Dizzy/Light Headed during really fast ride or climbing. Any ideas?

There a host of things which can cause those symptoms, only one of which is blood pressure:

• dehydration
  
• cardiac issues
  
• pulmonary issues
  
• circulatory issues
  
• metabolic issues
  
• hormonal issues
  
• ....
  

Note that when you get your blood pressure taken for a physical, it's not done on a bike, at effort, and may bear no relationship to your blood pressure at a given moment on the bike. Also note there is no reason to believe that you are better at dealing with a decreased or altered level of consciousness better than anyone else, especially since you have no idea what is causing those changes in you. You need to see a doctor about these issues. That is the only way you are going to get any definitive answer or have any chance at finding a definitive answer. Also keep in mind that the number of things that could cause your symptoms that wouldn't necessarily show up in a physical are, for all intents and purposes, innumerable.

What I suspect is happening is that your body's demand for oxygen and disposal of CO2 has exceeded your cardiorespiratory capacity. Once you exceed peak capacity, oxygen levels drop and CO2 levels increase resulting in light headedness. Your body has a finite capacity to exchange and transport gases. When this level is exceeded, you begin anaerobic metabolism (without oxygen) which cannot be sustained at peak levels for very long. Anaerobic metabolism is great for short bursts at high intensity but sucks for endurance. You can improve your cardiorespiratory capacity through HIIT but every athlete has his/her limit.

Just see a doctor. The reliability of online diagnoses is right up there with the accuracy of astrological predictions.

Cat5Hurricane ---

My internet advice is to not ride so hard. That certainly solves the problem.

If I had your problem and could recreate it at will, I would go see a sports doctor - one with a bike trainer in his office. Take my shoes. Wear my shorts.

Get a check up, it'll only cost a small amount of money and time - it could save your life.

By all means, get a checkup. You'll want to rule cardiac or other serious causes. I should have said that in my first post as I did not intend my comments as a diagnosis, just discussion of a common cause of lightheadedness in athletes. As others have mentioned there are other possible causes and a checkup is never a bad idea. I'm an advocate of annual visits to a physician even when you have no complaints.

Note that repeatability has nothing to do with whether you should see a doctor or not. It can happen that certain medical issues have symptoms that are not regularly repeatable, and it happens there are a lot of those. It also happens that a lot of those medical issues without regularly repeatable symptoms are serious. I certainly wouldn't base my health solutions upon advice about only seeing doctor if symptoms are repeatable, especially if that advice comes in an internet forum from someone who isn't a doctor.

I agree with everyone else who has posted here. The best thing you can do is assume the worst and get checked out by a doctor as soon as possible. The worst thing you can do is to continue in your belief that because you used to box you are somehow better than other people at maintaining awareness of your surrounding when you get dizzy or lightheaded. That kind of total disregard for your own health could turn on you in an instant. The last thing you need to happen is to completely pass out while riding in a group at 27+ mph. You could be seriously hurt and could potentially take out several other riders and put their safety at risk as well. So please, please go get checked out by a doctor. We all certainly hope it is something as simple and easily corrected as an iron deficiency too. But let a doctor diagnose you, not us. Keep us posted!

I am not sure that going to a doctor and saying "I get dizzy when I ride my bicycle" is going to produce any worthwhile results.

The process works better if you can reproduce the problem.

---

I have insurance. I have enough savings to pay for any treatment. I would never go to a doctor and say "I get dizzy when I bicycle."

Most likely the problem is caused by a reduction in blood flow to the brain due to a change in effort. I can cause such a change by riding at 90% effort for a reasonable length of time, getting off my bike, and bending over to change my shoes. After I straighten up and take several steps I get dizzy. I cured my problem by sitting down to change my shoes.

Behavioral changes may do as much good as a visit to a doctor.

I expect there is a greater chance of injury on a group ride because someone makes a bicycling mistake rather than this fellow passing out.

+1 for a visit to the doctors. Clearly explain your condition and concerns and they will be able to take the proper steps to diagnose your problem.

