Today I experienced one of those weird occurrences that have baffled me ever since I seriously got into fitness – call it the Bermuda Triangle of Exercise, if you will. Just like Amelia Earhart – but less heroic and revolutionary and without the rubber helmet (just what exactly was that supposed to protect you from anyhow?) – today I awoke to a morning just like every other morning, not knowing that by the end of the day I’d be in the grip of a natural phenomenon that science is at a loss to describe. CrossFitters, with their characteristic understatement, have taken to calling what happened to me today “a metabolic reaction.”

So there I was, dreaming blissfully of gym underwear that won’t wedgify, when I awoke to a toddler shoving a balloon in my lips and commanding me to “fix it.” The balloon, like all toys in their natural state at my house, was broken. This is awesome in two respects: a) every mother knows that popped balloons are Public Enemy Number 1 as they are the worst choking hazard known to humankind – not even the best EMT can dislodge the nefarious party good from a tiny windpipe, thereby requiring me to forcibly seize said balloon pieces, leading to b) an argument with a tiny person whose reasoning skills can best be described as “on the fritz.” It was an inauspicious start to my day. Needless to say, I missed out on my first a.m. meditation.

The gym started out mellow with Gym Buddy Allison and I running laps and catching up on our weekends. We then moved on to the Monkey Bar Gym workout for the day and amused all the men on the weight floor by attempting plyo pushups alternated with “gorilla ups” – a plyo pull-up with a chest slap (hence the gorilla) at the top. As we were finishing up, we noticed Gym Buddy Krista in one of the studios. At first we were confused as to why she wasn’t working out with us and then I realized with a bolt of panic that I had signed all the Gym Buddies up for a kettlebell tutorial immediately followed by a Pilates Reformer class. Today. Allison and I ran in sweaty and disoriented.

So after getting a good burn from the MBG and sweating buckets in the kettlebell class, we started on the Reformer already a bit shaky. I’m not used to an hour and a half of straight no-rest strength training and so by the end was a gooey quivering mess of flesh. All good workouts – don’t get me wrong, I enjoyed them! – but I was hammered. By the time I got home I knew I was going to have a “metabolic reaction.”

Knowing what was coming, I did my best to prepare. I fed the kids lunch, settled the baby for a nap and the preschooler with a movie and tried to get some work done before it hit. And hit it did. The first time I had a MR, I ended up passed out on the wood kitchen floor, asleep for a solid 30 minutes while my children ran circles around me. And when I say asleep, I don’t mean cat-napping. I mean o-u-t. Tornado sirens would not wake me. So today as soon as I started to feel tingly and woozy, I ran upstairs to my bed. I didn’t wake up until the first grader got home off the bus. And then I continued to feel unwell – spacey, tingly, fragile and with a ferocious and insatiable craving for simple sugary carbs – for the rest of the evening. I’d be in bed again now except I still have to grade the cursed SATs tonight.

This isn’t the first time I’ve had a MR. Normally it happens when I try a new and particularly challenging workout. I’m not alone in this. Gym Buddy Allison has experienced a MR and it’s also well documented on the CrossFit forums. But I haven’t been able to predict exactly what circumstances will trigger a MR. What causes it? How do I prevent it? And what is it exactly? It’s not just a function of too much exercise – I’ve gone hours longer than what I did today with no ill effects. It’s also not like “bonking” in an endurance race (I’ve done that too and while it feels awful, it’s awful in an entirely different way.)

Does anyone else know what I’m talking about? Anyone else ever have a metabolic reaction to exercise? What did you do? Anybody figured out a way to prevent them?

I’d really like to get to figure it out because I really can’t be doing this when I have a houseful of little kids with a predilection for playing with popped balloons.

40 Comments

  1. Hypoglycemia? I have been pretty tired from workouts, and I have been too dehydrated from the sauma. But not M.R. what ever that is. Glad you are OK. Isn’t there something about when kids are crabby they need either food or sleep or both?

  2. Yup, sounds like your blood sugar pretty much tanked. If you start feeling like that, eat something already! I find that during intense workouts, I HAVE to something other than water…Gatorade, juice, a sugary icee (healthy!) to keep me from hitting the blood sugar wall.

  3. Low blood sugar? Really?? But I had a HUGE lunch when I got home! Wouldn’t that have fixed it so that I wouldn’t have crashed later on in the day?

  4. The Wettstein Family

    You probably needed the sugar during your workout. If I know I’m going to have a tough workout, I take Propel or Gatorade with me or I’ll pass out or puke. I don’t know why it happens to me (especially when I do a lot of floor-to-standing and jumping movements), but the gatorade keeps that from happening. I hope you find out what works! That’s scary!

