I went to a nutrition presentation by Dr. Arnie Baker this evening, very informative.
http://treksandiego.com/site/page.cfm?PageID=59
At the end, in the QA session, I asked about nutrition for a 40k time trial event (states/nationals).
He said NO FLUIDS OR FOOD for the event, and I should pre-hydrate extensively.
I have not heard this before, but it got me thinking.
Looking for comments and experience on this topic.
Thanks!
I’ve heard this for 20 kms but not 40 kms before. Could be tough on those hot humid scorching summer days. Pre-hydrating extensively makes a lot of sense.
I’ve thought about this too. In 1-hour sprint tri’s and du’s I never have any drink. I never drink on a hot, hard 1-hour training run. But, I’ve wondered what is the right thing to do.
How much sweat can we lose in an hour? A liter, is it? Figure a half a liter low can begin to inhibit performance? That means a half liter of drink keeps us on top of the game. If I drink 16 oz of fluid 15 minutes before an event – that should work.
I always start long runs with at least that much fluid in me. I have guzzled a quart of Gatorade right before a long run in the hot sun. It works very well.
Arnie is a very, very smart guy who doesn’t say much of anything about anything unless he has really checked it out.
I’ve never had luck with pre-hydration, because then I need to take a leak just when I’m motoring. I “pre-hydrate” with about 16oz. of some sports drink (usually Hammer Sustained Energy) about 15-20 minutes prior to race start. Kidneys tend to shut down when you’re hammering, so I don’t need to pee until after an Oly or mile 2-3 of the run on a half and then only once.
I wouldn’t go without fluids for a 40K unless it was pretty cold outside. Since I tri, the 40K is preceded by a swim and followed by a 10K run. The equivalent might be a sprint tri of about 1 hour, and I drink during those, but not a lot.
I might be able to pull it off, but mentally I need to drink. If you look at pics from Nationals, most riders carried a bottle. I may fill 20 oz into a camelbak bladder and slip it under my skinsuit, flat, sans backpack.
The only reason I carried a bottle last weekend was because I was testing it out on a 20k.
317w average only got me 29:20, rode out of the aerobars a lot in very muddy conditions.
http://www.printroom.com/ViewGalleryPhoto.asp?userid=clinster&gallery_id=142733&image_id=31
Gary, I feel the same, my colleague UKGearmuncher is an uber Time Triallist and doesn’t use water for a 10 mile, not sure about a 25. I can’t do that even if it is only a 1/2 filled 500ml bottle I take, I need to be able to keep my mouth lubricated. Also, if “tonking” my fluid loss is significant toward dehydration.
How do you keep the bladder from slipping to one side or falling if you don’t use the pack?
I was a participant of a study in an exercise lab last year. We had to do a 30km hilly TT on a computrainer. During one of the trials we weighed me pre and post exercise. It took me 47min to complete that trial. During that time I drank 1000ml of water. After the exercise I weighed .6kg less. A total loss of 1600g. Yes, not all of it is water but a good amount. The lab was 20C, and I had a fan in front of me the entire time. I was soo hot and sweated like crazy. There is simply no way I could have kept up with my power output if I wouldn’t have had consumed all that water.
It doesn’t take that much physiology knowledge…
Cardiac output = HR x Stroke volume
Sweating reduces the total blood volume which reduces venous return. Less blood volume returning to the heart causes the stroke volume to decline.
In order to sustain a certain power output you have to deliver a certain amount of oxygen per minute. This can be measured in terms of VO2 with a gas analyzer. The amount of oxygen delivered to your muscles depends on the volume amount of blood pumped per minute (cardiac output). Now, during an all out 40km TT you are already pretty high near your HRmax. Let’s take Dr. Arnie Baker’s advice and NOT consume water during the TT. How do you think you can sustain the required cardiac output to maintain performance? You will reach a level where your HR plateaus. With the HR staying constant and the stroke volume declining, what will happen to the cardiac output? Yes, correct, it will reduce.
Not consuming water and therefore allowing a great reduction in stroke volume will be performance detrimental.
edit. I edited some of the text. I was kind of pissed off at a situation non-slowtwitch related and started my reply somewhat unrespectful. I apologize.
sweet bike 
.
Not consuming water and therefore allowing a great reduction in stroke volume will be performance detrimental
I love when people make pseudo-medical sounding replies that are total BS =).
Scott
I must agree with Cousin Elwood, pre-hydration ALWAYS makes me pee. If I had to choose, I’d choose being slightly dehydrated at the start and drink an entire bottle, else I’ll be uncomfortable the whole time.
-Colin
Is that you in the picture Gary? Those don’t look like rotors.
-Colin
ok, then tell me what happens to the total blood volume when you sweat but do not re-hydrate?
http://www.xtri.com/article.asp?id=838
Confirms more or less what you said but this relates more to the IM. Still interesting.
and I love it when people reply to a post calling it BS without having anything else to say. Tell me, why do you think it is BS?
Daniel
Gary, I’ve done lots of timetrialling in the UK, and not drinking in a 25 (ie 40 km) mile TT is normal - from the fastest riders to the slowest. If its very hot then I might take a drink, but even then I would probably only do that for an event taking over an hour, rather than a 25. Arnie is right - prehydration is enough, drinking during the event can use precious time and can be more for psychological reasons than physical.
"Is that you in the picture Gary? Those don’t look like rotors. "
Yes, and they are the new RS4X Ti model.
What were the reasons he gave for not drinking during a 40K TT?
"What were the reasons he gave for not drinking during a 40K TT? "
My body did not need the water, as I will not lose enough to impede performance
I could not get it down anyway, to be effective
My goal TT time is 54 minutes, and it was not needed for such a short period of time
Did he go into how to pre-hydrate extensively?
When I played soccer in college, we’d do a 30min warm-up, grab a sip of water. Play a 45min half, get a sip at halftime, and then play another 45min w/o getting anything. Never thought anything about it. So 2 hours w/o any substantial water consumption.
So for all sprint tri’s I take a little water to clean out my mouth after the swim. I throw more water on myself than I drink probably in events under 2hr. No cramping or any problems. It’s mental really. Like hitting that Gu in a sprint tri.
In training I always have water and gatorade no matter how short. Think about fueling/hydrating for tomorrow. Like how the guys in the Tour really are eating for the next days stage, not for right then.