Post ride recovery/head rushes

Bradders87

Alright guys, first post here. Now I've been quite a keen cyclist for years now, but never had the right kit...so my new purchase of an Orbea Aqua has had a lot of use. 80 miles had been my longest ride to date without any real issues.
Today I jumped on the bike at 9am to come hom from Bristol, 111 miles back to London in 8 hours. Great ride, hard in the heat, but I'm now getting head rushes that feel like I'm about to pass out every time I get off the sofa and I'm not sure what I'm lacking.
On the bike I took in 5l of water and a litre of gatorade. Stopped for lunch which had another half litre of relentless (got a Boots meal deal so I figured it was the best thing on the deal...). 4 pints of water since I got back and a reasonably large meal...what am I missing that's causing this?!

Cheers

SteveR_100Milers

It's only a momentary drop in BP when you get up from a resting position. I would have thought nothing to worry about as its quite common (I get it continually from taking prescription tamsulosin hydrochloride), but check it out with your GP if worried if its still there after a couple of days rest.

neeb

I often get this later in the day after unusually long endurance activities, whether cycling, hillwalking, whatever. Have done for years. You stand up too quickly and you feel light headed for about 5 seconds and need to stand still until the blood comes back to your head? It's called postural hypotension, it's just the body taking a while to adapt to the new posture. Nothing to worry about if it is obviously directly caused by the change in posture, only lasts for a few seconds and isn't accompanied by other symptoms. It must be something to do with the blood pooling in your legs due to the continued use of these muscles combined with lower blood pressure when you are relaxing.

If you are getting any other symptoms such as chest pains or palpitations see a doctor asap though.

unixnerd

I had that about 15 years ago for a year and it wasn't related to exercise (I didn't do any back then!). It just stopped happening all by itself, no idea why. Perhaps I changed something in my diet? Always seemed worse first thing in the morning.

neeb

Here's a good short article about it:

http://www.wisegeek.com/what-is-postura ... ension.htm

I think the take-home message is that although it can occasionally be a sign of other underlying problems, if it's clearly associated with post-exercise it's not something to worry about. These days I only get it if I do something really extreme that is way beyond my normal endurance limits, but if you are just starting out with longer rides you will be in that situation yourself.

Dr_Psychlist

I guess you lost a fair bit of salt and water in sweat - you replaced a lot of water but not much salt - that would drop your blood pressure and cause the symptoms you describe.