Friday, August 10, 2012

Running on Empty

Sunrise from atop Fishkill Ridge (Tuesday)
It's hard to believe, but after a long season of training and racing the Virgil Crest Ultra—a major focus of my ultra-running each year—is only six weeks away! Needless to say, I'm excited. For one, it's the focus of the Gluten-Free Ultramarathon Challenge, which raises money for the National Foundation for Celiac Awareness. For another, it's quite simply an awesome race: very challenging, on beautiful trails, with great volunteers.

After taking one week off to let my legs recover from the Escarpment Trail Run, I've resumed my training with a vengeance. I'm focusing on two things: a) building strong mountain legs by clocking lots of vertical, and b) putting in long distances on the trails to further build my endurance and get my legs used to running through fatigue. I've been waking at 5:00am on weekdays, and depending on the trailhead, I'm on the trails running between 5:30 and 6:00am.

The Hudson Highlands have, thus far, been my main training ground. West of the Hudson River, they serve as the venue for the North Face Endurance Challenge at Bear Mountain, where I set a 50-mile personal record earlier this year. My training, however, has been focused on the Highlands east of the river. There three contiguous and large parcels—Hudson Highlands State Park, the Beacon Incline, and Fiskill Ridge—provide exceptional trail running opportunities with lots of serious vertical. To gain the tops of the ridges typically requires a climb of at least 1,000 vertical feet, and in many places—such as at the Beacon Incline—you gain that 1,000 feet in just one mile. For those unfamiliar with trail running, one word summarizes that scenario: steep.

In the span of three days this week (Tuesday through Thursday) I logged 9,500 feet of elevation change on the trails, with runs ranging from 6 to 12 miles. Tomorrow (Saturday) will be my longer run of the week, somewhere in the 20- to 25-mile range. Over the course of the next few weeks, that long run will push into the mid-30s for mileage.

Sugarloaf Mountain from Breakneck Ridge (Wednesday)
When people—and especially other gluten-free athletes—find out that I'm a runner, one of their first questions is often something along the lines of, "What do you eat?" In fact, it just happened to me earlier this week, when I was "introduced" to another gluten-free runner on Twitter. The person's first tweet to me was, "What's your favorite pre-race meal?"

My answer to that question varies depending on a number of factors: Are you talking about what I eat the morning of? Or the night before? Are you talking about for a specific race? Or generally while training?

For example, my pre-training meals for this week's runs may surprise some people. I ate nothing. No breakfast. No gels. I basically rolled out of bed and hit the trails, running on empty. I carried a single 20-ounce bottle of water with one scoop of First Endurance Electrolyte Fuel System, which provides about 100 calories during the run. Immediately afterward, I downed an 18-ounce bottle of water with two scoops of First Endurance Ultragen for recovery, which provides a targeted 300 calories. Then, I ate my breakfast. But nearly all of those calories were consumed after the workout. Why? There's a method to my madness...

Crossing the Vanderbilt Estate on the Hyde Park trails (Thursday)
Endurance athletes get their energy from two basic sources: carbs and fat, either in your food or in your body. The harder that you're training (approaching your VO2 max and approaching or surpassing your aerobic/anaerobic threshold), the more that your body depends on the carbohydrate part of the equation (converting glycogen stored in your muscles into glucose for energy). There's just one problem: you only have so much glycogen stored in your muscles and liver. Once it runs out, you "hit the wall" or "bonk." You can try to replenish it, by consuming simple and/or complex carbs during your workout, but you have to keep the calories going in, which can be harder and harder to do over the course of a long ultra when you lose the desire to eat.

Fat, on the other hand, is an excellent source of energy. Gram for gram, and pound for pound, it provides more than twice as much caloric energy as carbohydrates. Unlike the limited supply of glycogen you have stored in your body, even elite athletes with little perceptible body fat have enough fat calories in their body to keep them going like an Energizer bunny. As you might guess, though, there's no free lunch. It's harder and slower for your body to recruit energy from fat, and if you're pushing too hard, your body will preferentially go for the glycogen and carbs.

Ultramarathoners are a unique breed, however. Running super long distances may be extremely difficult, but at any given point in a race or training run, you're not running all that fast. You're pacing, so that you can go the distance. Well, since you're performing at a fraction of your limit, your body is able to start to recruit fat for energy. And if your body is doing that, you a) are tapping into a great source of long-lasting, slow-burning energy, and b) taking some of the burden off your muscle glycogen and the need to replenish it constantly.

Here's the really cool part: in the same way that you train your muscles to build endurance, you can also train your body to burn fat better. How? By running on empty. When you wake up first thing in the morning, your muscles have naturally lower levels of glycogen (since, unless you grabbed a midnight snack, you haven't eaten in a good long while to replenish glycogen levels). Then, by going out for a training run before you have anything to eat, you deplete those glycogen levels even further. This forces your body to start burning fat, and over time, your body learns to do that better and better. (Just don't go crazy with carbs in your diet, because overdoing it in the carb department can offset the fat-burning mode you've taught your body to employ...)

If a run is long enough and challenging enough, such as tomorrow's planned 20- to 25-miler, I'll of course have to pay close attention to my nutrition and fuel my body accordingly. But for weekday morning training runs that are easier—for me right now, anything pretty much half marathon distance or less—I'll worry about eating after I'm done.

Sometimes, it turns out, appropriate gluten-free nutrition comes down to eating nothing at all.

–Pete

For much more detail on this topic, including the science behind it, check out The Gluten-Free Edge: A Nutrition and Training Guide for Peak Athletic Performance and an Active Gluten-Free Life.

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