HHH ....HAZY, HOT AND HUMID! This accurately describes our weather pattern here in the Mid-Atlantic for the past few weeks. Endless summer days of hazy sunshine, 95 deg. temps and 70% humidity, driving the heat index up over 100 deg.! I can believe it but I find myself sometimes looking forward to a typical January day, feeling the sting of a cold blast of air against your cheeks and the crackling of ice and snow under your boots as you scrape the frost off your car window. Remind me I said this in January, OK? :)

Last week I was out riding one of my favorite loops, a hilly route that takes between 2 hrs 15 minutes and 2 hrs 30 minutes, depending on my intensity. This day, the heat index was over 100 degrees and I was feeling strong and had a hard ride planned. Before the ride, as I usually do, I weighed myself to monitor my fluid needs for rehydration purposes. The scale read 175 while wearing only my bib shorts. I wanted to get a handle on my current sweat rate.

So I went out on my ride and felt good, clicking off a nice high aerobic and sometimes anaerobic effort in the hills. I carried two 20 oz bottles with me filled with water and a Gel for energy replacement. For rides under 2.5 hrs, I always feel good with only two water bottles and I thought this ride would be no exception, despite the heat that day. After all, it's been hot lately so I'm acclimated with plenty of heat training, making the body more efficient and able to deal with heat more effectively.

After 30 minutes into the ride, I looked like a had taken a shower with my cycling clothes on. The humity was so high, my socks and shoes were soaked with the sweat running down my legs. I had to discard the sunglasses as they became so covered with salty sweat, I could barely see through them. Bottom line...it was very hot.

The nice thing about cycling in the heat vs. running in the heat is that the air moving against your body at 18- 22 mph makes you feel more comfortable and the activity more tolerable. Ever tried doing a spinervals indoors with the heat at 100 deg. and no fan?? ... not fun.

So I finish my ride and I'm smoked. Not only from the pace (which was hard) but also from losing some serious fluids. Both my 20 oz bottles were emptied during the ride. I ran upstairs, stripped and jumped on the scale to see how much weight I lost. The scale read 168 lbs! I had lost 7 lbs of sweat while still consuming 40 fl oz in only 2 hrs and 20 minutes for a gross wt. loss of about 9lbs! At that rate, I most likely would have started cramping and cracking had my ride gone a few more minutes.

Here are my stats:

Ride distance: approx. 40 miles
Temperature during ride: 100 deg (heat index)
Avg. HR during ride: 140 bpm
Pounds lost during ride: Gross wt. 9 lbs. / net wt. 7 lbs.
Fluid consumed during ride: 40 fl oz (approx. 2 lbs)
Fluid I need to consume during such a ride: 144 fl oz or about 3-water bottles /hr

One of my athletes sent me a training report today that indicated a similar finding...but he managed his fluid intake during his ride. A larger rider at over 200 pounds, he rode for 60 miles in 3 hr 40 minutes with an avg. HR of 136 and avg. power output (watts) of 156. The temps were in the upper 90's with high humidity.

During his ride, he consumed 188 fl oz (almost 10, 20oz bottles of water and gatorade) and 10 oz of Gel. After his ride, he weighed himself again to find that he did not gain or lose a pound! A 'perfect' balance! His consumption of fluid and gels equaled about 12 pounds (16 fl oz = 1 pound of fluid) or in other terms, he had to drink just under 3 - full waterbottles per hour when riding to maintain an equilibrium.

I recommend that you perform a test to determine your fluid needs. A one hour test near your 'race pace' intensity will do the trick. I always say that most people will require between 40-60 fl oz / hr when training hard in hot (80deg. temps and higher) conditions, depending on body weight and other factors. Note however, that stomach emptying can be hampered when the body is under stress from high exertion, heat and the anxiety of racing so make sure you experiment to discover your personal needs.

Train safe and train smart,
Coach Troy

p.s. Don't repeat my test of 2:20 hrs with little water. I am a trained professional and do stupid experimental things like that as part of my job and the benefit of my athletes :)

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