Handling Conditions with Respect: Summer Heat & Humidity

The first week or two of running in the heat can be fairly brutal. While for most, “adapting” takes about 10 days, it doesn’t mean that the body isn’t still working hard during high temps and humidity. In the South, we refer to humidity as “poor man’s altitude,” and that is because physiologically humidity and altitude involve similar processes of adaptation. While exercising in the heat, your body is actively taking oxygen from your working muscles to cool you down through sweating. When at altitude, you simply start with less oxygen to begin with. Working out in very hot conditions provides us with a number of challenges when it comes to adaptation and performance. One's ease of adaptation depends on a number of different factors such as one's acclimatization state, hydration and overall aerobic fitness. Different sweat rates can also play a role in performance. 

So why is working out in the heat so hard? 

1) As we already mentioned, the process of external cooling requires actively taking oxygen from working muscles

2) Heat stress reduces one's ability to have maximal metabolic rates during aerobic exercise 

3) The average person loses about 1 liter of sweat per hour during exercise in hot conditions. That can be hard to efficiently replenish while running. 

4) Continuing from point 3, dehydration from sweat loss decreases blood volume which results in being less efficient at cooling and causing elevated core temperatures 

5) Metabolic demands compete with thermoregulatory demands, making it challenging to maintain proper cardiac output 

So what do you do about it?
It is important to have adequate respect for the conditions you run in, for the purpose of performance and safety. In heat, it can be easy to "hit the wall" and suffer for extended periods if we don't take into account the environment we are running in. Recovery days need to be taken extra seriously in hot conditions, check out our blog on recovery runs if you need further explanation.  In our article Beat the Heat we have some tips for hot weather running. 
The summer is a great time to get fit if you are smart about it. Be aware of the challenges and take advantage of some summer running tips. We hope this helps you tackle your summer running! 


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My coach, Brandon, has really motivated me to get into shape.  He gave me a simple walking plan and eventually I was jogging!  I was able to work into my busy schedule....and with two kids and working full-time, that is a hard thing to do.  Over time I’ve been able to go longer distances and I am looking forward to doing my first 5K this spring.  Thank You RunningLane!!!!