Don't Sweat The Small Stuff

​Do you participate in endurance activities?  If so, do you know what your sweat rate is?  If not, you may want to find out, because you may be compromising your performance potential.
 
During exercise, humans sweat.  Some of us sweat a lot!  That loss of water can impact your sports performance.  Your body needs water to perform many of its essential functions, including keeping your muscles operating properly.  If you lose too much water, things don’t work as well.  At the extreme, they don’t work at all and your body starts to have lots of problems.
 
So how do we know how much we should be drinking during exercise to prevent us from losing too much water?  Well, there are two schools of thought.  One suggests that you should drink when you are thirsty.  This works well for some, but not all, people.  The risk here is not recognizing thirst early enough to prevent dehydration, and thus performance loss ensues.  The second school of thought is to drink on schedule, regardless of whether you feel thirsty or not.  The risk here is drinking too much for the particular conditions, leading to some unpleasant and potentially dangerous consequences.
 
Is there a compromise between these two schools of thought?  YES, and that is where accumulating data comes in.  When I work with endurance athletes, I encourage them to keep a journal that includes the environmental conditions in which they are training and their sweat rate for the day.  This allows them to have a good sense as to how much water their bodies need under particular conditions.  On race day, they assess the conditions, check their journal, and get a good sense of what their fluid needs are likely to be.  Keeping that estimation in mind, they can avoid drinking too much and still respond to thirst cues as needed.
 
How do you calculate your sweat rate?  There are a number of examples of how to do it out there.  Here are a few of my favorites:
 
https://ksi.uconn.edu/wp-content/uploads/sites/1222/2015/04/Sweat-Rate-Calculator.pdf
 
https://www.cdc.gov/nceh/hsb/extreme/Heat_Illness/Sweat%20Rate%20Calculation.pdf
 
If, like me, you are mathematically challenged at times, here’s a handy online calculator:
 
http://www.triharder.com/thm_swrate.aspx
 
The moral of the story? Planning ahead means you won’t need to sweat the small (or not so small) stuff regarding hydration on race day!