Hydration for Sweltering Summer Rides

By Troy Jacobsen | July 21, 2009, 12 a.m. (ET)
I wanted to share a quick personal story with you regarding hydration and the importance of staying properly hydrated for maximum performance.

First of all, living in Tucson now during the summer, I fully understand why many native Tucsonians leave Tucson in July. We've been saddled with day after day of 100+ degree (F) temperatures under the blazing hot summer sun. And because we're also in the midst of monsoon season (storms roll in after 4 p.m. like clockwork), the relative humidity is a bit higher too. Mind you, I'm not complaining... after all, from October through March we have almost perfect weather for outdoor activities with temps in the 70's and 80's!

Saturday, I went out on a 45 mile bike ride in the late morning and the temps were hovering around 105 degrees. It was brutally hot with the sun baking the desert. I took with me two 24 oz. water bottles of plain water, thinking that since it would be an aerobic zone 2 workout (low intensity), I'd be ok and wouldn't need more fluid.  Wrong! I got back home and was dizzy, felt like horse crap and drank huge quantities of water for the rest of the night. I think I fully hydrated just before hitting the sack.

Sunday morning, thinking I'd learned my lesson, I decided to go out on another ride (inspired by watching the TDF, of course) around the same time in the 105 degree heat. This time though, I took two 24 oz. water bottles PLUS a 70 fl oz. Camelbak with me. I mapped out a 42-mile ride from my home town of Oro Valley to a small town called Rillito. Another Z2 ride for me (sometimes Z3), I weighed myself before heading out and tipped the scale at 170 pounds. 

As soon as the ride started, the heat was searing and the sun felt like it was swallowing the earth. Ever opened a hot oven to feel the heat rush out and hit you in the face? I was averaging about 20 mph and my powermeter was hovering at a very comfortable 200-220 watts on average, with a cadence in the mid 80's. I started drinking from the Camelbak immediately to combat the severe dehydration I'd experienced the day before. The ice cold water was a treat and the cold Camelback on my back helped cool my core temperature for a while.

At the turnaround in Rillito, about 20 miles into the ride, I'd already gone through the 70 oz Camelbak and was starting to hit my water bottles. I was amazed at how thirsty I was and how fast I was plowing through my fluids! I felt good though... with an average speed still just over 20 mph and my average power over 200 watts...it was almost effortless. By the end of the ride, I'd finished my two 24 oz water bottles and the 70 oz Camelbak – 118 ounces of fluid (about 7.3 pounds of fluid).  I was not dizzy, only moderately fatigued and could have gone for a nice run (if I was yearning for a bout of heat stroke, that is.)

The ride finished and my results were as follows. They included (including stops, etc.):
Average Power: 204 watts
Elapsed Time: 2:06
Miles: 42 miles
Average Cadence: 84 rpms
Average Speed: Just over 20mph

As soon as I rolled into the house, I stripped down and hopped on the scale, shocked to weigh in at 167 pounds! That's right ... despite drinking a full 118 fl oz or about 7 lbs of fluid, I had still lost 3 lbs. of fluid in just over 2 hours of moderate training!  Wow! I knew I was a heavy sweater – but this 'experiment' really served to illustrate that fact vividly. 

Any way, my point in sharing this experience with you is to remind you to pay special attention to your hydration needs during training and racing, especially when it's in the heat of summer. The difference in the way I felt today, when I drank a ton, was incredible compared to how I felt on Saturday, when I severally under-hydrated. 

The take home lesson – discover your sweat rate and do your best to maximize your hydration for peak performance!

Coach Troy Jacobson, the founder of the Spinervals Cycling Video Series and a former pro triathlete, is the National Director of Endurance Training at LIFE TIME FITNESS. With over 80 fitness centers throughout North America, LIFE TIME FITNESS offers a full array of multisport training programs and services for the recreational and competitive triathlete. For more information, visit www.lifetimeendurance.com or www.lifetimefitness.com