Running Warehouse banner

Trail Running Course

Hydration Test

Since I had some hydration issues last weekend during a two hour run, I figured I better get this under control So, yesterday during my long run (23 miles) I decided to force the fluid/electrolyte consumption and see how the body responded.

My goal was to consume 20oz per hour while running in an easy/aerobic pace. Would the body be able to handle all of that liquid? Would my belly be nothing more that a swirling, sloshing pool of fluid? I had to find out. This will only help my racing abilities especially in the ultra distances where the event could last 5-24+ hours. That is not the time to test your hydration needs.

Conditions for the run:

  • Avg Temperate – 78 F
  • Avg Relative Humidity – 72.5 %
  • Avg Wind Speed – 8.3 mph South

Run Stats:

  • Distance – 23 miles
  • Amount of time running – 3.5 hours
  • Amount of fluid/electrolytes/fuel – 60 oz
  • Fluid breakout (hr:min) – 0 -1:00: 20oz, 1:00-2:15: 20oz, 2:15 – 3:30: 20oz
  • 1 pee break during the run (exciting stuff, this usually never happens)

More pee talk…

Comparing both pre and post workout weight resulted in approximately a 3.6% loss in water weight. I feel this number is better than what it actually shows because I did take one pee break during the run. The scale is a bit of a fudge as well but it is what I got, so it is ballpark.

The biggest thing I noticed is that I actually had to pee AGAIN after I got home from the run (without drinking any water to distort my post run weight measurement). Normally it would take until late afternoon before I would have to go so I know I am definitely moving in the right direction.

I was pleasantly surprised that the stomach didn’t have any problems with the excess fluid but it definitely was mentally hard to force myself to drink that much in an hour. It felt like I was constantly drinking…A LOT! In fact, I was only able to put down the 20oz the first hour. It took 1 hr 15 minutes to empty the bottle for the rest of the run.

Another potential positive is that it seemed like my heart rate did not drift as quickly as it usually does. I finished the run with a heart rate average 10 bpm below the top of my easy/aerobic zone. This is huge and will be interesting to track going forward.

My first experiment with increased fluid consumption was a partial success! I am going to try and stick with the 20oz/hr during my long easy runs for the next month or so to collect a bit more data before deciding to adjust anything.

Happy Training!

About the author

David Hanenburg David Hanenburg is the passionate dirt-lovin' creator of Endurance Buzz and has been playing in the endurance sports world since 2000 after knockin' the dust off of his Trek 950 hardtail thanks to a friend asking to go ride some local dirt. In 2007 he ran his first ultra on the trails and fell in love with the sport and its people. For more information on David's endurance sports journey, check out the About page.

Comments are closed.