View Full Version : Did I bonk?

April 21st, 2003, 02:22 PM
I went for my lunchtime swim today, did somewhat more laps than usual, maybe swam a little harder than usual. (I am not at all an accomplished swimmer, just a recovering runner.) After my shower I just wanted to puke. I broke out in a cold sweat, felt generally rotten, and quietly wished for death. I had to lie on the bench for about 5 minutes before I could finish getting dressed. This happened only once before, 27 years ago when I ran cross country.

Questions: Is this what athletes call "bonking?" What is the physiological condition that causes it -- build-up of lactic acid? Running out of blood glucose? Not enough oxygen in the brain? Dehydration? What is the preventive -- Big breakfast? Stretching? Being in better shape? Wearing boxers rather than briefs?

Thanks for your help.

jim clemmons
April 21st, 2003, 03:36 PM
Man, sounds like the onset of the flu! Did you eat anything before you swam? If you didn't, you need to eat, without fail. If you did, it still sounds like the flu.

Gail Roper
April 21st, 2003, 04:02 PM
This could be serious. I recommend that you see your doctor for a check-up. This happened to me and it was a heart arrythmia.

April 21st, 2003, 04:43 PM
Okay, maybe I was a little too dramatic in my initial post. I should add that felt much better after the five minute rest, and completely fine after I had a sandwich later in the hour. It's probably not the heart -- I recently had a stress echocardiogram (part of an executive health screening), and the doctor said it was excellent. My current money is on either low glycogen (I should have eaten more), or high lactic acid (I'm out of shape).

April 21st, 2003, 06:07 PM
Could be a vasovagal reaction, which can occur after very strenuous exercise. Essentially it's similar to what happens when you faint and involves the autonomic nervous system. Perhaps you were a bit dehydrated. This is usually benign but you should of course consult your physician (especially if it happens again).

April 22nd, 2003, 10:32 AM
Sounds a lot like low blood sugar to me, especially since you say you felt better after a sandwich. Do you swim on an empty stomach? If so, you might try eating something to "fuel" your workout. I'm fond of ZonePerfect bars or wheat toast with cream cheese, and I usually eat it before leaving for the pool (giving it 30-45 minutes to settle).

April 22nd, 2003, 05:40 PM
Well, I did something stupid twice. Went out in race speed in a 100 yard breastroke workout and my heart was beating very fast and it took me about 5 mintues to recover. Also, had to sit down after a workout because I felt very light headed. I did sprint kicks and sprint butterflys before my conditioning was really for it. You have to be careful sometimes coming from a running background and I guess that you are also at least in your late 30's to early 50's. Another reason to be careful at workouts.

April 22nd, 2003, 06:02 PM
More than likely, it's because you did the extra yardage and pushed yourself harder. I've been through the same experience, both when I've begun swimming after a long hiatus (and not even pushed all that hard), and when I've upped my yardage or effort too quickly. Never something to worry about, but the feeling is enough to remind you to increase yardage/pace more slooooowly.

Kevin in MD
April 23rd, 2003, 05:40 PM
I suppose some people use the term bonk in deifferent ways.

In triathlete circles the term is reserved for use when describing glycogen depletion. The most identifiable characteristic is that you are working really hard, high perceived effort but your heart rate stays low. It would be out of the ordinary to see someone who has bonked be nauseous.

I suspect that the nausea was from very high intensity swimming and the problems that tends to cause. Not from glycogen depletion.

Of course the nausea could have been from something else alltogether.

April 24th, 2003, 03:44 PM
The classic symptoms of a vasovagal reaction are profuse sweating, nausea, and lightheadedness (due to a fall in blood pressure and heart rate). Not uncommon after strenuous exercise and usually benign unless it becomes a frequent occurence.

April 25th, 2003, 10:44 AM
Thanks, everyone. After reviewing your responses and studying related websites, I believe that the winner is: Vasovagal Reaction.

