Fueling long run

Lietchi
Lietchi Posts: 6,892 Member
in Fitness and Exercise
I've been running for a while now, but my runs are getting longer and I think I'm not fueling adequately.

I didn't usually fuel at all for my runs because most of them aren't that long. But I first had an issue after a 17km run (anything up to 12km was fine) where I felt fine during, but nauseous and weak starting a few minutes afterwards. Low blood sugar and/or lack of electrolytes?

So yesterday I did another long run, took a quick toilet break after 11km and ate a gel (sugar+electrolytes) before getting back on the treadmill. But I started to feel faint around the 18km mark. Took a short break and ate another gel and finished the remaining 2km (20km total) but I still felt a bit faint.

I'm wondering if my gels weren't enough? Do you know of any guidelines regarding how many carbs and/or how many electrolytes I should take in depending on the distance/duration?
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Replies

  • spiriteagle99
    spiriteagle99 Posts: 3,750 Member
    It depends partly on how warm it is. How much are you sweating? If you sweat a lot, you will need more electrolytes, possibly salt tabs. You will also need to drink more.

    Do you have issues with orthostatic hypotension? I find that when it's hot I get dizzy when I stop suddenly. It takes a few minutes for my blood pressure to get back to normal.

    Do you eat before your runs or do you run fasted? Eating something light before the run (i.e. banana or juice) or a meal two hours before your run should give you enough carbs to fuel a run of 20k. Most people don't actually run out of glycogen for about 20 miles. If not, a gel every 45 minutes to an hour should provide what you need. Eating and drinking something immediately after a long workout is a good idea, though if you pushed your limits you may not feel hungry right away. Some Gatorade or juice or banana can help with both glucose and electrolytes.
  • Lietchi
    Lietchi Posts: 6,892 Member
    spiriteagle99 wrote: »
    It depends partly on how warm it is. How much are you sweating? If you sweat a lot, you will need more electrolytes, possibly salt tabs. You will also need to drink more.

    Do you have issues with orthostatic hypotension? I find that when it's hot I get dizzy when I stop suddenly. It takes a few minutes for my blood pressure to get back to normal.

    Do you eat before your runs or do you run fasted? Eating something light before the run (i.e. banana or juice) or a meal two hours before your run should give you enough carbs to fuel a run of 20k. Most people don't actually run out of glycogen for about 20 miles. If not, a gel every 45 minutes to an hour should provide what you need. Eating and drinking something immediately after a long workout is a good idea, though if you pushed your limits you may not feel hungry right away. Some Gatorade or juice or banana can help with both glucose and electrolytes.

    Ah, thanks for the input!

    It isn't terribly warm currently (garage, around 60°F/15°C) and I don't think I sweat profusely, although I do use an electrical fan which perhaps aids evaporation.

    I do have hypotension: always quite low blood pressure, sometimes feeling faint while standing up too (less frequently since I increased my salt and potassium intake). And I know I need a gradual cooldown period after a long/hard run as well (going from a run to the couch is guaranteed to give me orthostatic hypotension when I get up again). But the faintness I felt seemed a different kind.

    In yesterday's case: I ate a meal at 2PM (50gr of carbs), ate 2 satsuma's right before running at 6PM (I think, if I'm not confused with the day before). I drink while running (just regular water).
    I always run right before dinner, so fueling afterwards is OK.

    From your message, I gather I shouldn't have/didn't run out of glycogen considering the distance and having had some gels. Perhaps electrolytes are the more likely candidate and I should be drinking water with electrolytes instead of plain water? Looking at the numbers, I wonder if my gels aren't too low in electrolytes to use only them.
  • spiriteagle99
    spiriteagle99 Posts: 3,750 Member
    How hard are you running? Do you feel like your long run pace is really easy, conversational? I tend to push my effort too much, which isn't an issue on shorter runs, but when the runs get over an hour, I feel more tired than I think I should. I know, from what I've read over and over, that the problem for me is largely that my easy runs aren't really easy. They are more moderately hard. I can sustain the pace, but it wipes me out. Could that apply to you? Especially since you used to run a lot, you may be trying to run at the pace that was good a few years ago but isn't now.
  • sarabushby
    sarabushby Posts: 784 Member
    A gel every 40mins should be fine for fuelling. Anything over 1hr you might want to consider taking gels for, starting at the 40mins mark. You could experiment with trying a few varieties to find one that works best for you and they do vary in as you say, electolytes as well as calories.

    I have real problems with post exercise orthostatic hypotension sometimes and it’s seemingly made worse by having a carb meal after the exercise: I read why and think it was to do with blood going to the digestive tract.

    It can be a real nuisance after my Saturday swim sessions which are always followed by lunch out… then I try and go shopping and heaven help me if I need something from the bottom shelf of the supermarket aisle!
  • TxDesertFox
    TxDesertFox Posts: 53 Member
    I've had the same issue this past marathon training season. The dizziness I had more on the treadmill, not sure what it is but I hate being on the treadmill. The light headedness and feeling weak for long runs (outside) was more of an issue for me during the summer so I hydrate and fuel more in the summer. I'll take salt tablets and energy cubes every 30-40 mins after the first 40 mins. I also used to run fasted or on little food, but since stopped doing that and found having oatmeal, peanut butt and toasts have helped. Honestly, what I found really worked for me on long runs was something I saw on Instagram by another runner -- graham crackers. I hate gels so I break the crackers into smaller size and put the in a plastic baggy and use them for fuel instead of the gels.
  • Mrsrobinsoncl
    Mrsrobinsoncl Posts: 128 Member
    For me, fueling the day before a long run is the most important. During the run I will have a gel after an hour, or 45minutes if I feel like I'm dragging some. I use salt tabs on hot days
  • Lietchi
    Lietchi Posts: 6,892 Member
    edited March 2023
    Some interesting things mentioned.

    Running pace. Well, that's probably the biggest thing. My running 'program' is basically what I invented for myself, not really knowing anything. After some googling and too many articles giving long run paces based on (target) race times, I finally found a useful suggestion. Apparently long runs should be 65-75% of 5K race pace. I don't do races, but I figured using my PB would be a good equivalent (only distance that I occasionally test/push myself in). And that's definitely slower than what I've been doing. Just going from 8.6kph to 8.2kph felt better already last week when I did 17.5km (just above 75% of my 5KM PB).
    Perhaps slowing down my long runs will also kickstart my progress, my VO2max estimates have been stalled for a while.

    I like the graham cracker idea too (I love crackers anyway :smiley: ) as an alternative to gels.
    I've also checked the gels I was using: one type had way less salt than the other, so I won't be buying those again - I know I need a lot of salt to keep my BP up.

    In my case I don't think the food I have the day before is the issue (plenty of carbs and calories before my 20km session where I felt faint) but definitely something to keep an eye on too.

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