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Drowsiness and elevated body temperature an hour after exercise?

It went like this:

I'm male, 25. I went to jogging at 17.00 to a forest area where trees provide a lot of shade, temperature was 29 °C with a relative humidity of 57% (Eastern-EU). I run twice a week.
During the run I wasn't tired or exhausted at all, it was convenient. After that I always sweat profusely though.
I went home (air conditioned), drank cold water and had a warmish shower.

A half an hour after I sat down though I got drowsy / sleepy and felt a bit cold (just enough that a blanket felt good).
Heart rate was 82 bpm, higher than usual. I had a nap and all is fine.

I read about heat exhaustion and heat stroke but those happen during the exercise (if overdone), not an hour after in an air conditioned room and those symptoms are far more severe than what I had.

My question is, why do I get a fever and drowsiness only an hour after the exercise but feel completely fine and barely tired (though sweating a lot) during and right after it? I drink a lot of water before and after.
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Avatar universal
Does this happen often, or is this the only time it happened?  Because life is never the same all the time.  It sounds like you were just a bit tired.
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I happens often when I go for a run. I'm unsure how can I get an elevated temperature in a cold room if I was completely fin during and after the run.
Your temperature should go up every time you exercise, then go back down again to normal.  That's one of the purposes of exercise, to get your heart pumping and your blood flowing.  However, a more interesting question is, why are you taking your temperature so often?  Many people who test their bodily functions a lot when there are no known health problems have an anxiety problem.  Not necessarily a crippling one, but most people don't measure their temperatures or blood pressure or the like but some do it a lot.  A temporarily elevated temperature isn't a fever.  As for the rest, I don't know.  You could be eating insufficient nutrients.  You could be drinking insufficient water.  You could be taking in insufficient electrolytes.  You could be getting insufficient quality sleep.  You could just be getting really relaxed after your run and have more time because of covid to drowse off.  Who knows?  If it's of enough concern to you, get a thorough exam from your doc.  To me, it sounds pretty normal for someone who seems to have a lot of free time, because if you were busy at school or working you wouldn't have time to drowse off and take a nap.  Maybe you're bored.  It's going around with covid around.
As far as feeling cold after a run, even a hot run, this is very common.  I recommend googling "post run shivers".  I usually get cold about 20 minutes after getting home in the air conditioning and eating something before showering, in my case it obviously sitting around in sweaty clothes that causes it.  But, some people experience exactly what you described.  It might have to with when you are running, your capillaries in your skin dilate to  bring more blood to the skin to help cool you down (whether it is hot or cold outside, this happens).  After you are done running, your body might still be trying to send blood to the skin to be cooled by the environment, and it takes some time for it to switch back to normal, even though you are no longer running.

Making sure you rehydrate and have enough electrolytes is important, but sometimes, this just takes a little time to switch back.
Avatar universal
How do you know your body temperature was elevated?  Because you felt cold in an air conditioned room when you were not running?  Or did you actually measure your temperature.

As someone who runs frequently, what you are describing - an elevated heart rate hours after finishing a run, is more comparable to when I run very hard efforts, for me that would be an hour of 1 minute "fast" 1 minute "slow" intervals, where my heart rate is elevated to the mid 160s when most of my runs it is in the 130s and 140s (what the heart rate is doesn't matter, what matters is I'm pushing harder than normal).  Both my heart rate and blood pressure take hours to come back down.  I don't do this type of workout that often, for running I need both lots of long, easy paced runs and every so often a faster paced workout.

What is going on here?  In my case, this is probably "oxygen debt".  When I do faster paced workouts, my muscles aren't getting oxygen fast enough and my body starts producing energy by an anaerobic pathway, which produces lactic acid.  This lactic acid must then be cleared from the muscles after the run, which requires more oxygen that what would normally be used in this clearing process.  You might find yourself breathing heavier, and having a higher heart rate for some time period after the run.  According to one website, it should take 1 hour to clear lactic acid with active cool down exercise, or 2 hours or more if you don't warm down with gentle exercise.

Signs of heat stroke or heat exhaustion while running (for me):  I start to get dizzy.  I stop sweating.  My heart rate spikes and is at a much higher rate than the pace I'm running at.  If those things happen, usually on very hot days (we're talking full sun, mid to high 80s, usually 29 deg C or higher), I will call for someone to come pick me up.  I usually bring water (and electrolytes if it is hot), and can frequently last for 2 hours or more in this type of heat, but sometimes I can't.  Heat exhaustion is something you would probably notice was going on at the time, and hopefully take seriously.

Why don't you feel the oxygen debt when it is happening?  Well if you are anything like me, you enjoy running and the rush of adrenaline while running will cause you not to feel pain that you might otherwise feel.  It also constricts blood vessels to some parts of your body and directs blood flow to your large muscle groups to aid the flight or fight response.  Endorphins generated running can also help you ignore and pain or problems your body might be feeling at the time.

So... do you feel this way on every run?  And if so, are you running every run at the same pace, where it would be difficult to hold a conversation or comfortably maintain for hours at a time?   I don't think experiencing "oxygen debt" is a bad thing after a particularly tough workout.  But, if this is something you are encountering after every run, I recommend reading about different types of training. Many training suggest doing the majority (80%) of your runs at an easy pace to build up endurance, and only 20% or less at a faster pace where you'd be generating lactic acid.

As for heat exhaustion tips --- I ran a marathon last year in 85 deg weather (29 deg C and up), while apparently anemic although I didn't know it at the time.  As soon as I started feeling dizzy (about 15.5 miles in), I switched to a run-walk strategy.  I drank lots of water and electrolytes.  I felt fine after finishing, because I was keeping my heart rate in a lower range.  (I felt much better after that marathon than the previous one which was in the 50s which is around 10 deg C.  The hotter it is outside, the slower you need to run to maintain a lower heart rate.  It doesn't mean you can't run fast in the heat, I just don't recommend doing that every day.

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Avatar universal
It may be because you start exercising after some time and you got fat and your body does not like this type of routine that's why it's showing some affects it is positive but if you are regular then if it does not go too high and you catch up after some time than it is not a problem but if unbearable than you should avoid doing too much cardio or take your body fitness slowly toward your aims love the process it's going to take some time you will get it some day .
have a nice day spread peace.
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