At what mileage is refueling necessary? (Read 1799 times)

See, I have been kind of nervous about going with the training program, because I'm scared that I am too slow and they will all run off and leave me!! lol I had no idea that there were near 100 people in the training group on Saturdays... I signed up for the training, and get "mama hobbit's" emails, but haven't been on Saturdays. I've been running my long runs on Fridays... good info!! I will have to show up for one! Yeah, I plan on running the half, kinda nervous, but surely won't finish last!

Hi...I'm originally from Hot Springs, but living in Arizona now. However, my best friend (Greg) runs with that training group on Saturdays (at least he used too...He's rehabbing an injury now). Anyway...He says it's great..There are people of all skill levels out there. So go, in other words.

In regards to refueling; if you're training for a marathon/half marathon, I'd play around with the idea of NOT refuleing during the long runs. Greg McMillan has writtten, I believe, an article about it in Running Times (or somewhere else). I've discussed this with him as well; as well as some other people like Lorraine Moller (bronze medalist in 1992 Olympic marathon). During the long runs, you're training your body to go through the wall; basically, switching your fuel sysgem from glycogen, after you run out of it, to fat. Fat produces much more energy per molecule but it requires more oxygen to burn. This physiological change is known as "the wall". The smoother you can switch, the less hard you'll hit it. Refuleing during the long run simply means you will be feeding your body more glycogen (or energy) and never tap it into your fat burning system. Now, in a strict physiology sense, this is probably not quite true because if you're running very slow, you are most likely starting out with fat burning system anyways. In other words, your hitting the wall during the marathon has more to do with tired legs. Basically, as someone else said before, we all have plenty of energy in our body to run a couple of marathons over; the issue is, can we use that energy more efficiently? Once again, if you continuously feeding yourself during the run, your body may never learn how to use your stored energy more efficiently.

Nobby, I like your style. And I agree with most of what you said. Not sure I buy the idea of training yourself to go through the wall, though. Training and proper race pacing is all about not hitting the wall in the first place. That particular McMillan article gets referenced all the time when this topic comes up and I think even Greg McMillan has admitted there's not much science behind it. The notion that you can train your body to burn fat more efficiently by depriving it of carbs is sketchy. That you can train your body to burn fat more efficiently by training, however, is pretty well established. And for that reason, completing the day's workout and doing so strongly is the most important thing. If that requires taking in some fuel on the run, then I say go for it. I agree with you that most people worry way too much about hydration and fueling--as you pointed out, due to the commercialization of the sport. Hydration and sports-related food-like substances are big business. Like you I never cary water--I'll plan my routes to go past water fountains on hot summer days maybe--and I almost never carry gels or other things unless I'm going very long. But if you're doing a 20 mile training run that includes some serious changes of pace, odds are you'll need some fuel to finish the workout strong, especially since during marathon training most of us start out each day with less than a full tank of glycogen anyway.

Yeah but Nobby's post was after your'n. Plus I couldn't find any hairs to split in your post (possibly because it contained scientific abbreviations and percentages and such, which scare me.)

disclaimer: hey, i'm a weirdo. even according to noake's statistics. something that no one has mentioned here is that there are two systems at work during your marathon or long run. one is the muscular system, which uses locally stored glycogen. the other is the brain and central nervous system, which uses glycogen stored in your liver and glucose in your blood stream. my experience with bonking (and i have more than i wish i had) has been that my brain and cns run out of fuel. and i've found out the hard way that your muscles can be well-trained and packed full of glycogen, but if you can't generate the contraction impulse with your brain and cns, it doesn't matter... you can't run, you bonk. i tried to train myself not to bonk, averaging 40, then 45, then 50 miles per week for the entire year leading up to three goal races, with peak weeks in the 70's then 80's miles (on single daily workouts). and i had two, then three speed sessions per week, sometimes long runs of 26 miles, fast finish long runs, 15 milers at mp, etc. etc. so you can imagine my frustration when during three races in a row i bonked at 2 hours. started as a slight headache, then i'd feel light-headed, get tunnel vision, and just completely lose focus. i'd be reduced to a run/walk, eating and drinking everything i could get my hands on. i still thought it was training or mental, but then looking at my heart rate plots, they were identical... within a few minutes in each race, i'd start to slow down, and i'd decelerate at exactly the same rate, no matter the course/weather/training. bonk. then i read noakes. my symptoms were consistent with running out of fuel for my central nervous system. i'd run out of liver stores after two hours, then slowly burn through blood glucose volume. when that ran out i'd bonk. the next day... no problems... no doms, no tired muscles... no nothing... like i had muscle glycogen to spare. so noakes says 5% of marathoners deplete their liver stores (so 95% of you reading this don't care) before 26.2 miles, and i'm one of them. i did some computing, and realized i wasn't drinking enough sports drink to make an impact. so i started taking gels, and haven't bonked in the last two marathons. in a race i gel early and often, 100 cals every 30 minutes. now a marathon is just another race for me, albeit longer and harder, instead of some mystery bonking bad dream. so there's a lot of good info here about muscle glycogen use, and training. but there are a few of us that run out of glycogen supplies for our nervous system (i haven't found a way to change that with training), and benefit enormously from digesting carbs during a race. to answer the original question: during training i don't use gels, except for the weeks leading into a race. then i take them during a couple of long runs, and also some race pace sessions, just to get used to getting them down... makes it easier on race day.

I am slowly moving up my mileage on my "long runs" (training for HM in March 2008). Right now I am at 6 miles and next weekend I move up to 7. So far I've not been carrying water or food with me. At what mileage point is it generally recommended to refuel?

It's not necessary in training. Force your body to use its fat stores. I'll go 22 miles and up to 3.5 hours without taking anything but water.