  5. Hey, could you maybe explain a MR more? I think I may have had something like that last week after a completely normal 10 mile run(it was just a tad faster than normal and the day after a moderately hard tempo run). Less than 3 hrs after I completed the run I could barely walk up stairs, lift my arms, or turn over in bed due to soreness and my blood pressure was waked, I could barely stand up without it crashing through the floor, I was also disoriented and nearly called 911 to be taken to a hospital because I was so scared and confused as to what was going on. (I have never been sore like that as a result of a workout and I know the workouts I did in the past 2 days could not have caused it because they never had before, however I have never done a speed work out the day before a long run). I had eaten pretty much normally for me, etc. 24 hours after it all started I was nearly 100% better, but I was incapacitated for those 24hrs practically.
    All that to say is that anything like an MR? I am so curious as to what happened to me that day.
    Sorry for the long comment, just very curious about your thoughts.

  6. Heather McD (Heather Eats Almond Butter)

    I’ve never experienced anything like this, but I agree with the Wettstein Family – maybe keep a carb/protein snack in your gym bag when workouts become more intense or are longer in duration than plan…then make sure to eat right after. Just reading your workout today made me bonk. Night!

  7. Hypoglycemia is my first thought too.
    But Im not dr (and dont play one on TV) nor am I any help.

    never happened to me!

  8. Def low blood sugar. Do you drink anything like gatorade while you’re working out? Or eat some sports beans or something? That should alleviate the problem. Drink/eat every 20 minutes or so during a really high intenstiy workout like that, and injest something as soon as you can when you’re done working out.

    If you wait too long to eat lunch after you work out, you’ll still crash in the afternoon due to radically quick changes in horomone levels. You know, the insulin spike and crash? It’s a vicious cycle. I spend afternoons after my long run sleeping on the couch pretty much all day.

  9. Charlotte,

    What you describe does not sound so bad to me. I have had similar experiences; they seem to occur when I combine hard physical work with hard mental work. I usually enjoy getting some good, uninterruptable sleep.

  10. Perhaps your glycogen stores are almost used up, combined with some form of hypoglycemia? Like everyone else here (except Dr. J :)), I’m no doctor, but it seems like I can tell when my glycogen stores are high (after carbo loading), perhaps what you’re experiencing is a depletion (or at least a reduction) in your glycogen. ??? So sorry this happened to you!

  11. I’m not a doctor, but I don’t think you would have crashed like that from hypoglycemia after eating a good meal. My guess would be a mild or borderline rhabdomyolysis, which can be caused by excessive exercise. Sort of a cascade effect of muscle tissue being damaged; “metabolic reaction” isn’t a bad name for it. In a healthy person, you re-stabilize after some fluid, nutrition, and rest. If it happens too often, too close together or in a health-compromised person, it can get serious and lead to kidney damage. I’d recommend sticking to light yoga for a few days after one of these episodes. But again, I’m not a doctor, I think it’s just common sense.

  12. I was going to say that this is similar to a diabetic low blood sugar reaction. Looks like just about everyone responding is saying the same.

  13. I have the same problem– it’s so spiratic that it was hard for me to initally figure out why it was happening. It happens to my husband too, so we finally decided it is due to what we did the day before we did that specific work out– We determined that the day before we did not drink enough water, get enough sleep, food, etc. We found a way to combat it by drinking power edge energy drink prior to working out. Not an exact miracle elixer, but it does make a difference.

    I don’t buy the blood sugar issue since it happens to you, me and my husband, among others. If you figure out what it truly is, I’d love to know!

  14. Like everyone else said, it’s likely hypoglycemia. After about 45 minutes to an hour of moderate to high activity (and less for high activity) you’ll have used up all your glycogen stores, and need to replenish them with simple sugars. After the first hour, you’ll need to keep eating sugars about every 30 minutes.

    You’ll still feel drained, but this will make a world of difference.

    (Aside from my own experience doing marathons and playing tackle football, I’m also a coach and this some basic sports nutrition information that I’ve learned from various coaching clinics.)

  15. This exact thing has happened to me. I too was curled up on the kitchen floor and I was winded after going from the basement to the second floor. It basically took all day for me to recover.

    I don’t know if it is hypoglycemia. Usually if my blood sugar drops I can recover. MR (I love that term, by the way) sacked me for the entire day.

    I would love to hear more on this topic. Thanks!

  16. It could be hypoglycemia. Depending on some other symptoms, you could have had mild rhabdomyolysis.

    If you had muscle pain and/or swelling 0-24 hours after working out, or dark urine, it may have been the latter.

  17. Wait, so is “metabolic reaction” code word for “physically exhausted”? That is A LOT of working out — no wonder your body konked out on the kitchen floor. You was tie-tie.