Thanks to everyone for the comments. I know I posted this back in November but I wanted to update. First, the lightheadness has gotten more prevalent. It happens most rides where we get going 25+ MPH on the flats or try to keep our speed up on hills. I did get a heartrate monitor this Christmas so that has given me some data. I also ruled out iron after my initial post. Because of the unusually warm winter and pressure by friends to ride during the winter, after a couple months off, I started riding again in January. I would also add that I gained 20 lbs from September to the first of January because I didn't cut my calories back as my cycling decreased. On one of the first rides back, I tried to keep up with the better climbers and it just completely drained my body. I was at 172 bpm at the bottom of the hill (we just crested a very small hill prior to that but were maintaining speed). Once I got up to about 185-187, I just could barely turn the crank. My heartrate would eventually spike up to 195 and I was literally going 4-6 MPH. Everyone waited for me at the top of the hills but I just kept going because at this point, my head was spinning and I didn't want to stop. For the rest of the ride (~8 miles/30 mins), I never recovered. My head was in a whirlwind. I had to focus 100 meters down the road just to stay on my bike. Reaching down for my water bottle or to the right to make sure a car wasn't pulling out on the road and I would start zig zagging back and forth in a 3 foot range. However, if I just stay focused down the road, I could keep my balance and the bike straight. It took about 10 mins to recover when we got back. I would add that I was dieting at this point to lose the extra weight so I had cut my caloric intake by 1000 calories and had not eaten since lunch. Hence that probably contributed a lot. That was enough to make me schedule an appointment with the doctor. I did a glucose test and he said I was borderline hypoglycemic. My guess is that maintaining a high heartrate (170s+) for extending periods of time is dropping my blood sugar to dangerous levels. A few people on the ride recommended the importance of eating before (and even during a ride) so I have been doing that and it has improved.

However, my average rides, I am in the 156-172 bpm range depending on distance, course and average speed. Last night I did an relatively slower ride (20 miles, 17.0 avg, a few 5-10% short hills) and i averaged 158. I got dizzy near the end trying to keep up in the 20-25 mph range and really attacking the hills. The hills are what really spikes my heartrate (duh, I know!). My fitness has improved since starting back in January, I lost 10 lbs in January alone (I want to lose 20 more to get down to 185 by end of April), and I am doing better eating before rides (and taking GU packs and glucose pills for rides over 20 miles), yet I still am getting lightheaded on almost every ride (almost always on hills). I would add that as I improve, I am trying to push myself harder. I have gone from people waiting 5 mins for me to get up a hill to being near the front now, but at the expense of feeling lightheaded because of being at a high heartrate. Usually on any climb (even a little 3%er), my heartrate will be in the 170's. I can get up to about 182 before the body pushes back and I have no energy in the legs (getting better as my fitness improves) or get lightheaded. It has gotten better as my conditioning has improved, but as I said earlier, it used to happen every once in awhile, not routinely like now.

Quoted post said:

Originally Posted by Myosmith [IMG]/img/forum/go_quote.gif[/IMG]

What I suspect is happening is that your body's demand for oxygen and disposal of CO2 has exceeded your cardiorespiratory capacity. Once you exceed peak capacity, oxygen levels drop and CO2 levels increase resulting in light headedness. Your body has a finite capacity to exchange and transport gases. When this level is exceeded, you begin anaerobic metabolism (without oxygen) which cannot be sustained at peak levels for very long. Anaerobic metabolism is great for short bursts at high intensity but sucks for endurance. You can improve your cardiorespiratory capacity through HIIT but every athlete has his/her limit.

I have felt this was the issue. I know there are other factors with the weight gain, taking a couple months off from cycling and hence losing conditioning, dieting, borderline hypoglycemia, but what you posted above is what I felt I was experiencing...just lack of oxygen to brain and muscles. I do want to improve because I want to be limited by heartrate or lactic acid only...not recovering from being lightheaded. Can you tell me what HIIT is? I will google it after this reply but please follow up on that. Thanks again!!!

Quoted post said:

Originally Posted by alienator [IMG]/img/forum/go_quote.gif[/IMG]

Just see a doctor. The reliability of online diagnoses is right up there with the accuracy of astrological predictions.

I do realize that but you just hope someone will be going through what you have and can shed some light on focusing on the root of the problem. I take every opinion with a grain of salt but you can build up your understanding of the issue though these forums.

