Is it dangerous to run a marathon without taking any refreshment during the race?

Sorry about the long title, was about as concise as I could make it. I thought about putting this in GQ as I’m looking more for facts than opinions, but as it leans towards medical advice it had better go here.

The background is that I have always struggled with eating/drinking before/during exercise. I remember as a child always having dinner after football practice, for example. As an adult, I’ll happily go for a run at lunchtime of 5 miles plus on no breakfast or lunch (just water), but as I have increased the distance of my runs in training for my first marathon next month, obviously I’ve been trying to fuel up a bit more.

My longest runs so far have been 14 miles (during which I managed to force down 2 sports jelly beans with about half a bottle of water), 18 miles (1 sports jelly bean with water, felt awful for the last few miles), and 22 miles (had breakfast of a bowl of Cheerios with milk, and a banana 2 hours beforehand, plus water, just one sip of water during the run and still didn’t feel good).

I think my problem is reflux - I know the digestive system essentially shuts down during a long run, and it seems mine doesn’t even want to swallow. So on the evidence so far, I’m minded to have a similar breakfast before my marathon, but not bother taking on any liquid or food during the race, unless I feel thirsty (I haven’t felt thirst during any of my runs to date). The weather is likely to be cool on the day (certainly under 15 degrees Celsius) and possibly wet.

A little light Googling suggests this is not necessarily crazy - found a couple of sources saying 14 people have died from over-drinking, but none from dehydration, and the current sports science favours drinking when thirsty rather than keeping to a set schedule. I just wondered if any of you Dopers can add further insight. Thanks in advance.

Milk sits terrible in my stomach pre-workout. The same with bananas. I would suggest foods that are more carbs. Things like apples, oatmeal, grits, etc. work pretty well for me. And eat 1-2 hours before your workout so it has time to digest.

You can do a marathon without eating. Your time will be affected, but you can do it if you listen to your body. Drinking water is something you should not skip. It’s possible, but it would be dangerous and you’ll have more struggles if you don’t drink. Your body can keep using fat for energy, but once it sweats out all the water, it won’t be good. And things won’t work as efficiently as your body gets dehydrated.

Before your run, get very well hydrated. Drink enough so that you have a strong need to pee before you start. Your pee should be light yellow.

On your training runs, try drinking small amounts of plain water frequently. Drink early in your run before you feel the need or your body gets stressed out. Plan out how much you should drink over the run and make sure you are hitting those targets. If you can handle the water, you can try adding some sort of electrolyte powder for some calories. It may be easier to drink calories rather than eat them.

Also, one reason you may have trouble eating on the run is because you’re dehydrated. Your body needs water as part of the digestion process.

Are you training with a running group? If not, maybe consider joining one. The coaches can give advice on how to get your body better able to handle food/water on your runs. When is your marathon?

Drinking when thirsty seems in general a good idea for distance runners, as opposed to drinking at every water station whether you feel the need or not. And agreed, there’s evidence that overdrinking poses more of a risk than dehydration, due to potentially serious hyponatremia.

I would be uneasy though about a modestly trained individual going an entire marathon (especially on a mild to warm day) with minimal to no fluid intake.

*"Many runners can recall the hot day at the 1982 Boston Marathon when American Alberto Salazardrank no water and secured a narrow victory. He needed intravenous fluids in the postrace medical tent and observers speculate the race wrecked his running career.

Current guidelines from the American College of Sports Medicine call anything greater than a 2% loss of body weight during exercise due to dehydration “excessive.”

“At the point that you sense thirst, your physical performance and cognitive function are beginning to decline,” says ACSM president-elect Lawrence Armstrong of the University of Connecticut.

He points to findings that even 1.5% dehydration can affect performance, and says that athletes should craft individual plans based on their rates of sweat loss and fluid intake per hour."*

And while some accounts of dehydration-caused deaths during races are disputed, there are accounts of such things happening.

I would avoid going to extremes when it comes to fluid intake.

Maybe you can get by without eating but you had for sure better not go without drinking any fluids during the marathon. Water when thirsty, and also Gatorade and a bit of salt to prevent hyponatraemia.
It is, after all, a race named after an incident in which the soldier died after completing the run.

Thank you all for your replies.

Interestingly, this was the part I was most concerned about (the having breakfast beforehand) and it was fine - no digestive issues at all. Whereas sometimes I have run after eating and been forced to curtail my run for a sit down toilet break. Good advice about going for more carbs, though. I should add that I had made sure to have a very large bowl of noodles the night before.

