A few days ago, I was browsing around and came across a blog post by TJ Tollakson - the person who won the Lake Placid Ironman in 2011. To be honest, I normally don't read much on these things because they usually talk about stuff that doesn't much apply to me, and things that are only interesting to those who are elite athletes. I figure they get enough attention, they don't need mine. This time, however, it was different. I'm not sure whether it was because I saw him cross the finish line in person, or what - but I was compelled enough to read it. Or at least, to start.
It started out like I'd expect - events he did leading up to IMLP, fancy equipment too expensive for me to afford but that would help his time, yadda yadda yadda - but before too long, it started getting interesting. He started detailing what he ate before, during and after the event. Suddenly, there was something he was writing about that I could relate to. I may not have the training, equipment, or inherent talent that he does - but one thing I can optimize is how I fuel during a race.
My plan for IMLP in 2012 has always been to take full advantage of the support. They will be having sports drink available every 10 miles on the bike, and every mile on the run. My plan was to down a 24 oz bottle of sports drink at least every other aid station, and possibly grab half of a banana at the other stations - something like that. That would equate to 24 oz per hour of sports drink, minimum (at my pace) - and plenty of potassium. Normally I don't end up consuming quite as much on my rides simply due to logistics and availability of water. Then, on the run, I'd grab some more during my walk breaks every mile. In fact, I was figuring I'd be better hydrated and energized during that race than at any point during my training.
So, back to the blog post - what really stuck out to me, after reading all the stuff about a gel every 20 minutes, having caffeine halfway through the bike, was the comment that he got off the bike and felt almost as fresh as he did at the beginning of the bike.
Let me repeat that: He finished a 112 mile bike ride, and still felt energized enough to, as he put it 'rock a solid marathon'. The fact that he did the bike ride in a stupid-fast 4:33 (25 mph on one of the hilliest IM courses in the world) is just gravy on top.
I think that stuck out to me because I don't care who you are or what training you've had - you are going to feel a 112 mile bike ride.
Now, obviously his power output on a bike far exceeds mine, for a multitude of reasons: he's got a coach (I don't), he's got a tri bike (mine is a road bike), he's trained far more than I have, he's an elite athlete (I'm an average Joe), etc, etc. The list goes on and on. But that list is a list of things I cannot change (well, realistically, anyway - I'd like to keep my day job and continue living in a nice neighborhood). What he did do, though, is make sure he was loaded up with fuel. That is something I can change.
A few years ago when I started this whole triathlon thing out, my friend Dave convinced me pretty quickly how important sports drink was for endurance. However, I didn't put a whole lot of stock into the number of calories, because it seemed a small fraction of how many would be needed. For example, you have a marathon at 26.2 miles. For most people, thats going to equate to about 3300 calories required for that effort. If you drink 24 oz of sports drink per hour, and it takes you four hours - you end up with 96 oz of sports drink. Most drinks are about 50 calories per 8 oz, so you end up consuming 600 calories. Sure, 600 out of 3300 is a decent percentage (about 18%) - but it certainly isn't where the vast majority of calories are coming from.
Now if you look at TJ's calorie consumption - he ate 15 gels in the 4.5 hours of the bike. Cycling requires significantly fewer calories per mile than running; running generally equates to about 125 calories/mile, and cycling is often closer to about 45. Sure, each of those vary from person to person, and the numbers vary with intensity and equipment - but we are ballparking here. So each energy gel is 110 calories - meaning he consumed over 1600 calories on the bike alone.
So, the rule of 24 oz of sports drink per hour provides 150 calories of fuel per hour. TJ consumed about 360 calories per hour on the bike - more than twice the caloric intake. That is a significant difference.
But that's not all. In my recent exploration of fueling for endurance events, I browsed through the 'Running for Fitness' link that I have on the sidebar of this blog. This was an example of a page I stumbled across before, found it imformative, and just flagged it for review later without really processing what it had to say. I found section 7.3 - "Energy While Running", and suddenly a bunch of things started clicking in my head all at once:
"You can store about 400g of glycogen in your muscles, and about 100g in your liver (though, as we shall see, these can be increased with training). This means you can store about 2000 kcal as glycogen – enough energy to run or walk about 20 miles."
