Fueling during marathon; important?

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This topic contains 9 replies, has 6 voices, and was last updated by  randys 14 years, 6 months ago.

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  • #1444

    randys
    Participant

    Sunday I will be running my 6th marathon. In my prior races, and during training, I never used gu’s/gel’s or sports drinks.

    It seems that many posters, on various sites, stress the importance of refueling during the race when offering advice or when explaining why they had a poor race performance (hitting the wall stuff).

    In many cases people are using gu’s and gel’s to run 1/2’s or even 10k’s where I am certain they have no benefit. I am less certain of there usefulness at the marthon distance although I don’t feel I have ever ‘hit the wall’.

    While I have slowed somewhat during the last 10k I have not been slowed to a walk (generally less than 60 seconds off my initial pace) which I have blamed on a too ambitious a pace overall and not on ‘the wall’.

    I have no plan to change anything drastic going into a race in 4 days but am interested in what others think about the need for fueling during a marathon. I know that I tolerate sports drinks well and since it is offered on course this Sunday I may consider drinking it.

    Am I in the minority by running and training only with water or is it more common than the forum postings would have me believe?

    btw: I understand that at distances beyond the marathon fueling is essential but it seems that 26.2 miles should be within the range of your stored glycogen.

    What do the rest of you do?

    Randy

  • #14338

    Ryan
    Keymaster

    If I remember correctly, when running at marathon pace, one can expect glycogen stores to run out at about 20 miles, give or take, if you are not taking in any calories during the race. This would mean that, if you don’t slow down a bit to conserve that glycogen in the first 20, you’re running on fat for the final 10k. That or take in some calories along the way to make your glycogen stores last longer.

    At this point, I would definitely not suggest changing your fueling plan for your upcoming race. You simply don’t have enough time to practice any changes. I know I wouldn’t be confident making such a change so close to a race. Also, you know you can accomplish your goals for this race without the calories from a sports drink or gel. I would suggest sticking with water for now, many marathoners did quite well with just water before sports drinks were used, and experiment with sports drinks and/or gels in the future to see if you can reap any of the benefits of additional calories on the go.

  • #14339

    Ed 1
    Member

    Have you read anything about people dying for hyponutremia? This is where the body lost all of its sodium and shuts down and dies!!! This has happened in numerous marathons including last years Boston. I would suggest replacing some of the water stops with Gatorade or other electrolyte replacement drink. The GUs/Gels make me vomit for some reason so I avoid them. I did eat candy corn (very little) about 15 minutes prior to mile 20 with no problems. But if you train without stay without except for the idea of occasional electrolyte drinks to replace those. Your body cells run on sodium and potasium pump systems for firing – deplete enough of one of them and you would be in a serious life threatening situation. Tons of water flushes the body with no replacement – especially bottled water. Be careful and stay safe. Good running.

  • #14340

    danm
    Member

    First of all, I am living proof that you do not need to practice drinking or eating GU’s during the actual event. It is no big deal. Here is a link to a great article by Owen Anderson and if this doesn’t make you change your mind about whether or not to consume some sort of supplement during the race I don’t know what else would.

    http://www.pponline.co.uk/encyc/0173.htm

    and

    http://www.pponline.co.uk/encyc/0015.htm

    I had heard from another friend (a 2:35 marathoner) about the article and how he had used it for every marathon with great success.

    Basically it involves drinking Gatorade (or another similar electrolyte replacement drink) starting right before the marathon and drinking continously throughout the entire race. My friend told me that I would finish the marathon and have to pee immediately and then every 15 minutes afterward for the next few hours. I couldn’t believe it to be true…until I tried it.

    Drink Gatorade at every station you can until you can stomach it no more. This usually occurs around 21-22 miles for me. After that you will need no more.

    Another method is to use water and GU only, no Gatorade as Owen describes. Getting the correct GU and water amounts is the tough part and why an engineered drink like Gatorade is better.

    Personally I could not fathom running a marathon without drinking or eating something as it is scientifically proven that you will run out of glycogen as Ryan stated around 20-21 miles assuming you run the marathon fast enough.

    Dan

  • #14341

    r-at-work
    Member

    the original “wall” calculations of runners not having enough glycogen stores to make it to the end of a marathon were based on relatively young, fit men… those who had already done enough long distance running to train their bodies to utilize fat to some extent even before their glycogen stores had run out…

    if you are running more than 3 hours no matter what the distance re-fueling may be necessary, it becomes more important the longer TIME you run, no matter how slowly

    the brain can only use glycogen… hence the ‘stupid’ feeling later in long races…

    hyponatriemia: deadly… what is interesting is that in the ’70s when I was riding horses competitively everyone was taking salt tablets, then that went out of fashion when it was found that salt contributed to high blood pressure…

    bottom line… know what your body needs…

    personally I don’t use anything till over ten miles or two hours or if I FEEL like I need something… some days it just takes more to get there…

    -R

  • #14342

    Ryan
    Keymaster
    Ed 1 wrote:
    Have you read anything about people dying for hyponutremia? This is where the body lost all of its sodium and shuts down and dies!!! This has happened in numerous marathons including last years Boston.