I think I achieved this, too - I drank enough before the race that I peed three times in 2 hours, and I still felt I needed to go for about the first 10 miles. So will definitely look to replicate that.

The problem is, it seems to be swallowing anything at all that I have difficulty with. If I could swallow water, I could do the same for Gatorade or whatever. But I guess I’ll keep trying. I guess I just haven’t practiced it enough, since I tend not to even consider taking water for runs under 10 miles.

Not as such, but I go running with a group at work, most of whom are pretty well-versed in this, so I’m getting good advice from them, too. The race is in 4 weeks so I still have a little time to do something about the issue.

I take your point, and “modestly trained individual” is certainly a fair description of me, but the day is likely to be cool/cold, with every chance of rain. Plus, I can’t read your cite as it is paywalled for me, but it seems to be advocating less to drink rather than more, which doesn’t seem to be the main thrust of your post :confused:.

No doubt this is good advice, I just need to work out how to get the fluids in me without causing discomfort. I think part of the problem may be the excessive amount of mucus/phlegm I seem to produce, even in fairly warm weather. Maybe I’ll try training with a decongestant of some sort (perhaps a generous helping of Vicks on the T-shirt).

Good username/thread combo :). Thanks for the advice, and the warning!

Decongestant will make the mucous or phlegm thicker, which may not be the best thing if you already have a problem with it.
There are expectorants which THIN mucous, but I’m not sure I’d self medicate that way right before a marathon :slight_smile:
I have some problems with thick stuff due to allergies in combination with allergy meds. I sip sparkling water - the soda/carbonation seems to clear the mess out of my throat. But I’m not sure if that’s a good thing to drink during excercise or not. It will add salt to your intake as well as water.

I’ve not done a marathon, but I have run a half-marathon. In training for that, I learned that most runners will deplete their onboard energy resources over the course of a race of that long, and it was strongly suggested that one have some sort of quick energy food to eat during the race, to replenish those reserves.

I know a lot of distance runners who swear by GU Energy Gel, but I tried it, and it was like eating toothpaste. :stuck_out_tongue: I went with Jelly Belly Sport Beans.

This, for sure. What I’ve read is that one should work on that hydration starting the day or two before race day, as well.

The cite goes into the risk of hyponatremia from overloading on fluids during a race, but as you can tell from their account of the marathon runner who needed IV fluids after his race and may have suffered permanent health complications, one can err to the other extreme as well, with serious consequences.

The most common effect from lack of calories is “bonking” or “hitting the wall”. This is where you suddenly lose a lot of energy, your legs may start to feel really heavy, and you may have trouble continuing with the run. Since this is your first run and you’re not efficient at that distance, I would expect your body to be going through calories at a higher rate, which may mean this is more likely to happen if you can’t eat during the run. Be sure you lookup the symptoms and effects so you know what to be aware of.

How does your stomach feel during the run if you drink right before you start? Can it handle the water okay, or do you get distress immediately? If you can drink during the early miles, it may carry you through later on if you have trouble getting water down. And you can always walk a bit until you are able to drink, then resume running. It’s good that you’ll have cool weather, as you’ll lose less water through sweating.

This is probably obvious to most people here, but based on what I see in races, it isn’t obvious to everyone. Do NOT try to drink from that dixie cup while you are running. Stop, catch your breath, and drink slowly. The 10 seconds you lose while standing there is nothing compared to the 2 minutes of choking if you attempt to drink without breaking stride.

I went through uni with this guy.
“Buzzard” was a handy athlete who went for a 8km Fun Run in 1988, didn’t hydrate during the run overheated, cooked and melted. Literally.
He has survived after extensive rehabilitation, and the loss of a leg.
A medical miracle he survived so I’m calling out your claim that nobody has died from dehydration when running.

When I was doing a lot of running, mainly half-marathons, I relied on gels like GU. Once I got past the texture, I viewed them as fuel, and I found them to be helpful at set intervals. I could never handle the blocks or beans - too much chewing, and I would end up coughing them up (yes, I am a mouth-breather during heavy exercise). The gels went down quicker.

I think hydration and nutrition on long runs (and any extended physical activity) is important, as is pre-fuel. I agree about milk - could never have a bowl of cereal prior to a run. I have since switched to almond milk so maybe now.

I don’t think lack of food or water during a run is necessarily dangerous, but your performance is likely to suffer, and you wont feel as good as you might have.