Well that there pretty well explains the dreaded wall at 20 miles for a marathon. However, my wall ocurred a few miles later during the Baystate Marathon . I only consumed a total of 48 oz (6 x 8 oz bottles) of gatorade during that marathon, which accounted for about 300 calories (or 2.5 miles). In fact, its worse than that because I mix gatorade at about 2/3 to 3/4 strength. But either way, the timing of when I hit the wall vs how many calories I consumed is just about perfect.
"The aerobic energy system primarily uses a combination of carbohydrates and fat (but can also use proteins). The proportion of carbohydrates and fats used depends on the intensity of the exercise. For low intensity exercise, your muscles mainly draw their energy from fat. But as your effort level goes up and your muscles have to generate energy more quickly, so you have to increase the proportion of energy that comes from carbohydrates. The proportion of energy provided from carbohydrates rises as exercise intensity increases from around 10% to up to 90%."
My HR during that marathon was generally between the 75-85% range. So if the amount of carbohydrates required goes up with intensity (up to about 90%, where it switches from aerobic to anaerobic), then I was in a mode where the majority of my calories needed to be carbohydrates. That leads back to the previous point, where I only provided my body with an additional 300 calories of carbohydrates. In effect, I was starving myself of carbs.
Then there was this bit that started to tie it all together (bolding mine):
"During the first hour of exercise, most of your energy comes from glycogen stored in your muscles. After about an hour, the muscles begin to draw their fuel from the blood sugar, which is in turn supplied by glycogen stored in your liver, as well as from their own stores. Your liver glycogen levels are also finite. So when your liver glycogen is depleted, your blood sugar level falls and you are unable to carry on exercising. This low blood sugar (called “hypoglycaemia”) induces a feeling of tiredness and light-headedness, and your legs begin to feel very heavy. Marathon runners know this as “hitting the wall” or getting “the bonks”. It is a quite distinct (and unpleasant) feeling, and it has the same effect on your running performance as a large bear climbing on to your back.
But if you can replenish your blood sugar while you are exercising, you will not deplete your liver glycogen stores so rapidly, with the result that you can carry on for longer before you hit the wall. That is why it is a good idea to take energy on runs of more than 2 hours."
This is where I got into forehead slapping territory. Durrrr... Just one of those moments when I realized that all those times during long training runs that I felt like I was running out of gas - it wasn't that I needed more training to push beyond the limits I had found. I just needed to do a better job of fueling my body.
Then, finally, there was these bits in the last section:
"Research shows that the average person’s muscles can take up about 30g to 60g an hour of carbohydrate from the bloodstream."
--snip
"It takes about 30 minutes for the carbohydrate which you eat or drink to reach your bloodstream, so you need to start consuming carbohydrates before you begin to feel tired."
--snip
"consume about 35g of carbohydrate per hour, which will roughly maintain your blood sugar levels."
Thats a lot more carbohydrates than I've been taking in during long runs and bike rides. The problem I had was that during bike rides, opportunities to refill water bottles in order to consume that many carbs in the form of gatorade were relatively few. This has me thinking that I might have to re-evaluate how I get carbs during long rides and runs. It may be that energy gels are a higher density form of carbs that can more easily be consumed in the proper amounts per unit time. Another option might be to go with gatorade full strength (or even more) - but honestly that gets too sweet, and I know that I'll be wanting nice cool, fresh, unflavored water on those rides and runs in the middle of summer when it is hot out. So I think that possibility is off the table right away.
I'm starting to see why they say that sports drinks are good for anything over an hour, but not necessarily for the long haul as the primary form of fuel during a marathon.
Coming up in the next part - now that we've established the importance of fueling during exercise, we take a deeper look at fuel sources.
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