I recently replaced running with biking for my workouts. Reason being, I get very light headed and my feet feel the burning sensation quite quickly into my run. After I run (lets say 4 miles), I feel dizzy and my head is not in a very pleasant feeling. I understand the burning sensation in the calves and legs would slowly get better and better with more muscle. I'm curious as to what causes the fatigue and the light nauseous feeling after running? I had the same thing happen the first time I went on a 10-15mile bike ride, but it only happened once when biking. I get this feeling every time after running.

Feel free to add tags that I'm sure I've missed. Thank you.

  • 2
    Frankly, it sounds to me like you're hitting low blood sugar. Are you certain you're eating enough before exercising? Jul 29 '15 at 18:42
  • @SeanDuggan Yes, I make sure to eat a proper breakfast and lunch, then I take it easy and eat a lighter meal for dinner.
    – MB41
    Jul 29 '15 at 18:50
  • When do you run in relation to your mealtimes? As @SeanDuggan says, first thought is low blood sugar, second thought is lack of proper breathing (Barring some congenital defect, of course).
    – JohnP
    Jul 29 '15 at 21:43
  • 1
    Have you checked with you doctor? The first step is to get medical clearance for exercise. There can be a number of causes of feeling lightheaded and having burning feet. Because these occur during your run, not just after your run, you would be better off checking with your doctor. If everything checks out ok, then you can modify you eating schedule, hydration, and monitor your heart rate/exertion levels. Jul 30 '15 at 5:06
  • 1
    @MR04 - Not really, no. Not as a daily standard, anyway.
    – JohnP
    Jul 30 '15 at 15:14

It could be blood sugar but since its summer it could be a lack of water in combination with heat and the meal sitting in your stomach. It takes some water just to digest your food too. I get nauseous when I run after eating, and usually the afternoon can be the warmest time of the day. Ive learned how to deal with this but usually for longer runs; time-wise. You should start running in the morning if possible when your food is digested and energy stores are ready. Plus breakfast would be right after a run to help balance the blood sugar :)
I don't think you'll get a straight answer on this since the source can be so many things. Here is an example of throwing up that is related to eating and running.

  • Thank you for the help. It was the water. I figured this out through biking. I started taking longer and longer bike trips and only taking 1 bottle of water. It got to a point where I felt light-headed just like running. Then I started to freeze a second bottle of water and take it with me. By the end of my bike trip, I realized that both the water bottles are practically empty and my body felt great! So I started taking a small strap-on bag with extra water on my runs and it helped greatly! Can never have not enough water :)
    – MB41
    Aug 17 '15 at 12:50
  • P.S. I'm trying really hard to run early in the mornings (at least on weekends), it's just hard because I have to be at work at 7am at times. I don't like running on a full stomach though...But thank you for your response.
    – MB41
    Aug 17 '15 at 12:53

You are probably suffering from dehydration. Four miles is a lot to run, and 15 miles is a lot(for most people) to bike. You can start to sweat after even just a half mile in hot weather or in other heated environments. If you have loss of balance or/and fuzzed vision, that raises the chances of the sole cause being dehydration, too. DRINK PLENTY OF WATER!!!

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