Quoted post said:

Originally Posted by An old Guy [IMG]/img/forum/go_quote.gif[/IMG]

Cat5Hurricane ---

My internet advice is to not ride so hard. That certainly solves the problem.

If I had your problem and could recreate it at will, I would go see a sports doctor - one with a bike trainer in his office. Take my shoes. Wear my shorts.

Lol! I am too competitive not to want to ride with the guys I do. You have great advice, but that is an individual decision. 🙂 Just to give you a head's up, back in January, 20 of us did a 50 mile ride. I got dropped on the first hill about 5 miles into the ride and did 40 of the 50 miles solo. We also were riding into a constant 30+ MPH headwind (13.9 MPH average for first 25 miles, 23.9 MPH on the way back solo maintaining an average heartrate of 174). Other people were getting dropped as well but I was the weakest that day. While I pressed on to the midpoint, 9 others found it too hard and turned around making it a 30 mile ride for them. That is where I differ. I don't mind suffering. I would prefer not, but I know I can only get stronger. The week before 4 others turned around on a 35 mile ride because they were struggling to keep up. I stayed and rode the last 10 mile alone. On the ride in early January I discussed above where my head was spinning for ~45 mins constantly, I could have turned off with 4 miles to go to my house and had my wife drop me to pick up my car but I pushed on. My point is, I may not be the strongest rider on some day, but I won't be the one quitting or taking it easy unless my body forces me to.

I will take your advice on the sports doctor and that is probably the logical next step. Thanks!

Quoted post said:

Originally Posted by An old Guy [IMG]/img/forum/go_quote.gif[/IMG]

I am not sure that going to a doctor and saying "I get dizzy when I ride my bicycle" is going to produce any worthwhile results.

The process works better if you can reproduce the problem.

---

I have insurance. I have enough savings to pay for any treatment. I would never go to a doctor and say "I get dizzy when I bicycle."

Most likely the problem is caused by a reduction in blood flow to the brain due to a change in effort. I can cause such a change by riding at 90% effort for a reasonable length of time, getting off my bike, and bending over to change my shoes. After I straighten up and take several steps I get dizzy. I cured my problem by sitting down to change my shoes.

Behavioral changes may do as much good as a visit to a doctor.

I expect there is a greater chance of injury on a group ride because someone makes a bicycling mistake rather than this fellow passing out.

It is basically what you are alluding to. When I am riding at 100%+ of my "theoretical heartrate", this is when the issue gets problematic. Most of my rides, my average is 90%. My goal is to get this down to 150-155 bpms or ~85% while improving in my endurance and climbing. I wish I had had my heartrate monitor last year when I was peaking and climbing Mt. Evans or doing one of the many century rides I did so I could compare to when I was peaking last August. As I said, i am riding with a lot of guys who took no time off (and who I had no issue keeping up with them and who I felt were weaker than me when I peaked last August) and I am trying to keep up with them after two months off when I started riding again in January so my ability is below their's currently; I gained 20 lbs in 4 months and that makes a momumental difference on climbs where I am being affected the most; and the borderline hypoglycemia I think I have had for well over a decade but just recently diagnosed coupled with the fact that I was dieting hard when the problems intensified and wasn't eating before or during long rides. Obviously I have improved some of these issues the past month and a half and the lightheadness is getting better. I will update again in a month or so because I think it is valuable to see these kinds of problems, actions to try to correct them, and updates later on.

Thanks to everyone again for the advice.

Cat5Hurricane said:

I do realize that but you just hope someone will be going through what you have and can shed some light on focusing on the root of the problem.  I take every opinion with a grain of salt but you can build up your understanding of the issue though these forums.

That's right: you can absolutely build up your understanding of the issue with blind, speculative guesses. That's the way to do it. It's funny that the doctor had an answer. See, he's trained for that. Everyone on these forums? Well, they're not trained to diagnose medical issues, especially at a distance, with no working knowledge of anything to do with the person in question or medicine. You do whatever puffs your skirt up. I'm glad your doctor had a real answer, one founded on objective analysis and proper diagnostic technique.

