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At what mileage is refueling necessary? (Read 1797 times)

    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?
    ---- Cynthia
      I don't find it helpful to take in any calories unless I'm running 14-15 or more miles. I have friends who swear by taking gels/gus on runs from 6-10. Maybe give it a try on a 7-8 mile run and try again without and see how you feel. Regarding water - I used to run up to 8-10 miles without water - in cooler temps. Then summer hit and I wouldn't even do a 4 miler without water. Now I bring a hand-held water bottle for every run regardless of distance or temperature. Maybe it's habit - maybe it helps. I feel better with the water bottle - and thats what matters to me.

      When it’s all said and done, will you have said more than you’ve done?


      Imminent Catastrophe

        You probably should start carrying water now (or plan to get some along the way) since you're out for over an hour. You don't really need carbs during a run unless you're going for more than 3 hours or so ("the wall"), since your body has enough stored to last that long. They might help you to get a better workout, though. Another alternative is to have your carbs immediately before you go running.

        "Able to function despite imminent catastrophe"

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        √ Tahoe Rim Trail 100M 20/21 July 2013

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          I think a lot of your water intake depends on how hot it is. I usually bring water or stop at water fountains on any run longer than 6 miles. As far as fuel, I'll take a GU on a run longer than 10. I don't always feel like I need it, but I want to get my body used to having them during a long run (especially if you plan to use one during your half). I don't usually eat anything before my long runs, so sometimes I get hungry out there after awhile.
          Ed4


          Barefoot and happy

            For water, it depends mostly on the conditions. For food, it depends mostly on your pace and level of aerobic fitness. In both cases you just need to learn to listen to your body. For me, I only carry water when it's fairly hot out or if I'm going 18+ miles. I only carry food on fast runs over two hours. At a relaxed pace I can go over two hours and still not get hungry. In fact, some people use hunger to gauge whether they're running at an appropriately easy aerobic pace. If you get really hungry after only an hour or two, you're burning a lot of carbs as opposed to fats. The fats last much longer.
            Curious about running barefoot? Visit the new barefoot running group.


            Blaine Moore (MM#2867)

              For myself, I rarely carry water unless I'm running on trails (which tend to be a bit slower) or I am running 15-20+ miles. I never take any sort of food unless I'm running 18+ miles. If it is really hot out, then those numbers come down; realistically, though, when it is really hot I am changing my workouts around so that I can run at a cooler part of the day.

              Run to Win
              24 Marathons, 17 Ultras, 16 States (Full List)



                Thanks everone, I knew I would get some great advice here! Cool
                ---- Cynthia


                Another Passion

                  You probably should start carrying water now (or plan to get some along the way) since you're out for over an hour. You don't really need carbs during a run unless you're going for more than 3 hours or so ("the wall"), since your body has enough stored to last that long. They might help you to get a better workout, though. Another alternative is to have your carbs immediately before you go running.
                  I used one GU on a 12 mile run today at mile 6 and I think it helped the last half of my run tremendously as compared to the last long run I did which was 11 miles. In the last long run, I was getting gased pretty bad physically at around mile 9 and on todays run I pushed right through and actually increased my pace a bit. Felt much better physically as well. That's what it did for me on a not so long long run. I do feel it helped my workout and, I want to get used to taking the GU's on runs so they don't make me ill in the marathon I am training for in April.

                  Rick
                  "The will to win means nothing without the will to prepare." - Juma Ikangaa
                  "I wanna go fast." Ricky Bobby
                  runningforcassy.blogspot.com

                    I typically run 7.5 miles. Sometimes I'll need water if I'm feeling particularly bad, but those are rare occasions. I've never felt the need for calories, however.
                      My general rule of thumb is if I'm running longer than one hour, I begin carrying water. Weather also plays into this - I am much more efficiant in the cooler/cold weather than in the heat. I sweat a lot and therefore lose a lot of fluid in the hotter temperatures.
                      "You can't have everything. Where would you put it?" - Steven Wright
                        I stopped in the running store today and checked out some fuel belts. I will be putting that on my list to Santa!!
                        ---- Cynthia
                          Cynthia! I read your forum topic because I too was wondering the same thing... when I looked at your log/profile I realized you too were from Little Rock!!! What a small world... the LR Marathon 5k was my first race last year too. I'm training for the HM in March as well. Cool Are you training with the schedule off of the lr marathon website? I have seen different ones, I can't figure out which to follow.
                          ~Sarah~ My 2008 Goals: Little Rock HM (just finish it :)) Nike Women's Half Marathon San Francisco 10/19/08 5k < 30:00>