  18. Well, being a slacker myself my first suspicion would be that doing what sounds like 3 full workouts in a row (mbg, kettlebell, and reformer) you might be getting too much exercise?

    But it sounds like for you that’s kinda normal. Personally, I’d either cut back a bit or check in with a doctor.

  19. I just can’t imagine working out that hard 🙂

  20. I wish I had some more useful comment to make than “Yikes!”

    Sending positive thoughts instead, in the hope that that will make up for my lack of helpful suggestions.

  21. Not to make light of this (because it’s really scary!), but this could be a perfect excuse to eat jelly beans. At least, the sports beans that come in the form of a jelly bean.
    Or at least, as others have said, bring some gatorade with you and drink during your workouts.

  22. make sure you stay hydrated and eat every few hours! Great site!

  23. I’m inclined to agree with hypoglycemia of some sort.

    And I have been told many times that I’m a mean mommy (not by my children) because I won’t allow them to have balloons. I hate balloons. They’re dangerous, they pop (and startle me), they float away and leave children crying. No balloons.

    I know you’re mostly vegetarian – any chance you are anemic? Anemia can cause sudden extreme fatigue, I believe.

  24. After a long run in cold weather, usually about 2-3 hours after, I have something like this happen to me. You're right, it is completely different than bonking during a run/ride. I switch off for 30 minutes or so. Dead to the world asleep, preferably curled up with a really warm sweater or blanket.

    I make sure I'm hydrated during and after workout. I eat the appropriate combo of protein & carbs. Change out of cold wet clothing and shower. Those things might delay the forced nap, but nothing stops it from happening. When I wake up, I'm back to normal.

    Fortunately, my children are older, and the teenager is sensible (& bossy) enough to prevent dangerous behavior in the younger two.

    They find it rather funny, and declare it automatic video game time, because they know I'm OUT.

  25. Holy crap! I used to have that ALL THE TIME when I danced! I had no idea there was a term for it!

    As someone who is ALSO hypoglycemic, it wasn’t the same for me: there was definitely a difference between what you’re describing and when my blood sugar tanked. That said, low blood sugar definitely made it worse. A LOT worse.

    I finally was able to mitigate it (though it never went away completely) by drinking a couple of glasses of orange juice right after a workout (for the blood sugar) and by not getting too hot DURING the workout. If I once overheated, it was all over but the crying, and all the OJ in the world wouldn’t help.

    So, that’s my two cents: keep your blood sugar up (and think simple carbs; don’t be messing around with whole grains) and don’t get too hot. If I did that, I could dance all day (7-8 hours) and I’d be ok. I’d still sleep like a ROCK at night, but I didn’t crash before then.

  26. Every Gym's Nightmare

    i can bend space and time after a good run. that’s the same thing, right?

    Kelly Turner
    http://www.everygymsnightmare.com

  27. Not quite sure what exactly this metabolic reaction is. Do you mean physically exhausted like what Leslie said?

    Have had instances where I’ve just CRASHED, usually when I was in my 2nd month straight of boot camp. I assume that it’s a sign of having worked your body past its limit and it simply can’t compensate no matter how much you fuel it so it needs sleep to recuperate.

    Am curious!

  28. I know everyone is saying hypoglycemia, but I’ve had the same reaction from a probably less common condition. I had low iron (not a level to make me anemic) until I started supplementing. When I would do a super hard workout, I would get so worn out that I felt almost like I was going to pass out..total fatigue. I would eat thinking I was just low on sugar, etc., but that had nothing to do with it! Just another idea.

  29. i think it’s both the low sugar thing AND the intensity of your workouts. If I’m going to do any sort of physical activity more than about 80 minutes, I HAVE to bring gatorade at the minimum. Sometimes I’ll have a protein bar to take nibbles of or those nasty power gels/gummies for runners.
    I’ve had this happen to me–but only after a workout that seemed to hit over my intensity threshold. I think you can build up your so called threshold—but what you did the other day was or probably should always be over the mark. The first time it happened for me was after a “long” run when I trained for my first marathon. Somewhere around 15 miles, my body demanded to know why the heck I was still running.
    Anyway….I’ve been very active since an early age. This has happened to me–but less and less as time passes since I seem to have gotten the knack of planning ahead.

    Bottom line–Even if you had packed the Gatorade or a bar between those classes–there probably would have been some sort of crashing.

  30. after reading your post and all of your comments….i’m now SURE i have no idea.

  31. I think “Never Say Diet” nailed it: MR is a euphemism for “totally exhausted.”

    This has happened to me a few times. It seems to be caused by a combo of high total volume of work, plus an emphasis on CNS (central nervous system) type of workout.

    Actually, I like the sensation. To work myself to the point of practically falling asleep on my feet, and then to pass-out in a deep sleep. I’m usually ravenous when I wake up, then after a big meal I feel like a million bucks. I wish I had the time to do it more often!

