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Mechanism

I'm not bashing the idea of a cool down workout, but by what mechanism(s) would it help prevent the OP from passing out?
One likely cause of this is called orthostatic hypotension closely related to or the same as vasovagal syncope. Essentitally your exercising muscles are demanding lots of blood flow so all the capillaries are wide open. If you just stop without a cooldown "all" the blood pools in your legs resulting in low blood pressure and thus the faint. If you cool down and let things come more back to normal the effect is reduced.

That said I don't know of a well-conditioned endurance athlete who doesn't occasionally get a "head rush" when standing up after sitting for a while. What the OP never told us were the circumstances of the fainting spell. Some details would probably tell the story.
 

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In what area may I provide more details? I dismounted, walked around for 5 minutes or so, sat down for about 10 minutes, stood up, walked about 10 steps, and the next thing I remember I was down on the ground wondering where I was. Felt like hours had passed. Friend was there and told me I was out for about a minute. Whacked my head good when I hit the ground as I was out by then.
 

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.......... Fainting and the resultant prone position on the floor is the bodies' way of getting blood to the head. Saying the last thing you should do when you feel faint is to lay down is just wrong. If I would have laid down I would not have passed out, simple as that.
I've always been told that if you think you're going to faint... to get into the fainted postion [lay down]. It might not prevent passing out... but it mostly certainly will prevent the fall.
 

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One likely cause of this is called orthostatic hypotension closely related to or the same as vasovagal syncope. Essentitally your exercising muscles are demanding lots of blood flow so all the capillaries are wide open. If you just stop without a cooldown "all" the blood pools in your legs resulting in low blood pressure and thus the faint. If you cool down and let things come more back to normal the effect is reduced.

That said I don't know of a well-conditioned endurance athlete who doesn't occasionally get a "head rush" when standing up after sitting for a while. What the OP never told us were the circumstances of the fainting spell. Some details would probably tell the story.
2nd this enirely. The sooner after the effort, the more the effect. Even after a good cool down, and hours beyond, the leg muscles are still demanding, and open to accept more bloodflow. So, yes, the time/normalization during the cool down is helpful to avoid this when it may be most severe, and even during the rest of the day of the ride, a bit of caution when rising from sitting is not a bad idea.

I will have at least one or two head rushes the day of a ride, at times to the point that I need to stop to hold onto something, never quite to the point where I need to guide myself down safely, or worse, actually collapse. On days I don't ride, seldom, but occasional bouts.

So I agree that at least a few minutes of cooldown, proportional to the overall ride effort is important.
 

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I've always been told that if you think you're going to faint... to get into the fainted postion [lay down]. It might not prevent passing out... but it mostly certainly will prevent the fall.
Exactly. It gets the blood to your head which will (hopefully!) prevent fainting to begin with. Fainting sucks, and I've only done it once. Scared the crap out of me and I was very lucky that I fell flat on the floor between the lockers and the bench in the gym change room.

If I feel like that now, usually it's from standing up to quickly and I just sit back down until it passes then get up slowly.
 

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..... I was very lucky that I fell flat on the floor between the lockers and the bench in the gym change room.
A lot of damage can be done from a fall when passing out. A head... or even back injury can turn a non-issue faint into a lifetime problem.

I was also taught in a work related first aid training that the first step in even applying a band aid was to require the patient to sit down. A lot of people faint at the sight of their own blood. And where the injury may be very minor... the falling can cause real damage. It became an office policy that anyone even slightly injured was required to sit until the situation was evaluated.
 

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This.

A cardiologist once told me something similar. When in the middle of running/riding your leg muscles contract and relax. The contractions aid in the blood circulation. If you come to an immediate stop, your legs muscles are no longer contracting and the blood pools in your legs and makes your heart work very heart to keep it moving. This plays havoc with your blood pressure.



I think I was getting enough hydration, but that could have been it. I did drink a whole bunch of water after dismounting though. Is it common to have your eletrolyte balance thrown off as well? Two doctors, EKG tests, blood tests, and more revealed nothing.

One person told me the following - any truth in this?

They said this: Your legs act like a second heart when you are riding, helping circulate the blood. When you stop a long ride without a cool down, your blood vessels are dilated, which means your pressure drops, with high heat making it worse. So if you stand up quickly, your heart can't deal with the force required to keep your blood pressure up so you pass out.