It depends how much one takes in at each water station. When I do a, say, 10 miler, I pretty much intake some fluid at every station but I only take a sip, I throw away probably half or more of what’s in the cup. If you take a couple of full cups at every stop that’s a different story. By taking in a little on a regular basis you not only stay hydrated but also won’t get stomach issues, either feeling like the water is sloshing around or your body not being able to absorb/digest your intake because so much blood/effort is being used by your leg muscles.

It’s not so much that you suddenly lose energy, it’s that you run out of fuel. Your car won’t run w/o fuel, & neither will you. There’s only so long you can go before your body runs out of fuel (glycogen); you’re burning up calories every mile, every hour. You probably need a couple hundred calories an hour to get thru a marathon. Somewhere around mile 20 is when most people run out of fuel & ‘hit the wall’. If you were taking in fuel earlier in the race, hopefully you can get at least another 6.2mi in before you hit that wall.
Dead Cat, I’d recommend trying numerous different products on your training runs, both different types of products (gels, blocks, etc.) & different brands, & maybe even different flavors of a given brand of gel.

18 & 22 miles are long runs, about as long as anyone does other than on race day. I’m not entirely convinced what you did (not) eat was what caused your issues rather than just being at the tail end of an extremely long run. I’d suggest trying something new at mile 1 of a 5 mile run. You can rule out overall fatigue by trying something in that shorter run, & if it really doesn’t work out, well, it wasn’t a long run anyway. You may be able to fit in that last mile or two later in the day if you’re so inclined.

This is me too. I can not eat a good two hours before I swim, nor can I eat anything or drink anything when I’m swimming. I’ve tried multiple hour swims and triathlons, and have always had a hard time even getting water down. I can do it, but it hurts for a good 10 minutes after.

I would say that, depending on the temperature you could get away with doing a marathon without eating or drinking anything. If it’s in the 60s-low 70s it shouldn’t be much of a problem at all. But, if it’s going to be hot or humid you’ll probably have to get some water in to you. You might want to start drinking more water a few days before the race as well.

I have found that I can eat plain oatmeal before a swim, it still hurts a bit, but not as much as most other things I’ve tried to eat. I’ve always wanted to do a nice long swim, but I really need to figure out the eating/drinking part first.

The max amount of carbohydrate you can absorb per hour is pretty well understood - the energy drinks and gel companies make great play on this in their marketing, a figure of 90g per hour 2/1 glucose / fructose is often bandied about. It is good to have a grasp of this, IMHO, as it enables you to structure the gel intake, but I use it more to avoid eating too much (my stomach is pretty resilient during exercise) which sounds like the opposite situation to you.

Fluid intake is more personal and varies wildly with climate, plus you have hydration companies bollocksing on that one must drink like a fish if one is to compete. I once went out to watch my sister in law run the Edinburgh marathon on the hottest day of the year and saw numerous people staggering and a couple of collapses. It was like a George Romero movie - marathon of the living dead. Running in the British Autumn, though, is a different game. If you felt comfortable just sipping when thirsty I think that would be fine, although your intake does seem really parsimonious right now. One sip on a 22 mile run? Sounds way on the low side that.

I used to be a runner but now I’m a cyclist. Every year I do several long, competitive and non-competitive rides (60-100 miles). This is multiple hours of fairly high exertion. I drink (water and Gatorade) and eat (beans, gels, etc) pretty much the whole time. I’ve bonked hard a few times and it isn’t fun. It would impossible for me to run a marathon without both fuel and fluid. Also, without enough salt intake my legs begin cramping (this is cycling - I didn’t have this issue running).

For me personally, I wouldn’t call it dangerous but I’d bonk and not finish.

I showed this thread to my friend, as we were literally discussing his training and race-day plan for a marathon he’s running 2 weeks from now while I was reading this thread. He wanted to reply to Dead Cat and share what he’s learned over the past two years of marathon running and training.

Since it’s long, and since it’s a post from a non-member, I’ll put it in a spoiler box for those of you not interested in what some “outsider” has to say to Dead Cat :slight_smile:

As a marathon runner, let me give you some of the information I have learned to help you understand what the needs of the body are during the race. This information is what I would tell any first time marathon runner.

  1. This is your first marathon. It should be about finishing it, not about the best time. If you have some goals, then that is fantastic, but make them realistic. But the ultimate goal is finishing. What you need to do is try to have the most successful plan to get you to the goal of finishing. Nutrition, water, clothes, stretching, rest, etc.