Quoted post said:

Originally Posted by alienator [IMG]/img/forum/go_quote.gif[/IMG]

That's right: you can absolutely build up your understanding of the issue with blind, speculative guesses. That's the way to do it. It's funny that the doctor had an answer. See, he's trained for that. Everyone on these forums? Well, they're not trained to diagnose medical issues, especially at a distance, with no working knowledge of anything to do with the person in question or medicine. You do whatever puffs your skirt up.
I'm glad your doctor had a real answer, one founded on objective analysis and proper diagnostic technique.

Did you really miss the point of that? Serious, "whatever puffs my skirt up"? Are you really that much of a troll you can't come here and have a honest discussion? Do you feel manly being a bit of an ass? Seriously, how old are you??? I probably made the wrong assumption that I would be speaking with reasonable adults!

I came on this forum because I hoped someone else may have experienced the same thing and could shed light on the subject. You do realize others who cycle may just miraculously experience the same thing and can share on their experiences dont' you??? I don't have to accept each answer as the definite solution to my issue but forums are a great means of sharing information...regardless of the accuracy. I would hope that I could weed through the [censored] and those that make sense. Obviously someone asking if I am hydrating myself would be a good reply. Someone saying that they fell off the side of a ladder and started getting dizzy on rides soon after, less so!!

So far with the doctor, he confirmed something I have suspected for about 15 years now so it wasn't some great revelation that I may be borderline hypoglycemic. I sort of figured that out 15 years ago when I would get very shaky during lunchtime but could resolve it after about 2 minutes of eating. However, Myosmith suggested something I had already figured was the underlying issue (and seemed to confirm by comparing the incidence of my lightheadedness to my heartrate at that time) and An Old Guy had a good suggestion about going to a sports doctor (something I probably wouldn't have thought about after my initial doctor's appointment).

But do come back and get in that last witty sarcasm of yours because one thing I have learned with the trolls and kids who like to act like asses is they won't be satisfied unless they get that last word in...so I will reserve that right for you!

Actually Cat5 Hurricane I agree with Alienator; he may not have put it to you politically correct to appease you in that regard, but he is right. It's your life you can do with it whatever you want; we're trying to be concerned for our fellow cyclists and yet we have one, you, that doesn't seem to care about your own self, or you're scared of doctors so much you shy away. I hope you don't have a family who may miss you. If I had gotten dizzy on more then one ride I would have ran not walked into the doctors office because I never gotten dizzy in 40 years of riding so something must be wrong. And some docs do very short tests that don't review a lot, so I would have gone to sports doctor and had a stress test done since that's when the symptoms occur is when your under extreme physical stress; I read nowhere in your post that your doc did that. And I would have brought in all my data what caused the dizziness for further info for the doctor to look at. I really don't care what some dope said on a forum, by the time I did that I could be dead!! Please don't think I'm saying your doctor is wrong, he may be right, but your still experiencing issues, you need to have a doctor replicate the conditions when the dizziness occurs while your hooked up. What's the worst thing that can happen by getting a stress test? You find out your all right? You wasted some time? Maybe wasted a few dollars? Personally the piece of mind finding out that my heart is good would be worth the waste of few dollars and time.

So I guess I'm a troll too for wanting the best for fellow cyclist.

Troll, troll, troll my boat...fine, here's a better troll song:

Quoted post said:

Originally Posted by Froze [IMG]/img/forum/go_quote.gif[/IMG]
It's your life you can do with it whatever you want; we're trying to be concerned for our fellow cyclists and yet we have one, you, that doesn't seem to care about your own self, or you're scared of doctors so much you shy away.

I have known a couple people over the years who ether had a fear of doctors... or a fear of a treatment, or fear of having an illness or condition, and avoided seeking help for that reason. I have also known people with addictions and/or compulsions that avoided medical treatment for fear of being exposed.
I knew one gentleman who finally fell to the floor at work unable to stand, yet still refused emergency medical treatment. His condition turned out to be a simple ear infection. Why he had avoided proper treatment prior to his collapse is anyones guess.
Cat5Hurricane is likely just using the forum. Here he can limit his exposure. Yet still feel as though he is making some progress with his illness.

