Although it may not be officially summer yet, the last week in May has certainly felt like it with hot humid weather. The timing couldn't be better, as Coach Terry has written this edition of Coaches Corner and he's wisely chosen hydration as his topic. Thanks again to Terry for writing this.....be sure to read it below!
Thanks again to everyone who helped out at the Noelle's Gift of Fitness 5k Run; this is a great cause and your support is appreciated. We'd also like to congratulate Lynn and Sig for their great runs in the Alvinston to Watford Road Race, Mike for gutting it out in a brutally hot 10k at the MEC 10k in London and last but certinaly not least, Coach Scott for completing his first 80k race at the Indiana Trail 50/100 under really awful weather conditions. Way to go Renegades!
In the months of May / early June we welcomed two new Renegades to the group: Yvette Glover and Lonna Seed. Most of you know these ladies but if not, please introduce yourselves at an upcoming run. Welcome ladies!
Although some people's plans are up in the air, several Renegades will be running the Bridge Run and/or Boys Home Run in June, Lynn will be competing in an ultra-marathon in Niagara Falls, Patricia has plans for another race in Edmonton in June and Terry will be competing in the Ironman 70.3 at Mont Tremblant. Go Renegades!
Now.....here's Terry's column on hydration.....we know you'll enjoy it!
Hydration and Measuring your Sweat Loss Rate
I was tempted to title this article ‘get naked’, but more on that later. As we saw on Facebook, there was consideration given to cancelling the Ottawa marathon this past weekend. The Medical Director for Run Ottawa had the following tips for running in the heat:
- Dress appropriately (i.e. wear clothing that is lightweight and light in colour.)
- Increase your fluid intake
- When passing a water station, take one cup of water to drink and another to pour over your head to cool down
- If you have family and friends along the course watching, get them to bring ice cold water/sports drinks that you can pour over yourself or drink
It is useful and pretty interesting to measure your sweat loss rate – you can’t change what you don’t measure. Knowing your sweat loss rate may be particularly important when you’re running or preparing for a ½ marathon or marathon in hot weather. The sweat loss rate calculation (below) will be more accurate the longer your run: aim for 1 hour minimum. And do the run on a warm/hot day. Bear (bare) with me on the details.
You need a digital scale (accurate to 0.1 kg) for body mass measurements (weight). You weigh yourself before and after a workout/run and keep track of how much you drink. When you weigh yourself, make sure you are completely dry and either nude or wearing the same dry clothes for both pre-run and post-run body mass. If you wish to drink during your run, take a bottle with you and allow for any not drunk. For this test, you’re not allowed to pour any water from your bottle over your head/body. For simplicity of this calculation, you are not allowed to pee during the workout and only after you weigh yourself post-run. Guys – you can do this! (we know it’ll be no problem for the girls).
Sweat loss rate = body mass before – body mass after + [fluids drank in ml / 1000] / time in hours
Pretty easy, right? I can help you if you’re mathematically challenged – or just ask your 8 year old to do the calculation on your cell phone. You need to do the test several times and note the weather conditions and how you felt during your run (RPE on a scale of 1-10).
Knowing your sweat loss rate is only a start, but it may help you to zero in on how much fluid intake is right for you for a long run or for a ½ marathon or marathon. I make use of my sweat loss rate to get the right amount of fluids during the 180 km bike portion of an Ironman. In most cases you don’t want to replace all of your fluid loss for optimal performance: 1-2% is fine and maybe more. But you don’t want to have a net gain in fluids for optimal performance: and the slower your pace the more important it is to not drink too much.
This leads to the next step in the hydration analysis: measuring the sodium concentration of your sweat so that you can maintain your blood sodium level to prevent hyponatremia. This is a significant issue for an Ironman athlete, but I won’t deal with this subject in this article.
For more information see: Why the Big Fuss Over Hydration, By Dr. Jon Hooper, Medical Director, Tamarack Ottawa Race Weekend