Why is it so difficult to run in humidity?

Question

I am an avid runner, about 4-5 miles a day, longer on the weekends. I am in the Long Island NY area and the humidity has been brutal. From a medicinal perspective, what is it about humidity that just obliterates my run? You cannot get a good solid breath of air, and it saps your energy. Is it the water content in the air, I have always suffered this but have not gotten the real explanation of why it is so hard to run in humid conditions. Thanks

Answer 1

Humans are extremely efficient runners.  One of the reasons is our ability to shed heat.  It is one of reasons runners who run with their dogs must be careful - dogs will overheat more quickly than humans.

However, very humid conditions interfere with our ability to shed that heat. In dryer conditions as we sweat the evaporation of the sweat cools us.  In humid conditions evaporation is slowed causing our bodies to overheat.

Answer 2

I believe a reason is you get dehydrated faster. Dehydration degrades ability to run fast  

Answer 3

The rate of evaporation is inversely related to relative humidity (the actual amount of moisture in the air to the greatest amount it can hold at a given temperature). The higher the humidity, the lower the rate of evaporation due to a reduced diffusion rate for water leaving the surface of the body.

It is difficult to run because the humid conditions effect  our body's effort to maintain an acceptable temperature.

Sweat's principal function is to help regulate your body's temperature, by providing a cooling mechanism through our skin.    As u run and your body heats up inside, more blood goes to the skin where it helps to cool u  by sweating... sweat  evaporates from  your skins surface  and heat is lost and your body temperature is able to be  maintained. but HUMIDITY prevents sweat from evaporating from your skin, therefore it does not cool you off and your body  overheats.. your expending more energy than your body's use to thus making your run BRUTAL!  

My advice to you is to try to run when the humidity is the lowest, early morning  and  evening.

Answer 4

humidity traps heat in the air like a blanket so your body spends energy trying to keep the body cool that it would otherwise use for running. This results in five to even thirty seconds off your mile pace.

Answer 5

because the air is already moisture laden, you sweat doesn't evaporate as it normally should therefore you body can't cool itself off as well as if it were dry and the body's performance suffers.