I have no idea if that's true.
 

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Earlier in this thread I mentioned that I often experience dizziness after a ride, especially if I have not ridden in a week or so. I also mentioned that I had checked my blood pressure and blood sugar during the dizzy spell and both checked normal.

Well, yesterday with two rest days under my belt, I really pushed myself hard on a 50-mile ride (temp was 68 degrees) and soon after returning home I became so dizzy I had to sit down for awhile in order to feel normal again. I checked my blood pressure and it was quite low for me at 79/47 with a 114 heart rate. One hour later it was 82/57 and next morning prior to breakfast it was 110/69 which is usually about what my blood pressure runs.

Also checked blood sugar during the dizziness and it was 143. During the ride I consumed 24 ozs each of water and Accelerade and ate one Pro Bar (370 calories,
17g sugars, 18g fat, 70mg sodium, 48g carbs, 8g protein). About an hour before the ride I drank 24ozs of water and ate a peanut butter sandwich. Next morning prior to breakfast my suger was still high at 119. Shouldn't have been because the only things I ate for dinner the night before were a sandwich and a bowl of soup.
 

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....................... checked blood sugar during the dizziness and it was 143. During the ride I consumed 24 ozs each of water and Accelerade and ate one Pro Bar (370 calories,
17g sugars, 18g fat, 70mg sodium, 48g carbs, 8g protein). About an hour before the ride I drank 24ozs of water and ate a peanut butter sandwich. Next morning prior to breakfast my suger was still high at 119. Shouldn't have been because the only things I ate for dinner the night before were a sandwich and a bowl of soup.
Checked your blood sugar? Are you diabetic? Are things like Accelerade and Pro Bars the type of diet/foods recommended for diabetics?
 

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I passed out once while riding, started to go dark had just enough time to get off bike before crumpling up to the ground and fainting like a little girl. According to my docs at the time fainting right after strenuous exercise is pretty common if you just stop right away without a gradual cool down to bring pulse and BP levels down slowly

From the internet:

A common event in young adults, syncope is usually benign and only rarely requires more than simple reassurance. However, exercise-related syncope always requires investigation because it may be the only symptom that precedes a sudden cardiac death. Syncope that occurs during exercise tends to be more ominous than that occurring in the postexertional state. During the physical examination, the cardiovascular system should be evaluated carefully. An electrocardiogram is mandatory and requires close scrutiny, with further testing ordered as indicated. The investigation of syncope should specifically exclude known pathologic diagnoses before a complete return to activity is permitted. In cases where a diagnosis is not clearly established, consultation or referral may be warranted.

Syncope is a common event in which there is a transient loss of consciousness and postural tone. Although syncope is generally a benign event in young adults (less than 35 years of age) and, in many cases, never reaches the attention of a physician, exercise-related syncope can signal sudden death.
So yeah basically just listen to whatever your doctor told you
 

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No, I am not diabetic.
Maybe it's time that you consult a doctor and do a glucose tolerance test, and have your a1c checked. I am a diabetic, and if my glucose was 143 mg/dl after a 50 mile ride, it would be way out of the ordinary. I'm not familiar with Accelerade, and it may well be loaded with sugar, which could explain the high reading. The Pro Bar, with 48 mg of carbs, shouldn't have spiked you to that extent. That's about what I would consume during a 50 mile ride. I would also eat about 25 gms before the ride. Fat can also elevate glucose. The 18 gms of fat might have contributed to the high reading.

A number of factors can account for it, though. Stress, infections, many things can result in elevated glucose.

Also curious as to why you have a test kit. Those test strips aren't cheap, unless they're covered by your health insurance. If you bought a kit and they included a sampling of say 10 strips with it, those strips don't have an indefinite life. Old strips won't give you an accurate test reading.
 

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Maybe it's time that you consult a doctor and do a glucose tolerance test, and have your a1c checked. I am a diabetic, and if my glucose was 143 mg/dl after a 50 mile ride, it would be way out of the ordinary. I'm not familiar with Accelerade, and it may well be loaded with sugar, which could explain the high reading. The Pro Bar, with 48 mg of carbs, shouldn't have spiked you to that extent. That's about what I would consume during a 50 mile ride. I would also eat about 25 gms before the ride. Fat can also elevate glucose. The 18 gms of fat might have contributed to the high reading.

