The Bonk, induced by water?

Chuffmeister
Chuffmeister Posts: 5
Hi

I'm new here, so hello!

I got back into cycling later last year and have been cycling a regular 35 mile round trip to work from Deal to Folkestone in the UK 2/3 times per week. However, yesterday really threw me and I bonked massively on my return trip, which was totally unexpected. I've always pushed and challenged myself and never experienced anything like this before. However, the symptoms began immediately after drinking water, which is something I don't normally do whilst I'm cycling. My jaunts are normally around 90-180 mins and I have always re-hydrated on my return. Having done a bit of reading today, it would appear that drinking can dilute your blood sugar. Has anybody else experienced this? I guess I should have something isotonic.

As for the hypoglycaemia, it was awful and in hindsight quite worrying and very dangerous. Its quite hilly my ride, but I have never had an issue with it. I have done the trip all in one go as a training exercise without problems or stopping to replenish. Yesterday's return trip got the better of me for some reason.

Yesterday, I did two things differently. I only did a half day at work in the afternoon (cycled 17.5 miles in) and I drank partway through my journey home as I decided to use my new cycling bottle! Looking back, I only had a bowl of cereal for breakfast at approximately 0745 and two slices of toast at about 11:00. I cycled to work in record time which was good (1:10). I didnt each much whilst at work between 1300 and 1745 other than a few mini sausage roles.

The cycle back was going fine. There are two large hills (Folkestone Hill and Castle Hill in Dover). The rest is a good slight gradient downwards and with a good pedal, you can push along between 30-35mph. It was after the second hill, followed by gradual 1.5km gradient that I had a drink whilst cycling and began to crave sugar. This was the start of the bonk and on the easy straight and gradual decent with only about 6 miles to go to my destination!

I initially began to feel a little out of breath, almost a bit tight chested as if I couldn’t quite ‘hook’ each breath. The temperature seemed to drop too and all of a sudden I felt the cold. I continued to cycle, but noticed slight blochiness in my eyesight. Initially, I put this down to being sweat on my glasses, but as I progressed another mile, I developed tunnel vision. I then became disorientated. Pushing on, I almost missed my turning down my usual cycle path and became less aware of my surroundings. The usual landmarks of my ride seemed to appear much faster than I expected and I was less stable. I again approached the usual coastal road and missed my turning for the cycle path. The next thing I recall was passing the next landmark and almost missing my driveway. I fely utterly exhausted. Getting the bike up the few front steps was a major obstacle. Eventually, back in my home, I headed for the kitchen, grabbed the first sugary thing I laid my eyes on and then collapsed onto the floor.

What ensued was dizzyness, shortage of breath, extreme tiredness, blotchy vision, pins and needles, palpatations, ringing in my ears, cramping in my feet and total fatigue. I cold barely raise myself for a drink or raise my arms. Fortunately, my girlfriend was present and proceed to hydrate me and feed me chocolate bars and half a sandwich (every cloud has a silver lining!!!). After 30 mins, I tried to stand. Unable to do so, I resorted to crawling into the bathroom, before suffering from more pins and needles and dizzyness. I felt as if I was going to black out. I lay on the floor with my feet elevated for another 20 minutes before getting into a hot bath and then shaking uncontrollably. More drink and toast followed until I eventually warmed up. I had begun to recover, but just wanted to drift off from that point. I had just experienced ‘the bonk’.

It became more worrying when I began to think about my journey back. I am unable to recall large chunks of the last few miles and missing my turnings etc, goes to show what state I was in mentally and just how unaware I was on my surroundings and immediate envirinment. I remain a little confused as to why I bonked, especially on a relitively average journey that I have done many times before. Was it the lack of carbs or perhaps it was induced by drinking part way through? However, I guess it goes to demonstrate that you never know when it is going to get you. Certainly, I will ensure that I eat before and after my return journey from now on and carry some sugary snacks/ boiled sweets that I can munch on should I ever be unfortunate enough to experience this again.

One thing is for sure, I will recognise the symptoms in the future and do my utmost to avoid this vet unpleasant experience again!

All feedback welcome!