While there are those that will go see a doctor for a head cold, there are others who refuse to go for any reason. I had friend who hated docs but his wife along with myself was able to actually get him to see the doctor and had a heart stress test done because he wanted to start excercising after being a couch potato for 35 years. I also told him to take it very slow for the first 3 months by walking around the block once and slowly build up from there. Instead he joined a gym, the first day he did all the machines and finished up on a spin cycle. Shortly after the spin cycle he felt pain in his chest, hating doctors and thinking since the doc said he was good he went on to work, where he died. He actually called his wife when he left the gym and told her he felt tired and felt the pain, his wife told him to go to the hospital, he just laughed and said the doc said he was good to go and the pain was just heart burn. His heart burned up alright!

Quoted post said:

Originally Posted by Froze [IMG]/img/forum/go_quote.gif[/IMG]

Actually Cat5 Hurricane I agree with Alienator; he may not have put it to you politically correct to appease you in that regard, but he is right. It's your life you can do with it whatever you want; we're trying to be concerned for our fellow cyclists and yet we have one, you, that doesn't seem to care about your own self, or you're scared of doctors so much you shy away. I hope you don't have a family who may miss you. If I had gotten dizzy on more then one ride I would have ran not walked into the doctors office because I never gotten dizzy in 40 years of riding so something must be wrong. And some docs do very short tests that don't review a lot, so I would have gone to sports doctor and had a stress test done since that's when the symptoms occur is when your under extreme physical stress; I read nowhere in your post that your doc did that. And I would have brought in all my data what caused the dizziness for further info for the doctor to look at. I really don't care what some dope said on a forum, by the time I did that I could be dead!! Please don't think I'm saying your doctor is wrong, he may be right, but your still experiencing issues, you need to have a doctor replicate the conditions when the dizziness occurs while your hooked up. What's the worst thing that can happen by getting a stress test? You find out your all right? You wasted some time? Maybe wasted a few dollars? Personally the piece of mind finding out that my heart is good would be worth the waste of few dollars and time.

So I guess I'm a troll too for wanting the best for fellow cyclist.

Troll, troll, troll my boat...fine, here's a better troll song:

I have no issue with someone being direct. I am quite that way, but I do it as respectful as I can, not laced with insults. I called him out because of the way he decided to respond. The internet is where people seem willfully delighted to go out of their way to be asses because of the anonymity. If you noticed, I had a lot of DIRECT responses to my original post I was respectfully appreciative of. Heck, even his first response after my original post was one I respected because he was trying to be helpful rather that snide. I didn't post in this forum as an alternative to the doctor but to see if anyone else had experienced this. I would add, it was only happening when I was pushing myself to my max for a sustained period...not intermittingly and randomly.

Also, I have no issue going to the doctor. I usually go the first moment I feel bronchitis coming on; right after a bike wreck this summer just to make sure nothing was broken; after my lower back went into spasm after lifting; etc. I just don't go everytime I get a sniffle or something out of the ordinary happens. When I wrote my original post last year, it was something that only happened a few times but was starting to happen more frequently as I got up in the high intensity part of my workout (high speed on flats and climbing on hills...I went from riding with guys who just maintained some comfortable pace up the hills to guys who maintained speed up the hills) so I came to a forum site about cycling to see if anyone else had ever had a similiar scenario. It wasn't until this January it was becoming "less rare". Consequently, I went to the doctor as a result of a bout that lasted 30-45 mins as I rode.

I finally got a heartrate monitor this Christmas so I got at least another parameter of data I never had before. What I found out is that I don't get dizzy unless I get up in the low to mid 180's and I sustain that effort ~30 seconds or more. As a result, that seems to indicate that Myosmith's post was most likely spot on:

What I suspect is happening is that your body's demand for oxygen and disposal of CO2 has exceeded your cardiorespiratory capacity. Once you exceed peak capacity, oxygen levels drop and CO2 levels increase resulting in light headedness. Your body has a finite capacity to exchange and transport gases. When this level is exceeded, you begin anaerobic metabolism (without oxygen) which cannot be sustained at peak levels for very long. Anaerobic metabolism is great for short bursts at high intensity but sucks for endurance. You can improve your cardiorespiratory capacity through HIIT but every athlete has his/her limit.