A number of factors can account for it, though. Stress, infections, many things can result in elevated glucose.

Also curious as to why you have a test kit. Those test strips aren't cheap, unless they're covered by your health insurance. If you bought a kit and they included a sampling of say 10 strips with it, those strips don't have an indefinite life. Old strips won't give you an accurate test reading.
I appreciate your concern and your comments.

During the past year or so I have I sometimes felt more fatigued after a ride than at other times and bought the test kit just to see if anything unusual was going on with my my blood sugar. The test strips are about a year old.

My sugar is usually well below 100 after a long ride. Same goes for before breakfast each morning. Don't know what caused the spike after that particular ride but it could have been the Pro Bar which I had never tried before. I usually drink 24 Ozs of Accelerade and eat a Clif Bar, Power Bar or peanut butter sandwich during a 50-mile ride and blood sugar looks okay when I get home. You are likely onto something with your comment on fat. Fat content of the Clif Bar (1g) and Power Bar (3g) are considerably lower than the 18g of the Pro Bar.

I am 72 so perhaps age is finally beginning to catch up with me,

Edit: Forgot to mention that I am recovering from a prostate infection and as you say, that may also have contributed to the high reading.
 

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I usually stick to Powerade Zero for my sports drink. I think it only has one gram or so of sugar. It's mostly water, electrolytes, artificial flavoring. I think it might have sorbitol as a sweetener.

I usually choose Cliff Bars and Power Bars too, because of the low fat content.
 

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Don't take this wrong.... but a fifty mile ride... does it really require dietary supplements? I am an older guy myself at about 23 percent body fat (BMI of 24). I used to take along gels and spike my water... but decided it wasn't needed. Or in my case even desirable.

A fifty mile ride at ether end of the fitness spectrum would be a two hour to a four (lets say 5) hour ride. I know full well my body has more than enough available fat reserves to get me through the five hour ride (even if I don't stop for lunch). And the short fast ride (and I am NOT that fast) still would not exhaust available fats and blood sugar.

Worst case... I could likely stop for a coffee and give my body the necessary time to metabolize a bit more body fat for energy. Or stop for an emergency ice cream, candy bar, or my favorite... a vitamin water.

I understand the pros with such low body fat levels needing regular food intake. Because they just don't want to waste cycling energy with extra body fat weight. But the average person carries plenty enough fat around with them. I could be completely wrong! This is as much a question as it is my opinion.
 

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It's not a big deal for most people to burn fats instead of carbs (although they're not metabolized into glucose as efficiently). However, for insulin-dependent diabetics (type 1 and some type 2) ketoacidosis can be a serious matter.
 

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.....for insulin-dependent diabetics (type 1 and some type 2) ketoacidosis can be a serious matter.
Yeah... I sorta knew that. And I didn't mean to leave out any special-diet/needs cyclists. I just don't know enough about diabetic needs to ofter much of an opinion. Sorry.

I just think that the pushing of gels, special bars, treats, powers, and drinks is often a disservice to the typical cyclist.
 

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I've read that bananas are just as good for electrolyte replacement (especially potassium) as most sports drinks. Unfortunately for me, they're one of the fruits that send my glucose levels into orbit, so I'll drink Powerade Zero on a long ride, alternating pulls from that bottle with water. It's one of the curious things about diabetics, that different foods affect individuals differently. My buddy can't eat brown rice, but oranges and bananas are fine for him. I'm the exact opposite.
 

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I've read that bananas are just as good for electrolyte replacement (especially potassium) as most sports drinks. Unfortunately for me, they're one of the fruits that send my glucose levels into orbit, so I'll drink Powerade Zero on a long ride, alternating pulls from that bottle with water. It's one of the curious things about diabetics, that different foods affect individuals differently. My buddy can't eat brown rice, but oranges and bananas are fine for him. I'm the exact opposite.
Back in the summer I was chatting with a cyclist at a rest stop during a long charity ride who mentoned that he is diabetic. He said that Diet Coke elevates his glucose levels. I was quite surprised to hear that since it contains an artificial sweetner. Have you experienced the same?
 
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