Comments

  • webboo
    webboo Posts: 6,087
    That doesn't sound like any bonk I have had or witnessed in friends. I think I would be seeking a medical opinion after something like that.
    It sounds more like a case of hypothermia.
  • TLDR, except agree with Webboo
    I'm sorry you don't believe in miracles
  • imposter2.0
    imposter2.0 Posts: 12,028
    CBA to read all that, so I'll just reply to the question in the headline - bonk is not caused by water.
  • VamP
    VamP Posts: 674
    That's like a bonk of a severe diabetic. Get checked out.
  • mike1-2
    mike1-2 Posts: 456
    That's not the bonk, I would suggest you had a major stroke.
  • kajjal
    kajjal Posts: 3,380
    As above go to your gp. The bonk is when your body really runs out of power / energy, what you had seems very different.
  • Hmmm... Thats a little concerning. Seemed to be the water that started it all off. Will keep an eye on it. Having read about the bonk, seems to have very similar symptoms, albeit quite a serius bonk. I understand you can slip into a coma from one? May have been dodgy sausage rolls!
  • meanredspider
    meanredspider Posts: 12,337
    Yes - go and see a doctor before trying to ride again. Even if your symptoms were hypoglycaemia, it wasn't the water that induced it nor should it have been exercise-induced for a healthy person over that ride.
    ROAD < Scott Foil HMX Di2, Volagi Liscio Di2, Jamis Renegade Elite Di2, Cube Reaction Race > ROUGH
  • StillGoing
    StillGoing Posts: 5,211
    Mike wrote:
    That's not the bonk, I would suggest you had a major stroke.

    Having had a stroke, I doubt it was that. Sounds very much like hypoglycemia. Exercise can induce hypoglycemia.

    Symptoms of hypoglycemia can also include:

    Being pale
    Feeling weak
    Feeling hungry
    A higher heart rate than usual
    Blurred vision
    Confusion
    Convulsions
    Loss of consciousness
    And in extreme cases, coma

    Conversely the symptoms of hyperglycemia are:

    Regular/above-average urination
    Weakness or feeling tired
    Loss of weight
    Increased thirst
    Vision blurring
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • Will make an appointment as a precaution although I'm not overly concerned. I went for a 10k run the day before, so feel it has more to do with sugars and dehydration. I need to be more mindful about what I ea and drink and when I do it!
  • cougie
    cougie Posts: 22,512
    Definitely not the bonk. And Who doesnt drink as they go? That's just weird.
  • cycleclinic
    cycleclinic Posts: 6,865
    low blood sugar happens you feel all dizzy and short of breath. turning the pedals becomes hard and stopping. It can happen to non diatebtics I get it sometimes. Eating always sorts it out. Of course a bonk is similar in it symptoms and I am not sure if there is any difference. Either way when it happens I have to stop and eat. It rarely happens now.

    When folk have said not a bonk I am not sure what they mean. A bonk if caught early enough is recoverable. A bonk happens when you run out of sugars to metabolise (hypoglycemia) and you need those to burn fats efficently as well.

    you can bonk on 35 mile ride depending on how well fueled you are before hand. I would not be over concerned your are alive and breathing that is normally a good sign.
    http://www.thecycleclinic.co.uk -wheel building and other stuff.
  • Thanks for your replies. I rarely drink during exercise, especially running as it gives me a stomach upset. 2/3 hours in the average UK weather is not an issue for me without a drink and I prefer to hydrate when I return. I should have stopped and had some sugar when I first felt the symptoms, but I didn't have anything and I was in the middle of nowhere, so pushed on. Looking at Cyclemeter and Strava my heart rate was normal and I had just finished a steep prolonged climb with little fuel during the day. Reading into this, water dilutes blood sugar. I wonder if I was on my last eb and then the sudden bottle of water diluted what blood sugar I had left. I recall craving sugar at this point and feeling tired, but pushed on. There was also a sudden temp drop at the top of the cliff (about 4 degs) which is probably why I suddenly felt the cold.

    I'll get my blood sugar and salt levels checked, but it would appear to be severe hypoglycaemia. I'm damn sure I ain't diabetic as I ate a whole bag of liquorice allsorts yesterday ;)
  • meanredspider
    meanredspider Posts: 12,337
    I'm damn sure I ain't diabetic as I ate a whole bag of liquorice allsorts yesterday ;)

    Not sure that means you aren't diabetic... In fact, if you make a habit of that, you might be headed that way.

    Drinking some water won't dilute your blood anything like enough to cause an issue unless you chugged several litres in one go.

    Like pretty much everything on a forum related to health, diet and fitness, nothing we say is going to match you precisely - we can only make general stabs in the dark. I'm glad you're going to get checked out. It may be absolutely nothing but it's rare to feel so bad in such circumstances.
    ROAD < Scott Foil HMX Di2, Volagi Liscio Di2, Jamis Renegade Elite Di2, Cube Reaction Race > ROUGH
  • mike1-2
    mike1-2 Posts: 456
    philthy3 wrote:
    Mike wrote:
    That's not the bonk, I would suggest you had a major stroke.

