Shivering and shaking during last interval


I did the Darwin workout this morning and had this new and quite unpleasant experience during the last interval.

first three intervals went fine, hard but manageable as expected for this type of workout. But two minutes into the fourth one, it seemed like hell on earth, I was actually shaking on the bike, arms, shoulders and neck were shivering and shaking uncontrollably towards the end and my heart rate went way up (+20 from previous intervals at the end). I finished on will power and I was fine shortly after the end of the hard effort

My question: did I just run out of fuel? Did Patrick Swayze’s Ghost visit me? have any of you had this type of experience, and if so, what did you attribute it to?

here is a link to it.

Thank you for any comments

(additional information: I have pushed myself very hard before, during races and group rides, crit races with 188 heart rate average, rides with 1.2 IF etc) but this came out of the blue with no warning on any of the three previous intervals that all felt pretty much the same. )

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Nice work fighting through and finishing that one :leg::biking_man::hammer:. It looks horrible! I think you were just at your limit for that last interval as your HR was at a steady increase and much higher than the previous intervals. I’ve never experienced the shivering, but definitely shaking at the end of a really hard interval.

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thank you for your comment, I also believe that I reached my limit, but had expected a warning shot beforehand. This getting older thing is really annoying.

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I have great friend I raced with and every time we did work at the end, he’d go so hard that he “went Bambi”, legs shaking so bad he couldn’t get them out of the pedals after the crit. Dude was in town, never used a smart trainer, hopped on mine and got the shakes. That’s all I have, no real advice other than “eat more high glycemic index foods during the ride”.

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Thank you, I shall indeed eat more in the future , That is always nice advice to hear !:grin:

One guy comes to mind who would do this at the end of races (a lot of times on the track) after taking a hard pull.

I’d second the eating suggestions- put something in the bottle

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I sometimes experience something like this when I am riding up to my limit. I am sure there is some physiological explanation related to thermoregulation.

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Since this is sudden and not normal I would schedule an appointment with your doctor right away. I’m no doctor, but hopefully, they can check your heart and make sure your fit for training.

I would tell them what’s going on and I bet they get you in super fast, maybe same day. I bet some real doctors on the forum would have better input than me, but I’d be better safe than sorry.

I’d also skip the training until you get this checked out. I’d love to hear what your doctor says too if you’re willing to share.


I’d send this suggestion. Cardiovascular oddities you don’t mess around with.

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Probably best for a doctor’s appointment to be sure.

My 2 cents…I’ll ask, were you pre-fueled/fueling/hydrating regularly? It’s something I experienced a looooong time ago when I played badminton competitively…did a few games back to back and ate practically nothing (I was young). I collapsed / blacked out and was told I shook a lot. My coach went ballistic.

Anyway, I use pee sticks to check my hydration now (was mentioned on a podcast a while back) and when it indicates a problem I think on how I feel and try to recognise it before letting it happen again. Lack of hydration and glucose can possibly affect your nervous system and that can affect everything if tired. If you feel cold then a warm-down is important…helps your blood flow…so maybe a longer warm down is needed. Even start thinking about or starting your nutrition…wait, where have I heard that before :grinning:

P.S. Drink because you’re thirsty is already too late.

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Hey Guys, Thank you all for your thoughts and inputs. After a good night’s sleep and revisiting the workout and my pre workout routine yesterday, I seems that I was indeed very low on fuel even before starting. And I believe that to be the cause of my muscle spasms.

However I will not downplay the possibility of other possible reasons as @Nate_Pearson mentioned.

I will monitor my next workout very carefully and for starters make absolutely sure that I have enough to eat and drink (indeed @andrewwylie ) beforehand and during and will then have a slightly more informed view.

Again, Thank you all for sharing your thoughts about this.

Have fun on the bikes !