Post-Exercise light headedness/shakiness.

Patient: Hi, I went on a run 3 days ago, just like my usual runs. Except this time I hadn’t had any food before the run, nor did I have any food after the run. It was stupid of me I know.But anyway, I finished the run around 3pm and then I felt fine until around 5-6pm when I was on my laptop downstairs and all of a sudden I got a massive rush to my head as if i was going to faint, and my heart seemed to be beating a lot faster than usual. I’ve never had a panic attack, but I can imagine that’s what a panic attack would have felt like? Im putting this down to a lack of energy in my body to handle the stress of the exercise?But anyway, I felt okay after I slept for an hour or two and got some food down me. But that past few days I haven’t felt fully ‘together’. As if my heads not fully there. I mean, I can walk around, and talk to people and everything is usually normal, but sometimes I feel a little light headed as if it’s nearly going to kick off again.So im just curious as whether its normal for me to feel ‘odd’ a few days after such an experience?CheersPaul

Symptoms: Not fully ‘together’. A bit of light headedness. Can look slightly pale.

Doctor: Hi,Thank you for writing to Ask The Doctor.You had a simple case of dehydration. Even though you may not realise it while running, you lose around 1 litre of water. This caused you to feel dizzy and light-headed. In future, I recommend that you consume electrolytes during runs longer than 14 km. In short runs, keep a steady supply of water. After you are done running, have a good protein meal. The protein will promote recovery and help you be more fit for the next run.