  2. There is nothing wrong with some walking when needed. Walk through the aide stations so you can hydrate. You MUST hydrate, and you MUST replenish lost electrolytes and calories.

  3. Part of training for a marathon is learning how to handle the calories and water. Your breakfasts should be somewhat light, but good calories (granola bar is great, if you have 1.5 hours before you run, a small turkey sandwich would be great, an apple is nice). I start my long runs (16+ miles) with a banana, nutty granola bar, and a rice krispie treat (I just like them). Milk probably isn’t the best thing. Drink stuff that helps your run. Think of it this way… Your marathon does not begin at 8am in the morning, it should begin a couple days before while you carbo-load, reduce your fats, etc.

  4. Get good rest, you will need it.

But what about the race?

  1. Every mile (whether you walk or run) will consume approximately 100 calories. Our muscles can only hold about 2000 calories of quick energy we use for running. After those 2000 calories are used up, your body has to rely on fat stores for energy. The body cannot consume fat calories fast enough to keep us running. This is called “bonking” when we have used up all the glycogen stored in our muscles. It happened to me around mile 22 on my first marathon and my last 4 miles had an average of about a 14 minute pace or so. It just means you will need to work more. Interestingly, your body mentally tells you it’s too hard, it releases chemicals which try to demotivate you to run (serotonin, maybe? Not quite sure). That is your body playing mental games with you, hence the mental challenge. You can still push through a bonk, but there is nothing wrong with walking. That would be a great time to rebuild some calories and get some sugars in your blood to get you going again. Word of warning, if you take in too many carbs and you aren’t used to it, your body might throw extra water to digest those carbs thus causing you to have to use the toilet. The struggle is real, and there is balance. That’s why I suggest watered down Gatorade, just to give you some calories that should be easy to absorb.

  2. Math time. If we use 100 calories per mile and we can only store 2000 calories, that means right around mile 20 is when you will hit the wall. You need to take in an additional 650 calories during the race in the form of easily digestible sugars. People bring up gels (those are good). I prefer the chews (like gummy bears). But you must take these with water as your body needs water to absorb the sugary goodness and amino acids. Know what, if you can squeak in a banana during the race, that will help replace potassium as well. However, if you are not used to consuming carbohydrates during a long run, the race is not the time to try something new. I would say then that when you drink at the aide stations, you should probably mix water and Gatorade so you aren’t getting a huge splurge of calories.

  3. Typically after 60 - 90 minutes of running, your body will start to shift it’s energy consumption. I’m not knowledgeable on this part of physiology, but I know it happens where your body is switching from the fastest energy into a mixture of fast energy (glycogen) and slow energy (fats). You will probably even feel the moment this happens because you might go “gosh, my legs all the sudden just got heavier and harder to move.” Yup!

  4. Staying hydrated is paramount. You must drink. You don’t have to over drink, but you gotta drink. Walk through the aide stations so you can stay hydrated. Forget your time, concentrate on finishing. If you walk through the aide stations and there are 15 aide stations, you will only reduce your finishing time by a couple minutes. Split gatorade and water if you are not used to consuming carbohydrates during running. Let me give you my personal experience. I did a 20 mile practice run a few weeks ago and drank 3 quarts of water during that run. I did not pee the entire run. After I got home, I peed and it was very yellow. 3 quarts of water is 6 pounds of water… and I was dehydrated. Think about that. Last week, I did a 22 mile practice run and I drank 1 gallon of water. When I went pee after my run, it was the proper color (perhaps still too yellow, but acceptable). I required 8 pounds of water. That means I sweat out more than 8 pounds of water.

  5. Don’t go out too fast. It should feel like you are going slow at the beginning. If you start out going fast, you will burn through your energy too fast. Going too fast will consume glycogen too fast. And if you start out real fast, you tap into a different energy store which (aerobic… hmm, or is it anaerobic, I don’t remember which) which really consumes glycogen. You want to stay slow enough that you don’t do this fast burning.

  6. If you have only had a 14, 18, and 22 long, I’m going to caution you to listen to your body. The problem isn’t being able to run that far, it’s preparing the body for the constant impact. If you are cramping, walk. If you are aching bad… walk. It’s ok to walk. If you only had those 3 long runs, your joints may not adequately be prepared for 26 miles of constant impact. 22 is significant! But I’m just indicating to be cautious and respect what your body is saying. Some aches and pains are common and expected, but if your ache or pain is causing your stepping pattern to change, then that is the indication of something being wrong and you need to walk to work it out. Remember that, if your gait changes (a limp, favoring a leg, etc), then walk some to hopefully work it out. That is your best indicator. Now, if the pain is just pain and your are running like normal, then it’s ok to run through it.