For reference -- Wang, Sakaguchi and Babcock (THE PHYSICIAN AND SPORTSMEDICINE - VOL 25 - NO. 5 - MAY 97) have written that "Vasovagal reactions are reasonably well accepted as a cause of postexercise syncope [fainting]. Vasovagal reactions consist of varying degrees of bradycardia [slowing of heartbeat] and vasodilation [widening of blood vessels]. These reactions can range from pro-dromal [early sign of] vagal symptoms such as nausea, pallor, diaphoresis [profuse sweating], and/or blurred vision, to presyncope [light-headedness] or outright syncope."
This describes my episode accurately. As I understand it now, some dilation of the blood vessels is normal during exercise, as is slowing of the heart rate immediately afterwards. In combination, these may result in a mild, temporary shortage of circulation to the brain, leading to the observed symptoms. To support my conclusion I note that the symptoms began not during exercise, but while showering (i.e., I stopped moving my legs, which further decreased circulative effect), and equilibrium was restored when I put my head down for several minutes. To prevent recurrence -- I have to get in better shape, don't overexert, and cool down after workout.

"Bonking" seems to be a different effect, as it happens during exercise (rather than after), even to extremely fit long distance runners and cyclists. It has to do with depleting glycogen stores.

March 10th, 2007, 03:12 PM
I thought I would unearth this one. I had the same experience as the initial poster at my workout today. I also was thinking "did I bonk?". I'm still kind of curious about how the whole thing happened. I wonder how common this is.

My Day...
At 6:30 A.M. I had a bowl of cereal. 16 oz water
At 9:00 A.M. I had Eggs, Toast, Ham, and 1/2 an Orange. 20 oz water.
Homework til 10:30.
11:00 - 12:30 Swim: Slightly less yards than normal. Stretched out over an hour and a half instead of 1 hour. Much higher percentage of sprinting than normal. The whole thing felt off, it took much longer than usual to warm up, etc. I most of my 24 oz water bottle, we'll call it 20 oz.

NOW here's in interesting thing that was mentioned earlier here. I was wearing a heart rate monitor as usual. When I saw the workouts results I was SHOCKED that my maximum recorded heart rate was about 10% lower than my normal maximum recorded heartrate in any given workout. I felt those sprints were kicking my butt even though I didn't go as fast as I would have liked.

I felt fine until I was finishing up my shower. Total Nausea, lightheadedness, general sense that standing was not a good idea. I sat wrapped in my towel for about 20 minutes feeling like the plague had hit me until I forced myself to get dressed and get out of there. I called my husband and asked him to have a pb&j sandwich with some chocolate milk waiting for me when I got home. (If he hadn't raided my purse the night before for pick-up hockey money I would have been able to go to the vending machine, so this was plenty fair). I generally felt much better at the sandwich but I still feel like I haven't eaten nearly enough today.

I wasn't dehydrated. I had a reasonable amount of fuel in my system. I only did between 2400 and 2800 yards (I did 12 minutes of working on breaststroke turns, so I didn't really calculate that part) in 1-1/2 hours. I normally do roughly 3000 in an hour. I wasn't worn out from other activities.

What gives? Maybe time will tell that this is a precursor to being sick. But it seems to be random extreme nausea.

I wonder how common this is?

March 10th, 2007, 03:21 PM

Michelle I had sometign like this Monday thru Wednesday. I'd get my dizzy, shaky spell about 3pm. I nixed swimming monday thinking I was going to be geting real ill, my son had stomach issues last weekend. Nothing happened except the dizziness, and feeling a bit weak. I slept it off for an hour and felt better but tired.
Wednesday I forced myself to go swimmng and felt sluggish. I did 100 yards of warm up and breast drill, fly and back work then I took a bathroom break.
While in the bathroom I found breathing a bit difficult...like I was going to faint. I got back into the water hugged the wall and felt much better...I then swam 1800 of Front crawl and felt very strong.
I think some bug is doing the rounds again and maybe the air temperature change from the pool to the locker room caused my body to react in a shocked way because of the slight illness thing.

Obvioulsy it could be something totally different but since we're not millions of miles apart... I figure I'd share my "odd feeling" with you. Sounds liek something similar in parts. My appetite was not decreased in this spell either. I think the forced swimming Wed helped my system buck up and fight it off...