During the long cold winter in Northern Virginia I eagerly yearned for spring and summer to arrive.

This week I wondered why I was looking forward to the warmer weather. Spring seems to come and go in two weeks in the DC area. Just when it warms up a tad, WHAM, the heat and humidity come on strong, making me wish for the cooler temperatures of fall long before the summer has even really began.

Thursday I started my run a tad after 8am and at that point it was already 84 degrees. Just for giggles I looked up the humidity and temperature for DC at the time I was out running.

Temperature: 81 degrees
Humidity: 67%

When I started the run I knew there was no way I would make it through any more than 4 miles if I attempted to run at my typical pace. I allowed myself to adjust and though it felt just as hard as a faster pace would have, it was a bit slower. Slowing down helped me push through 6 miles again. Baby C slept the whole time and Miles was bribed into being happy by the promise of heading to a lake after to feed the ducks.

I wondered how much the humidity was affecting my performance. I was sweating more than I normally do, yet did not seem any cooler. My skin was soaked as if none of the sweat was evaporating.

According to wikipedia this is what happens to your body during times of high humidity.

‘The human body sheds heat by a combination of evaporation of perspiration, heat convection in the surrounding air, and thermal radiation. Under conditions of high humidity, the evaporation of sweat from the skin decreases, and the body’s efforts to maintain an acceptable body temperature may be significantly impaired. Also, if the atmosphere is as warm as or warmer than the skin during times of high humidity, blood brought to the body surface cannot shed heat by conduction to the air, and a condition called hyperpyrexia results. With so much blood going to the external surface of the body, relatively less goes to the active muscles, the brain, and other internal organs. Physical strength declines, and fatigue occurs sooner than it would otherwise. Alertness and mental capacity also may be affected, resulting in heat stroke or hyperthermia.’

With this knowledge in mind I do not feel bad about slowing down one bit. I make it a habit to run a lot of my runs on perceived exertion. Running this way means at times my pace will be slower than my optimal training pace, or a tad faster if the weather is nice and I am feeling the good.

This week I have only run on feel. The runs were hard. Some of them felt harder than marathons I have run.

That which does not kill me, makes me stronger – right?! These runs prepare me for hard races.

Do you live in the DC area? Have you been running or working out in this terrible heat and humidity?

Have you commented on my Hood To Coast post yet? I REALLY REALLY REALLY want to get picked for the nuun all women all bloggers team and need YOUR help!


  1. Jackie Smith (the other one) says:

    I'm so glad the heat hasn't hit yet in central CA. We're lucky this year! When it gets really nasty, I run inside.

  2. Courtney @ I CAN DO THIS says:

    You bring up a good point. We're quick to be hard on ourselves for not being able to perform as well when the humidity and heat hits. I ran in 82' and 81% humidity yesterday, and I blamed the increased effort on running a marathon last Sunday. But it seems like at the start of every summer, it takes a couple of weeks to acclimate to the weather changes.
    I really like your idea of running on perceived exertion. I want to give it a try!

  3. I live in Central Florida and we have hot weather plus high humidity for many months in year. This is the time of year here where a lot of runs need to be done indoors or before the sun comes up.

  4. carlybananas says:

    This part is good to know: "Under conditions of high humidity, the evaporation of sweat from the skin decreases" – because I've been adjusting my effort/pace but still finishing up DRENCHED in sweat. I feel a little less disgusting now. :)

  5. I live in Southern Ontario and we went from spring to full out summer last week and the humidity was crazy. Now we are experiencing cooler days, but oneday next week it is suppose to get hotter!!
    But it is true, in the winter we long for summer and in the summer we long for cooler days.

  6. Very interesting. I have been running in this DC heat/humidity. I usually run during my lunch break M-F and as you can imagine, it's intense! I more or less quite paying attention to pace and just try to get through the distance.

  7. Elizabeth says:

    I just pace myself using a HR monitor. My pace is slower, but the heart rate is nealy the same as cooler weather, so I know I am not overdoing it. Thanks for the info, it's very validating for the need to slow down.

  8. It is always humid in Texas so I run before the sun comes up. An 8am start time would be way too late for me. It was interesting to learn about the effects of humidity on sweat. I hope it cools soon for you!

  9. Tina @GottaRunNow says:

    I'm running in the humidity, too, here in Houston. I've had to lower my expectations about my pace lately and I'm already looking forward to cooler weather in, oh, 4-5 months!

  10. Thank you for the info – I find this very helpful as it is ALWAYS humid here in Columbus, Ohio! I ran a 5K yesterday and even though it was cooler – the humidity was horrible and I had to slow down A LOT. I was disappointed in my times, but your post makes me feel better about the race, given the conditions I was running in. I need to remember to "run by feel" more often (especially when it is hot and humid) and not worry about my time so much! Thank you so much. :)

  11. It's been in the high 90's and humid in Charlotte for a month now :( I cannot remember why I whined all winter either!

    I am always so much slower in the summer and do all of my tempo and speedwork on the treadmill. It's the only way I can not get discouraged!

  12. Allison says:

    I feel like every summer I have a harder time with this weather. I know I just need to go through an adjustment period, but that doesn't make it any easier! I just try to go out as early in the morning as possible and hope for the best.

  13. This heat is BS. I am temporarily protesting running and hoping that I either acclimate or the weather turns a bit. What happened to spring??

  14. Jennifer says:

    I live in Charleston, SC and it's been super hot and humid here too, but then again that's just how it is here in the summer so I understand!

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