Fainting after a long run

Training for the FLM and yesterday completed my 22m long run. Was fine after, spent the day sitting about not doing much.
Took an aspirin before going out for a curry in the evening, whilst there I suddenly developed a painful headache, 10 minutes later I started to black out (whilst sitting down), tried to get some fresh air and fainted once I got outside.
Spent the rest of the evening in bed nursing my monster headache.

Was probably a combination of the aspirin, a warm room and digesting food, but does anyone else suffer from this? I obviously need to take it easy after a long run, but how long does it take to recover?


  • m.ittenm.itten ✭✭✭
    Did you take on enough fluid whilst running?

    I've often had a monster headache after a long run. Was that you were taking the asprin for in the first place?
  • Yes, had about a pint whilst running and drank quite a bit afterwards, mostly lucosade too.

    The aspirin was to calm down the aching on the front of my right shin (which I'm hoping isn't shin splints).

    I don't think the headache was due to dehydration more the fainting. I'm guessing my blood pressure dropped to cause the faint but why does a long run bring it on?
  • Low blood sugar?

    Did you take energy drinks / gels during your run? Had you had plenty to eat after the run?

    If not, it is likely to be low blood sugar levels.
  • monkey, it's not uncommon for this to happen. Th reason is that whilest you are running your hear rate rises & so does your blood pressure. Stopping dead after the long run lowers your blood pressure which can sometimes make runners light headed & faint.

    The risk of this is greatly increased if one decideds to consume alcohol as this being a depressant also lowers blood pressure - sort of doubling the risk. It's not been uncommon for many marathon runners / Tour De France racers do enjoy a glass of bubbley as they cross the finish line only to nose dive straight into the tarmac almost instantly.

    This may or may not have been what happened to you but it's something to consider.

    Low blood sugar is also an option - did you feel sick? The brain need glycogen (blood sugar) to function & when you stores are dangerously low (20% 'ish) the brain send out an early warning system & you bonk - ie, you feel dizzy, nautious, you may even get sick / faint if you choose to ignore the warning & soldier on. However I think it's probably unlikely as you fueling with lucozade which, even post run, should get into your system pretty fast
  • Hi there Monkey,

    Funny as I was just about to post a similar message so I thought I'd tag on to yours instead, if you don't mind.

    I did my last long run today (18 miles) and felt pretty much ok during the run. Got home, started stretching and then felt incredibly nauseous and like I was going to faint. I figured it was low blood sugar so went to start making some lunch, only to pass out on the living room floor. I forced myself to cook but then couldn't eat anything because I was feeling so nauseous.

    Finally managed to eat after a lie down and am feeling much better now so I'm fairly sure it was low blood sugar. My question is how can I keep my blood sugar level on a long run if I am feeling nauseous? I had a small bottle of SIS drink on the run and attempted to eat a bit of a sports bar, but couldn't stomach it (began feeling sick at about mile 15). I actually felt my stomach rumbling about 2 hours into the run. The SIS itself is ok, I think (the Lucozade didn't agree with me), but I can't seem to drink that much of it.

    Any advice?

  • don't take aspirin after running. Your blood pressure is reduced after running and aspirin will lower it further. Do you know what your normal BP is?
  • My BP was 110/60 last time I had it checked, which I think is on the low side of normal.

    The odd thing is that I'd been fine straight after the run, I'd eaten a meal and several chocolate bars throughout the afternoon (plus plenty of water) so I thought I was over it. It was later that I felt faint, I guess it can take longer than you think to recover from the very long runs.

    Point noted with the aspirin and the alcohol, think its best to hold off on anything like this until the day after.

    Sorry to hear you had the same thing Janey, have you tried Gels? They're a new thing for me but I find they do give you a kick and they're easier to get down than an energy bar. Also, straight after the run I usually shove down a load of berries, blueberries are my fav. and some dried fruit n nuts - seems to hit the spot until I can get the energy back to cook. I couldn't eat after I'd fainted either which just adds to the problem.
  • I haven't tried gels, but I think it's too late now as I've done my last long run before the marathon so don't really want to try them for the first time on the day. Thanks for the advice on the berries and nuts, I'll give it a go.
    Hope you're feeling better.
  • I can never eat anything after a long run as I usually feel sick and just not hungry but I do make sure that I have a recovery drink straight away as these go down easily.
    I always make sure that I have eaten really well the day before I run too. And re-fuel the following day when I know I can eat. I make sure I have lots of snacks every day too. You need to eat enough calories throughout the week to fuel your run not just on the morning.

  • I suspect a fluid situation here. Is a pint during a 22m run sufficient?

    Not for me it ain't!
  • A fortnight ago i did a twenty mile run and got home feeling a little nauseous. I got in a hot bath way too soon and just after climbing out i barfed !! Felt a lot better afterwards though. I usually get a headache in the middle of the night and put it down to not rehydrating properly.

    The hot spicy food of a curry might just have been too much for your stomach to take following such a strenuous activity.
  • I had an issue during a 16 mile training run. Yes I was fine the rest of the run, then

    Suffered a bout of dizziness and a migraine during the final mile.

    When I got to the car I ate my banana, drunk water, still felt deflated.

    I did not feel better until I had a lie down then lunch.

    I have taken into account what other readers have said. I will carry some children's

    Lunchbox jelly and yoghurt pouches to maintain my blood sugar and a water bottle

    Doing a long run next time.

    I think I would find the sports gels over poweringly sweet and sickly.
  • And it took 10 years to respond 

  • I recently ran a 10 mile run a few weeks ago but when I finished just walking in to my home catching my breath and even before hydrating myself standing just a few minutes standing by my kitchen counter I suddenly fell and for a matter of minutes fainted and causing my ankle to twist thus a displaced sprain . I had to drag myself and was on the floor for about an hour😆so now I’m on crutches few weeks later and hoping for a fast recovery so I can continue my running. Texas weather has been at its highest🔥and humidity at least 50% so I’ve had my challenges 😢this summer 2022 sadly but never give up. I see now after reading these articles that I totally understand . Any suggestions are much appreciated👍🏻
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