After the race…
11. You better replace that water you lost!

  1. You better replace the sugars your body needs! What’s nice is that after running a marathon, it’s actually the BEST time to eat that sugary snack, like a donut, candy bar, etc. It’s not a blank check to eat as much of that as you want, but definitely enjoy some indulgence.

  2. Stretch. This is when we need to stretch. Don’t be foolish and pass this. You will get hurt if you skip this, but you won’t know it until one day you have an ache that gets worse and worse do to inflammation, then eventually a small tear that the body can’t heal. This is a different topic though, so stretch!

Some other tips.
14. Don’t tie your shoes tight. Keep them loose. Your feet will probably swell and tighten up after many miles. This happened to me on my first marathon and I got bad cramps at 22 which is when I hit the wall (lack of calories). It all plays together.

  1. Look, no disrespect to any of the half-marathon runners here giving advice. They certainly have a lot to contribute. There is a difference though as they require different training schedules. A marathon forces the body to do things that doesn’t happen during a half marathon (the opposite is true as well). You can run a great half marathon without any added calories and still have left overs. That’s not the case with a marathon. No disrespect to the halfs, but this is just an acknowledgement that a marathon is a completely different kind of race. You can’t train for a marathon the same way you train for a half, they are physiologically very different. I’ll put it this way. You can walk a marathon and you will burn significantly more calories than a person who runs the entire half marathon. With that said, the half-marathoners also have their own challenges, such as how to train the body to burn glycogen differently than required with a marathon. For a marathon, we want to conserve our glycogen. For a half, you want to burn that stuff up as fast as possible without requiring the body to switch to fat stores. Totally different training.

  2. I just gave 15 poorly organized points :slight_smile: You don’t have to memorize this, remember it, etc. This is just information to help you understand what you need. It doesn’t matter if you consumed the correct calories, or if your shoes are correct, or what underwear to put on (well, it does, but not really). This is your first marathon, what matters is finishing. Take in the experience. Enjoy it! You are around many people who worked really hard, just like you. Just get it done! The basics to get it done are: 1) drink water 2) have some form of calories during the run (if its in the form of gatorade, that’s fine) 3) walk if your body is telling you to walk 4) have fun, talk to people who are going your pace, etc. 5) stretch afterwards 6) indulge, you just went 26 miles, you deserve a really nice, rewarding meal. 7) You don’t have to think of all this stuff, just go out there and run and enjoy it.

My friend had one more point for the OP, after he re-read the thread:

I noticed that Dead Cat indicated drinking before the race and eating a bowl of noodles the day before a race. That won’t do it. It takes several days for the glycogen stores to build up. It’s more important to eat the bowl full of noodles 2 and 3 days before to give a couple days to absorb. Then, it is most important to hydrate starting 3 days before and maintaining that hydration. You can’t hydrate right before a race, it takes many days to hydrate the body. Side note, when you are carboloaded, the glycogen will hold on to more water. Expect to see your weight go up a few pounds. If your race is on a Sunday, you should be drinking probably 3 - 4 quarts / liters of water a day starting on Thursday. Carb-heavy meals Thursday, Friday. Saturday should be a lighter food day since our body has all it needs, so a nice, nutritious lunch and a light dinner. If you eat a big bowl of noodles the night, it will sit in you and you won’t get the carbs you need from it (it’s a bad move). Lastly, the reason for the extra mucus is most likely from being dehydrated and consuming milk before the race. As runners, we should be drinking 2 - 3 quarts / liters of water a day with a boost of water leading up to the race.

I never cared for the gels and I liked the sport beans at first but found that they produce a thick, sticky spit that needs a lot of water to wash down. I’ve had better luck with gummy products like Honey Stingers and Cliff Bloks. And as mentioned, above, a drink of water helps you body absorb that nutrition. Plain old fruit snacks are great, too (and cheaper), but don’t have some of the extra stuff that the fitness nutrition products have (potassium, I think). So when I’ve used those, whereas I’d usually only take water during a race, I’ll make sure to have some energy drink at the water stops as well. Also keep in mind that if you’re having trouble eating, you can always cut whatever you’re using into smaller bits to make it easier to consume.