ExRx.net

It implies that the capacitance vessels (i.e. the veins) of the leg dilate and contain a larger share of the body's blood than they otherwise would. I just don't understand why this should happen any more after exercise than it should at any other time. In general, there are 2 mechanisms that work against this. First, the muscles of the legs have a pumping action--when the muscles contract, they squeeze the veins, and second, the veins of the legs have valves (other veins do, too, but not as many as in the legs) to help assure one-way flow of the blood. So when you are moving your legs, you are helping to pump blood back to the CNS. That's why they tell you to get up and walk around during long airline flights to help decrease the chance of blood clots in the legs.

I think that this is a greater issue while sitting in traffic for an hour than it is to leave the the fun run without some formal cool-down.

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Our greatest fear should not be of failure, but of succeeding at things in life that don't really matter.--Francis Chan

haha you nailed it doc. Sometimes some people's valves don't work correctly which could result in damaged veins like vericose veins and supposedly lead to those arrythmias because the blood doesn't return fast enough to the heart....

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"Opportunity does not knock, it presents itself when you beat down the door"

Kyle Chandler

Well, that is less likely to happen to someone who is exercising regularly. It usually occurs in overweight people, and usually late in life. And it would be happening all the time, not just after they ran a marathon. And that has little to do with possible arrhythmias. Just do whatever comes naturally after your exercise. No special procedure needed. You will cool down no matter what you do. Your text book is probably spot-on about absolutely everything else, but it's bogus on this.

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Our greatest fear should not be of failure, but of succeeding at things in life that don't really matter.--Francis Chan

When i first started running in my teens i would often feel a bit dizzy and woozy for a couple of minutes after a long jog. Not so severe that i thought i would pass out, but just the "head rush" similar to what one might feel when standing quickly after prolonged sitting. I mentioned it to a friend who was a more experienced runner. He told me you're supposed to walk around for awhile to cool down. That seemed to fix it. I still sometimes experience the sensation for a few seconds as i transition from a jogging pace to a walk (again, after a particularly intense run). As far as i know, i don't have any pathological blood pressure or anaemia stuff going on. And Jungledoc, if you read this, yes i HAVE performed a tilt table test on myself and it was negative :)

Hardly scientific but i just thought i'd throw that out there

I totally get that woozy sensation, too. It's like all the blood rushes to my muscles and there isn't enough left to flow through my brain. It's a weird feeling, isn't it? I actually went to the doctor for that a few years ago, worried there was something wrong. Apparently, there was nothing wrong with me. I was simply stopping too soon and not giving myself enough time to cool down.

This is the problem with the field of exercise science - the stuff they're teaching you is extremely outdated.

You should look for research outside of your books - I'm guessing they are at least a few years old, if not more - am I right?