                          A Dance with Monkeys

                            Short answer: Depends on your effort; but at a submaximal pace you should not need any calories for about 15+ miles if you have been eating adequately. Long answer: Your body contains about 2000 kcal of energy stored as glycogen and another 4000 kcal for EVERY pound of fat you have (e.g., a 150 lb person with just a 5% body fat will still have almost 8 lbs of fat, worth about 32 000 kcal!). Energy expenditure while running is a function of your weight, and to a lesser extent the grade of the road, and to a far far lesser extent to your pace. So an 8 m/m runner is burning energy at about the same rate PER MILE as a 12 m/m runner with the same weight while they are both running. A 150 lb runner will burn approximately 120 kcal per mile run. Your body uses two fuel sources to run. One is glycogen. Glycogen is the primary energy source used for fight or flight type activites, which means it is the primary energy source used when running. When you run above 80-90% of your maximum effort (or VO2max, or Maximum HR), your body is burning almost entirely glycogen to fuel the effort. Below that, your body starts using the other energy source, which is fat. An innacurate but useful rule of thumb is that your body fuels its effort using glycogen as a percentage of total calories used that is equivalent to your perent effort. So if you are running at a 70% effort, about 70% of the kcal you are using to fuel the effort are coming from glycogen, and the rest come from fat. The reason you bonk is that you run out of glycogen. If you weigh 150 lbs and are running 80% effort, you will use about 2000 kcal worth of glycogen in about 21 miles. If you are running at a 70% effort, it will take you 24 miles to use 2000 kcal worth of glycogen. So why do you bonk at mile 18? Well, even if you carb load absolutely perfectly (and most of us do not), when you finish loading, you then go to bed and sleep. When you wake up marathon morning, your body has used up as much as 25-30% of your glycogen just keeping you alive overnight. And the next morning, the little bit you are able to force down into your stomach, well it does not ever get a chance to be stored as glycogen. Calories on the run? Sure, there are two general options. There are sports drinks, which deliver 4-10 kcal per cup, depending on how dilute the mix and how full the cup. And there are gu or jelly bean packets, which deliver about 100 kcal per packet, provided you can get every last bit. It takes about 1 1/2 packets of gu or about 15 cups of sports drink to fuel each additional mile (i.e., spare your body's need to burn glycogen) When you bonk, you slow down. When you slow down, your body preferentially burns fat. That is how you can finish, even after bonking. So, putting it all together, assuming that you weigh 150 lbs (thereby burning 120 kcal per mile), that you are running your marathon at 75% effort, and that you are able to store 2000 kcal, but that you also slept during the night and burned 25% of those calories, but that you take enough gu and sports drink to get 2 extra miles: ((2 000 kcal glycogen * (1 - 0.25 burned last night)) / (120 kcal per mile * .75 effort)) + 2 miles from carbs on the course = 18.6 miles You will bonk at mile 18.6. Or so. It is never quite this predictable. You can also attenuate this by long-term training (which increases your total body glycogen storage abilities and improves your fat burning at high exertion over time). *** When you are exercising at a high level, approaching your Vo2mx, your body cannot digest as well. This is primarily because your blood is pumped away from your gut and to your muscles. In this situation, even gels are hard to digest. This is why, when you run a 5k at a 5k effort, you may even have trouble with sports drinks. Gels are for efforts probably between 75-90% maximal effort (like running a marathon). At lower efforts relative to your Vo2mx (such as training runs, ultramarathoning or walking) you should be able to digest solid foods, although simpler is better while exerting yourself. There is also a limitation to how quickly your body can absorb the calories that you consume. I understand that the ceiling is about 3-400 kcal per hour during exercise, while most of us burn 5-800 kcal per hour depending on weight, pace and terrain. The good news is, at lower pace, we burn stored fat, which provides about 4000 kcal per pound (or, about 5-8 hours of effort per pound). Most of us have at least a pound or two of fat on us. We burn relatively less fat at higher efforts, which is why we cannot depend on this energy source during a marathon. Not until the bonk, that is. For training runs, you should be able to take in any simple carb source. Gels are good if you want something portable. I personally prefer Little Debbie Oatmeal Pies or Star Crunch bars. I will also occasionally have a nut/granola bar, a banana or banana bread. I usually only have these during the run if I am running over 14ish miles, although I did a 20 the other day with no calories on the run other than a few cups of gatorade (~<50 kcals worth). if you are bonking on your marathon training runs, you are running them too hard and/or you are not taking in enough calories in your daily life. kcals="" worth).="" if="" you="" are="" bonking="" on="" your="" marathon="" training="" runs,="" you="" are="" running="" them="" too="" hard="" and/or="" you="" are="" not="" taking="" in="" enough="" calories="" in="" your="" daily="" life.=""></50 kcals worth). if you are bonking on your marathon training runs, you are running them too hard and/or you are not taking in enough calories in your daily life. >


                            Another Passion

                              Awesome, Trent. Thanks for the info. I knew of this, but didn't know the physiology or dynamics. Very helpful.

                              Rick
                              "The will to win means nothing without the will to prepare." - Juma Ikangaa
                              "I wanna go fast." Ricky Bobby
                              runningforcassy.blogspot.com

                                Cynthia! I read your forum topic because I too was wondering the same thing... when I looked at your log/profile I realized you too were from Little Rock!!! What a small world... the LR Marathon 5k was my first race last year too. I'm training for the HM in March as well. Cool Are you training with the schedule off of the lr marathon website? I have seen different ones, I can't figure out which to follow.
                                Sarah, what a small world! Yes, I am following the Half Marathon training schedule from the LR marathon website: http://www.littlerockmarathon.com/Training/TrainingSchedule.cfm Generally I do my training runs during the week on the TM at the gym and then on Saturdays I meet the running group listed for Little Rock. You can register to get on the email distro here: http://www.littlerockmarathon.com/TrainingRegistration/index.cfm (it's a huge group, I think around 100 people!!) Trent - that is great info, thanks. So far I'm still working up to 8 miles and not refueling. I am hoping Santa brings me a fuel belt for water though. Cool
                                ---- Cynthia
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