Positive Running

I only run every other day, with occasional exceptions.  I use different cardio machines on days when I don't run, and I record the calories I burned.  Today, I burned 362 calories in 30 minutes on the stationary bike and 400 calories in 30 minutes on the elliptical machine. 

A running buddy has asked for an explanation of dew point.  Dew point is an important factor when planning runs, especially on hot summer Arkansas mornings.  Dew point is the temperature at which water vapor (gaseous state of water) condenses into water liquid on a solid surface.  The same dew point can be viewed in the opposite direction -- evaporation of water from a liquid state to a gas state, which occurs at the same temperature as the dew point.  The higher the dew point, the hotter our sweat has to get before it will evaporate, that is, transform from liquid to gas.  Evaporation of sweat is one way our bodies keep cool when we run.  Hence, if the dew point is high and the temperature is high, our sweat has to be hotter before it will evaporate and cool us down.  So we risk the potential of overheating due to our bodies trying to cool down internally when the dew point is high, unless we drink cool fluids and/or slow down when we run. 

If anyone has a better explanation of how dew point affects runners, I would be interested in your comments. Thanks.