OK, so you've done several marathons now and wonder what to do next. Seems like you have 2 options available to you. First is to improve your marathon times by going faster and maybe qualify for Boston. Not a bad goal, what happens when you feel you're getting up there in age and don't want to bother with the speed workouts.
Luckily, more and more people are starting to choose Option 2, go the ultramarathon route. And in the whole scheme of things, it's quite practical for those who want to discover what the real joys of running are and to challenge themselves in a way that, if done properly, can reduce your chances of injury (low impact running, but that is a different subject).
But what do you need to know about ultras? There are some key differences between the 2. The key differences are 1) The rate of ingestion during the race, 2) The type of food you'll be eating during your race 3) Your carbo-loading dinner 48 hours before the race, 4) Your overall pace of the run, and 5) your cirdacian rhythms over the long hours of the ultra.
Since this is a long and comprehensive subject, I'll post each subject one blog at a time to make it easier for you to understand.
The Rate of Ingestion During the Race
OK, this is a very important factor, one that bears reading multiple times until you grasp the importance of this one. Remember your marathon, where you run by the aid stations, grab a banana or energy gel, or a cup of water, and keep within your stride. You don't eat much during a marathon, relying on the nutrition that you built up in your carbo-loading and what you ate the morning of the race. Just a little energy is needed during the race to get yourself to the finish. Most everyone who finishes the marathon is depleted in their energy reserves; if you ask them to go another 5 miles, they cannot do it very well.
Well, that is because the energy you expend during the marathon is greater than the energy you ingest. All marathoners end up tapping into their reserves for energy. If done well, you exhaust your reserves at or near the finish line, for those who didn't plan well, they "hit the wall" at around mile 21 and struggle to the finish.
So fuel reserves for the average person is worth about 21-26 miles. So if you tap out at mile 25, all you need to do is will yourself over the last mile to finish the marathon.
Now, what would happen if you "hit the wall" at mile 25 of a 50 mile ultramarathon? You'll be up the nasty creek without a paddle, wouldn't you? Ready to struggle another 25 miles to the finish? I didn't think so. It wouldn't be a nice predicament to be in and surely one that you need to avoid.
So scrap your marathon strategy because it doesn't work with ultras. You need to come up with a completely different plan to get you to that 50 or 100 mile finish line. If your reserves are limited to 20 miles and you have a 50 mile race, the extra 30 miles worth of energy is going to be needed from food ingested DURING the race. And since it takes some time for your ingested food to be converted to readily available energy, you need to eat early and often in an ultra.
Luckily, most races have aid stations that are set up for this; you'll immediately see the difference between an ultra aid station and a marathon aid station when you come upon one. As you see below, you will not see an aid station fully stocked with a wide variety of foods in a marathon:

(this aid station comes from the Tarawera 50mile ultra, yumm!)
(Just one thing on aid stations, it is always beneficial to have other options if the food at the aid stations doesn't work for you. A lot of ultramarathoners use their own crews that provide a personal aid station with foods the runner knows will help him or her out. It pays to have a couple of people to help you out during these races).
So what is the ultimate rate of ingestion needed for a 50 or 100 mile race? The same amount that is expended during your run.
If you cover 5-6 miles per hour in your ultra, the amount you expend is about 500-700 calories, depending on body type, so you'll need to eat that much to keep going. For 50k, a little less in needed because it is only 5 miles longer than a marathon. In a 50k, you still have to significantly change your eating habits because who still wants to hit the wall at mile 21 and struggle a full 10 miles to the finish?
That amount of calories ingested could pose a problem for some people. How do you eat that much food while running? How do you know you've eaten enough calories? And what type of food can you eat to keep you going?
That is the subject for tomorrow's blog. Until then, Happy Trails!