This isn't to preclude the possibility of other factors like alienator stated in his first post. I came to this forum to get feedback from others who may have had similar problems. The suggestion to go see a sports doctor is one I hadn't even thought of. So that and Myosmith's suggestions obviously justified my thoughts about coming here for advice, so in that regard, this post and this forum did what I had hoped to get from it. I had suspected Myosmith's explanation. The only variable was that the lightheadiness was starting to become more frequent. This year it makes sense as I took several months off and started riding again with people who never stopped. Hence I was trying to stay at the front of the group like I usually do, but now I lacked the conditioning I had say back in September. Add to that I was 20 lbs heavier and it isn't surprising I was struggling up the hills and getting dizzy trying to maintain speed with my mates whose form had never dropped off due to inactivity.

Alienator mentioned hormonal issues. I used to put on topical testosterone (see, I went to the doctor for that too). I went off it late last year because my wife and I wanted to have a baby so I switched to the Testipill (surgical time released pellets). The major thing I noticed on the testosterone, I never got tired. I don't get tired in the late afternoon at work, I don't get tired from exercise unless I have gone to some extreme level. For the past two months, I have been getting fatigued. The pellets were suppose to last 6 months. My guess is that they lasted about 3.5-4 months (consistent with what I read on some forums...tell me it isn't so! LOL!). I am suppose to get my next injection on Friday so Sunday I decided to pull on some leftover gel I had several hours before a ride. About 15 of us averaged 19.1 MPH for 42 miles. Looking back at my heartrate data, that should have put my average heartrate around 167-172 (roughly). I actually averaged 160 which was my lowest for a ride where the average was over 16.5 MPH. On top of that, on the final big hills home, I just attacked the hills and put about 4-5 minutes on the entire group over the last 3-4 miles. For the first time this year, I finally felt strong on the hills. Also what I noticed is that my heart was topping out ~167-175 on those hills. Add to that I was standing on my pedals racing up, it should have easily gone into the mid 180's. Another interesting observation is that when I would crest the summit and have to start pedalling on the next hill, my heartrate would drop to the low 140's (as opposed to 162-165ish). So I do believe the testosterone was improving my performance while helping my heart to recover faster...hence why I had my fastest ride of 2012 while also having one of my lowest heartrates.

I know this has been a long response, but I do hope that if someone is going through what I did, they will at least have my experiences and these responses to help them in their decision. If this continues a month from now, I will go see a sports doctor for more thorough tests. My original doctor only confirmed something I have known for 15 years. The reason I suffered that 30-45 min bought in January is because I stayed up in the 180's for about 4 minutes and my body didn't recover. Moreover, my blood sugar dropped due to the workload on my body and the fact that I was dieting (lost 10 lbs in January cutting about 1000 calories from my diet and upping my workouts). I have done much better since trying to eat more prior to my rides. Now I know the importance of keeping GU gels on me and glucose pills on longer rides. Over the past two weeks, my conditioning has improved and the incidence has decreased....moreso because I am more cognitive of my heartrate and how long I allow myself to stay in Zone 5.

In summary, I don't think it was one single thing but a multitude of reasons:

-Myosmith's post is most likely the reason.
-Compound that with caloric restriction and several months off while trying to stay with other cyclists who had not dropped off and I was putting myself at an effort that was outside my tolerance and led to secondary issues like a drop in my blood sugar.
-Add that I was 20 lbs heavier trying to ride up hills at 215 lbs like I did when I was more fit months earlier at only 195 lbs. My goal is to be at 185 by the end of April.
-Add to that a low level of testosterone was preventing my body from recovering and hence as I fought to stay in the group, the body pushed back more and the symptoms exacerbated.
-An old guy's response to see a sport's doctor would be the next likely step if this continues, but now I know where my heartrate can be detrimental to my performance (along with food prior/during to rides) and I have done better at managing how high I let it get (or more specifically stay at) and am probably looking at it several times a minute. So far it has more than paid for itself.

Please see the secretary on your way out to collect your internet medical degree.

Quote:
Originally Posted by alienator [IMG]/img/forum/go_quote.gif[/IMG]

Please see the secretary on your way out to collect your internet medical degree.

Thank you...now run along and let the adults talk for awhile!