  32. This happened to me, and it’s NOT low blood sugar! Thanks for naming it; I’ve been describing it as feeling like Vicodin. Meaning it’s a good exhausted feeling with a calm euphoria instead of the jangling, shaky, crabby exhaustion of low blood sugar. I think.

  33. I’ve had the same thing happen to me and it’s definitely not blood sugar, though low blood sugar probably doesn’t help. I had them more often when I was at a really low weight for me. Once I gained a couple of pounds, they seemed to happen more often, but they’re still not totally gone.

    Honestly, I think it’s just a combination of mental and physical fatigue. Exercise releases a whole cocktail of stuff like serotonin, dopamine, norepinephrine, adrenaline and endorphins, and that’s just in your brain. It might be your glycogen getting depleted, or maybe it’s the effect of lots of serotonin over time, which has a proven but totally unrelated slew of potentially fatal consequences called serotonin syndrome. Extended periods of stress do weird things to your body, and something about them trips some switch that says ‘oh please god feed me feed me ‘ instead of ‘get some rest, drink water, take a break.’

    It’s almost like overtraining, but over a really short period of time as opposed to weeks and weeks.

    Hell, what do I know. I’m just guessing. It’s not the exact mechanism that matters, it’s the getting yourself into bed that counts.

  34. Another thought…when you’re working out that hard, make sure you’re getting enough fluids, but also make sure you’re getting electrolytes. At some point, you sweat out so much sodium that drinking a ton of water to hydrate is just not that good for you. The cells get unbalanced…

  35. Deb (Smoothie Girl Eats Too)

    OMGOMGOMG I had that exact thing happen to me once. I had my hubs drop me off in the desert at 700 ft above sea level and I rode my bike up to the mountains at 4500 ft and about 29 miles. I was well-fed, well-hydrated and it wasn't a difficult ride at all! I'd done far harder.

    When I got back after about 30 minutes I just felt UNWELL. I didn't yack or sleep. I just felt shaky and like crap. I figured it was the altitude change and it dashed my hopes of riding Haleakala on Maui.

    Did you ever figure out what it was scientifically?

  36. I almost always have to sleep after any run longer than 6 miles or I spend the rest of the day sick and shaky and cranky and nauseated and exhausted. Of course, when I was training for my half marathon and 6 became a short run, I could *sometimes* get by without a nap afterwards, but that sort of reaction was a weekly thing for me. I just think that my body recovers a more efficiently when I am asleep and that it needs a break.

  37. By 'MR' you mean "I am tired therefore I nap". I am 46 year old who works a 7 on and 7 off 11 hour night shift. My routine has me working out 1.5 hours before a night shift. Having lost and kept off 65-70 lbs the routine is important. Gte used to it.

  38. definitely low blood sugar and borderline some kind of “bonking” whether you think it or not. you needed food WAY sooner than you let your body go. remember, 15-30 min after a workout, EAT or drink something with substance.

  39. Pingback:Why Am I So Tired After My Deep-Tissue Massage? [The theory behind metabolic reactions, DOMS, and PMSM]

  40. So I just Googled “I get tired after working out and fall asleep”. Got your story about sleeping after a massage and then saw the link to this. This is EXACTLY what happens to me. I used to drink a water bottle with Kellogs protein powder added to it and go for a 2 hr. walk. (was getting ready for a beauty pageant) When I got home, I would eat a protein bar and PASS OUT asleep. Like you said nothing could wake me. I call it the coma sleep. I don’t work out that hard anymore but occasionally the pass out happens or I need an afternoon nap. Last night I was asleep around 10PM and the alarm went off at 6AM. Full 8hrs. At 7AM, having had no food and only a few sips of water, I walked on the treadmill for 54 min. and went 3.19 miles. I felt great! I got my cup of coffee sat down in a chair, had 5-6 sips and I felt the severe drowsiness hit. I put a pillow under my neck, turned over and let myself sleep that deep sleep. I always feel great afterward but I hate losing an hour of my day. I guess if I trudged through a day being tired, I would get less done anyway and I do feel amazing after getting the sleep. I often wondered if it was likes diabetic low-sugar thing. I’m glad I thought to check and see “I’m not the only one!” I will now look up MR. Thanks for the story 🙂

    I have found my “happy” spot with a good schedule: in bed 9-9:30PM to be asleep by 10, up at 6AM and exercise first thing. I truly feel “happy” when I am on this routine like when I used to take Paxil. (no drugs needed now) I am extremely productive and if I don’t have the pass out, I usually need a nap and set the alarm for 1hr. but I get more done than when I’m not on the schedule. I eat mostly clean and healthy, don’t smoke and drink very occasionally. Life is good 🙂