    Having had a stroke, I doubt it was that. Sounds very much like hypoglycemia. Exercise can induce hypoglycemia.

    Symptoms of hypoglycemia can also include:

    Being pale
    Feeling weak
    Feeling hungry
    A higher heart rate than usual
    Blurred vision
    Confusion
    Convulsions
    Loss of consciousness
    And in extreme cases, coma

    Conversely the symptoms of hyperglycemia are:

    Regular/above-average urination
    Weakness or feeling tired
    Loss of weight
    Increased thirst
    Vision blurring

    I forgot people on this forum didn't understand sarcasm. My mistake.
  • StillGoing
    StillGoing Posts: 5,211
    Mike wrote:

    I forgot people on this forum didn't understand sarcasm. My mistake.

    So what was sarcastic about your original comment? If you ever have the misfortune to suffer a stroke as I did, maybe you won't be so flippant about such a serious issue. :roll:
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • mike1-2
    mike1-2 Posts: 456
    Ah lighten up, you're not dead are you? We all suffer from things in our lives, having a 'poor me' attitude just means you drag them along with you. I didn't mean to offend but if you can't get past it then that's your problem not mine.
  • StillGoing
    StillGoing Posts: 5,211
    Mike wrote:
    Ah lighten up, you're not dead are you? We all suffer from things in our lives, having a 'poor me' attitude just means you drag them along with you. I didn't mean to offend but if you can't get past it then that's your problem not mine.


    Yeah you're absolutely right. Loss of motor function, speech etc is a jovial thing, especially at a young age with a 6 month old child. :roll:
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • mike1-2
    mike1-2 Posts: 456
    Obviously we're different people. I'd look on the bright side that I was still around to see my child grow up, but we're not going to agree so let's just get on with it.
  • AK_jnr
    AK_jnr Posts: 717
    My bonks I just feel like lying down in the nearest bush. I would actually enjoy the feeling if it was at the end of the ride... quite relaxing. Hahaha.
  • homers_double
    homers_double Posts: 7,977
    I think we need a more accurate description of the OP's day to decide what the problem is/was.

    There aren't enough details for my liking.
    Advocate of disc brakes.
  • davidof
    davidof Posts: 3,032
    Excessive water consumption can cause sodium levels in the blood to drop to dangerous levels:-

    https://en.wikipedia.org/wiki/Hyponatremia

    It is relatively common in marathon runners. I've not heard anything of blood sugar. I think you mean sodium which is what sports drinks are supposed to tackle.

    My experience of bonking is severe shivering, even on very hot days and faintness/weakness. Maybe some vision issues. Usually drinking a coke can get you going again.

    In the last decade I've bonked twice.

    Once on a hundred mile+ odyssey around the Vercors - the road I wanted to take was closed due to rockfall leading to a big detour with no cafes/shops/water points. I bonked at the 100 mile point a few miles from home. Normal really as I didn't eat or drink enough.

    The other time was a very short ride up to le Revard from Chambery, about 1h30-2h. I pushed hard from Aix les Bains and bonked at the summit. Luckily once I'd recovered after eating and drinking it was downhill back home.

    Both cases I got the shakes and had slightly blurred vision and had to lie down for half an hour.

    I think you probably bonked but not due to excess water drinking.

    Rule#5 applies.
    BASI Nordic Ski Instructor
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  • cld531c
    cld531c Posts: 517
    I get like that if Ive not eaten sometimes, excercising or not. My guess is the water was just a coincidence.
    Hope you are OK now.
  • svetty
    svetty Posts: 1,904
    Cold water ingestion can induce atrial fibrillation during exercise. A cardiac arrhythmia might explain your symptoms, a 'bonk' seems unlikely......
    FFS! Harden up and grow a pair :D
  • You sure it's not caused by riding through Dover?
    Road - '10 Giant Defy 3.5
    MTB - '05 Scott Yecora
    BMX - '04 Haro Nyquist R24 (don't judge me)
  • haydenm
    haydenm Posts: 2,997
    You sure it's not caused by riding through Dover?

    I've had a few issues with blurred vision, shakes, hunger, convulsions and lack of consciousness there in the past.

    Theres a cracking micro pub there called 'The Lanes'