    Tons of water flushes the body with no replacement – especially bottled water.

    The pendulum has swung. Not that this isn’t a real concern but the concern has been far overstated recently. Most of the hyponatremia cases have been reported in people who run marathons quite slowly and would stop and drink multiple cups of water at every mile marker. They were drinking over a gallon of water on the course, which is quite different than what I suspect Randy has done in the past and intended to do for this marathon. It’s definitely something to keep in the back of your mind but I have a feeling Randy has to be much more concerned about many other factors than he does about hyponatremia. Having run 5 marathons previously with nothing but water says a lot about how much Randy has to worry about this.

    danm wrote:
    First of all, I am living proof that you do not need to practice drinking or eating GU’s during the actual event. It is no big deal.

    You are living proof that you don’t and I am living proof that I do so which one of us is living proof of what Randy needs? Even on training runs, I can feel my stomach start to churn after drinking a sports drink when I haven’t done so on the run for a while. If I were to do so in a race without building up to it, I would be spewing by the second or third aid station. I have gotten better over time but Randy hasn’t had that time to build up to it. If the choice is between running a few minutes better and getting sick on the course, I’m going to suggest playing it safe, especially since he has 5 marathons experience using just water, and then figuring out what works in training when the stakes aren’t as high.

  • #14343

    Anonymous

    Have to say Randy, that I run most winter training runs with little or no refueling. I have no trouble going 20 without water, gatoraide or gu. I did take a gu a few times in training to get my stomach used to it.

    My strategy was to duck tape two gu’s and take them with water at 10 and 20 miles. One fell off off so I took one gu at 13, flushed with water and took gatoraide 4-5 other times. I took nothing for the last 5 miles.

    Hard to say if my strategy hurt or helped. I was hurting at the end but I don’t think it was because my stores were depleted.

    In my opinion, refueling helps for anything over 30k but you need to find what works during training. You also need to adjust for the conditions. It was 50 degresfor my race but I definitely would have done something different for Boston.

    I agree with Ryan, don’t try to do something new in your race. If your comfortable taking in gatoraide I would try and stick with that.

  • #14344

    randys
    Participant

    I am aware of the effects caused by over consumption of water during a race. In my case it does not apply.

    I drink 1 cup at each aid station; I even skip a station or two if they are too congested. So that’s about 12-13 8oz cups in a race.

    Steve, I also run during the winter without water or fuel for runs up to 20 miles. Even in warmer weather I have no trouble going at least an hour without water.

    I always fuel an hour or so before I run long (over 20). I usually eat a canteloupe (not a slice, the entire thing, minus the rind), a bananna and 1 or 2 ‘soft pretzels’. I drink a bottle of sports drink and a bottle of water too. It adds up to about 1000 calories.

    This has been my routine for long runs since I began running.

    I asked about fueling because I got an email this morning from the race directors announcing that sports drinks were going to be readily available at all aid stations on course this year (unlike prior years).

    While I did not train with sports drinks for this race; last summer I did my long runs as loops, stopping home every 8-10 miles and drinking a sports drink. It did not cause me any trouble so I could probably tolerate it during this race too.

    Considering that training has gone well I probably will run like I trained; perhaps taking some sports drinks later in the race. I do appreciate the advice from everyone and will post my results on Monday.

    btw: It looks like it will be raining on race day. I am trying to feel good about that but its not easy. I did a 24 mile training run in the rain several weeks ago and finished in what would have been a new PB if I had run the final 2.2. I keep reminding myself of that and the fact it will keep us cooler (expected temps are high 50’s) so it may work out for the better.

    Randy

  • #14345

    sub3marathon
    Member

    the brain can only use glycogen… hence the ‘stupid’ feeling later in long races…

    -R

    The brain prefers glucose, but can use other substrates. The glycogen in the muscle is of no use to the brain since there is no way for the glycogen to leave the muscle. Glycogen stored in the thighs cannot be used anywhere else except the thigh muscles.

    However, liver glycogen and carbohydrate ingested during exercise are available for use in the brain.

  • #14346

    randys
    Participant

    I have never experienced that ‘stupid’ feeling at the end of a marathon. As I said I feel fatique building over the last 10k and that has forced me to slow during the final miles; but not to the point of walking.

    And after the finish I always spend another 15-30 minutes walking before heading to my car. Even during that time I usually only drink water and grab a bagel or two for the ride.

    I always assumed my weakness over the last 10k was a result of training too slow compared to planned race pace. Thats why my average pace for long runs over the last 6 months have been lowered to within 20 seconds of race pace. I hope that will make all the difference on Sunday.

    Randy

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