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After a ride, usually about 15-30 minutes after a ride, I sometimes don't feel very good. I'll feel sleepy, lazy, lethargic or mentally foggy. It's not a physical tired. And often it doesn't take a great deal of riding to feel this way. For example, today I did about 15 miles and felt this way shortly afterwards.

I'm in pretty descent physical condition (I think), and I can ride 20-30 miles, at a steady 15-17 mph, without too much effort. But I'm really confused why I feel this way. I could/maybe should, see a doctor, but I thought I would check here first to see if anyone else experiences this.

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Are you consuming food after your rides? Such as something for recovery like chocolate milk or other protein/carb snack. Also, are you nourished before your rides? And then of course, are you staying hydrated? – user313 Apr 2 '12 at 15:25
What's your level of intensity? Are you on any particular diet (low-carb, vegetarian, etc.)? – Stephen Touset Apr 2 '12 at 15:31
Without knowing any more info than you provided, I'm guessing that it's a nutrition issue. You're riding at a pretty good clip, so this could easily be that your body is lacking nourishment. – user313 Apr 2 '12 at 15:53
One other question... It looks like you are doing fitness rides. Are you doing these on sequential days without rest days? Let us know your nutritional info and ride frequency. No one can give you a decent answer without that info. – user313 Apr 2 '12 at 19:27
up vote 9 down vote accepted

First off, can you explain a bit more about how you "don't feel very good"? Do you feel at all queasy? Do you feel especially weak?

Also, how often do you exercise so intensely, and how long have you been doing it?

And how long does this period of feeling unwell typically last?

Anyway, there are several possibilities (though most apply to rides longer than 15 miles):

-- Dehydration. Especially in warmer weather you need to drink plenty of water or other fluids. We've had arguments here as to how much, but it's not a bad idea to down a 21-oz bottle of water every two hours or so, as very rough guide -- more in hotter weather.

-- Low sodium. Again, in warmer weather it's quite possible for someone who exercises intensely to sweat off so much salt that the sodium levels in their body are not sufficient. (This effect can be doubled if the individual consumes an extremely low-sodium diet.) This results in fatigue and lethargy, and in extreme cases can be life-threatening, especially if mistaken for dehydration (which has similar symptoms) resulting in "water intoxication".

-- Low blood sugar. When you exercise you first consume the sugar in the blood stream, then the liver and muscles start converting stored glycogen to sugar. Several other mechanisms kick in as well. Especially in someone who has not trained extensively, this mechanism may not be able to supply the body with enough sugar and low blood sugar can result. In addition, some people suffer from what's known as "reactive hypoglycemia", where blood sugar drops paradoxically after a meal, after exercise, or at certain times of the day.

-- Ketosis. If blood sugar gets too low for too long the body begins to burn fat and protein directly. This results in the production of ketones which are released into the blood stream. This again results in an unwell feeling, including nausea, extreme fatigue, lethargy, and "brain fog". (Ketosis in particular will knock you on your butt for 2-3 days if it gets bad. Most other conditions listed here you can recover from in a few hours at most, if properly treated.)

-- Blood pressure fluctuations. Some people experience fairly extreme changes in blood pressure after exercising. This is usually short-lived, but can produce a wide variety of symptoms, from pounding headache to fatigue and fainting.

-- Neurotransmitter fluctuations. It's well known that exercise (especially intense exercise) causes the release of a number of neurochemicals. This is cause of the so-called "runner's high". And, of course, when one is "high", one will eventually "come down", and the result is a sort of "withdrawal" from the endorphins produced while exercising.

My guess is that you're experiencing a combination of slightly low blood sugar and the neurotransmitter "withdrawal", maybe combined with a touch of dehydration. Eating some sweet or starchy snack every 30-60 minutes while riding will help to level the blood sugar (and if it's a bit salty, all the better). Drink a cup or two of water with the snack.

And when you finish the intense part of the ride, take a leisurely spin around the block or whatever for 5-10 minutes to "cool down" -- not your temperature so much as your endorphins.

(You can, of course, experiment with different combinations of the above to try to narrow down what's the primary cause of your particular symptoms.)

But (though the doctor's checkup is never a bad idea) I wouldn't worry about it too much. After all, you've just participated in the second-best activity a man can experience, so a little let-down afterwards is to be expected.

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I'd go with the blood pressure and neurotransmitter hypotheses, too, and also the sugar might be involved (or the heat, or the cold), but of course we need more information. Ketosis would be unlikely, I think. And by the way, the best activity a man can experience, as everybody knows, is programming ;oP – heltonbiker Apr 2 '12 at 3:50
Still don't understand why so many cyclists are programmers and vice versa (speaking as both). – Stephen Touset Apr 2 '12 at 15:30
Wash, rinse, repeat. – Daniel R Hicks Apr 2 '12 at 15:43
@StephenTouset it might be even truer in a StackExchange-based bicycle-related web community. – heltonbiker Apr 2 '12 at 16:05

I usually feel a bit like this in the following riding conditions (one at a time or combined):

  • "In a rush";
  • In the cold;
  • In heavy/oppressive traffic;
  • With a bike that feels heavy;
  • While hungry (often);
  • Too soon after a meal (rarely);
  • During an overall mentally busy work day/week;

Soon after the ride, when you are home and finally relax, the body might react like this. It might be related to the sympathetic component of the autonomous nervous system, which regulates acute responses to environmental stress, exercise, alertness, and the general fight-or-flight response (just for information, the parasympathetic component regulates mostly the rest-and-digest response, when the body and mind are relaxed).

It is interesting to note that, most times, these are what would be called "non-discretionary bicycle rides", that is, I am not riding because I went out for the sole pleasure to ride a bike, but because I am going somewhere else to do something else, and the bike is just the transport. In these situations, since I am not necessarily "in the mood" to ride vigorously, it feels like the burden in the body is greater.

I think using a bike for transport might become a burden when you have some routines. Sometimes one might feel "burnt-out" for riding everyday, sometimes one feel full of energy for the same reason. It is very interesting...

I guess it might be considered normal to feel the way you describe, depending on a lot of conditions, PROVIDED that health issues are discarded.

I suppose you should really see a doctor just to make a regular checkup and describe your simptoms, to discard something that deserves greater attention. Then, you could consider some environmental factors (like, for examples, the ones I mentioned) and formulate your own hypotheses and strategies to cope with them.

I hope to have helped, and please send some feedback!

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I'd put a bit more weight to the hungry option. You should be eating within 30 minutes of the workout just to replace what you burned. – curtismchale Apr 6 '12 at 16:39

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