficulties I encounter with breathing.  I will shift my focus to enjoying the run at a relatively leisurely pace if the weather conditions are not conducive for a fast outing.


excerpted from http://www.weatherquestions.com/What_is_dewpoint_temperature.htm.

The dewpoint temperature is the temperature at which the air can no longer hold all of its water vapor, and some of the water vapor must condense into liquid water. At 100% relative humidity, the dewpoint temperature and real temperature are the same, and clouds or fog can begin to form. While relative humidity is a relative measure of how humid it is, the dewpoint temperature is an absolute measure of how much water vapor is in the air (how humid it is). In very warm, humid conditions, the dewpoint temperature can reach 75 to 77 degrees F, but rarely exceeds 80 degrees.

Interesting facts:

SOUPY AIR: When the dewpoint approaches 75 degrees F, most people can "feel" the thickness of the air as they breathe, since the water vapor content is so high (about 20 grams of water vapor per kilogram of dry air, or 2% of the air's mass).