Temporary vision loss after exercising

June 4, 2007 4:25 PM

Why did I experience temporary vision loss after exercising at the gym?

I am epically unfit, and in an effort to improve my endurance and general energy levels I recently signed up at the local gym, and made an appointment with a trainer to teach me how to use the various machines and other things, and generally instruct me in how to exercise.

So last night, he took me through how to do a warmup, how to use the weight-training equipment, and then how to use the cardio equipment, and then how to stretch. It wasn't a full workout, it was more like he would demonstrate and then watch me to see how I did, correct my form, work out what my limits were and so on.

Even so, by the time I finished (on the rower), I was feeling a bit bizarre - 'lightheaded' comes close to it, but doesn't really capture it. I was wobbly and feeling both hot and cold simultaneously, and feeling a bit disconnected and unreal. I could walk okay and understand what was being said to me perfectly. But after we got through the stretches and the session was over, I suddenly felt it would be a good idea to sit down.

As soon as I did so, all the things I had been feeling up until then just seemed to get ten times worse, I wasn't struggling to breathe, exactly, but I couldn't lift my arm or do much more than wobble my head around or murmur. At this point my vision went. It didn't turn off suddenly, it was more gradual than that, but it still went before I realised what was happening. All my other senses were intact and I decided that panicking was just going to make things worse.

The trainer must have seen me groping around weakly and put my water bottle in my hand. I managed to raise it and took 2-3 swallows of water. A few seconds later I could distinguish between light and dark, and then I could see distinct silhouettes, and then my sight came back. The whole thing, from sitting down to getting up again, may have lasted 2-3 minutes.

My questions (which probably overlap) are these:
1) Why did just my vision go? Why didn't I just pass out or lose multiple senses? What was happening in my brain?
2) Why did it happen when it did, i.e. after I finished exercising and not during?
3) What was the likely cause? The return of vision and easing of symptoms seemed to coincide with drinking some water. Is this a clue or just coincidence? I may very well have been drinking less than I should have throughout the session - by the time I got off the weights, my arms were twitchy and I kept missing my mouth with the bottle.

posted by Ritchie to health & fitness (19 comments total)

No idea what or why this happened, without knowing your medical history and examining you. You should really see a doctor ASAP.

Sounds like you were syncopal or pre-syncopal (passed out or almost passed out). I doubt the drinking water fixed your vision.
posted by gramcracker at 4:30 PM on June 4, 2007

Sounds like you almost passed out to me as well. Your blood pressure could well have gotten screwy if you were unused to strenuous exercise and didn't drink enough water on top of that. Sitting down for 2-3 minutes would probably have been enough time to get your blood pressure back up to snuff.

But it's impossible to say from here with any kind of certainty; if it happens again I'd see a doctor.
posted by Justinian at 4:34 PM on June 4, 2007

I'm sure some doctors will chime in here, but this is exactly the kind of complication I experience periodically with low blood pressure (the kind called orthostatic hypotension). It first affects my autonomic nervous system, making me feel hot or cold or like it is hard to breathe, and then, if I don't sit down and drink some water, my vision will start to go. If you have problems with low blood pressure, about all a doctor can tell you to do is to drink more water, so that you increase the amount of blood volume. But I doubt the water was able to help that quickly - probably sitting down for long enough fixed it for you.
posted by emyd at 4:38 PM on June 4, 2007 [1 favorite]

That sounds like how I feel when my blood *sugar* goes way low. I go dizzy and the world goes to black, and I have to sit down or bend down lest I fall over. Then it passes.

But they always say to check with your doctor before starting a new workout routine, so this might be a good time to check in.
posted by iguanapolitico at 4:46 PM on June 4, 2007

My vision always starts to fade and then fades completely before I pass out (I usually feel cold, but not hot). I pass out comparatively often and it sounds very similar to my usual experience.

I've passed out from hunger, having my arms kept above my head for an extended period, mild pain, hot showers before I've eaten breakfast, having my blood taken (most often; trifecta of needle phobia, tiny unfindable veins, and blood sugar weirdness). I'm not diabetic, but do probably have some insulin resistance.

(For example, as my vision is mid-fading I'm often able to say to whomever is around "I'm going to pass out, can you help me get on my back with my legs in the air?" or sometimes only "I'm going to pass ou...")
posted by birdie birdington at 4:47 PM on June 4, 2007

That sounds scary - I'd go see a doctor if only for reassurance that it's still safe to continue working out.
It sounds like it might be a blood pressure problem. Are you on any medication?
posted by Laura_J at 4:49 PM on June 4, 2007

This same exact thing happened to me, except I actually passed out standing up. When I woke up, it felt like I'd been asleep for hours, but my trainer was flicking water in my face as he eased me to the floor.

Sounds like possible low blood sugar combined with a strenuous new workout. Next time you head to the gym take lots of water and 16 oz of juice. While you're working out, drink half the OJ in small sips and have plenty of water. After you've showered and dressed, drink the rest of the OJ with breakfast.

Also what iguanapolitico says.
posted by infinitewindow at 4:59 PM on June 4, 2007 [1 favorite]

Your system just rejected the hell out of the level you were pushing it at. Learn this lesson, don't repeat it.

First, see a doctor. The symptoms you were describing were not a normal response to even very strenuous exercise.

Second, when the doctor clears you to exercise again reassess the level of exercise you are going to be doing down. It should probably be somewhere on the order of long, and eventually fast, walks, a few push-ups and a few sit-ups for the first month. After that, consider returning to the gym.

I know that sounds like too little exercise but if the only regular physical activity you have been getting for the past 2+ years is walking from the office/house/store to the car, that is the level you should be aiming at.
posted by 517 at 5:14 PM on June 4, 2007

Yep, you were about to pass out. But I wouldn't discount simple dehydration as a cause (although sitting down probably got you back to normal moreso than drinking water). I have nearly passed out many times while playing sports, and it's almost always been when I hadn't drunk much water that day. It's easy to forget about, but drinking lots of water before exercising is just as important as during.
posted by gueneverey at 5:21 PM on June 4, 2007

Nthing what others said. Has happened to me several times either because I was doing something too strenuous, lack of oxygen, water or because of extreme heat (stayed in a sauna too long)

Regarding the loss of vision, thats why they call fainting "blacking out." You came close to it, it sounds like.
posted by vacapinta at 6:04 PM on June 4, 2007

Sorry, to answer the question more specifically with my huge physiology 201 knowledge base...

1. Vision is the first sense to drop when the brain is deprived of oxygen or glucose. The brain only functions on glucose and is not able to derive energy from lipids or proteins. Had your blood sugar level been lower you, probably would have just passed out. I don't know specifically what was happening in your brain but it was beginning to shut down.

2. It probably happened at the end of your workout (this is just a guess and a little out of my depth) because your muscle were shifting back from an aerobic state to an anaerobic state and the glycogen reserves just were not there.

3. The likely cause of all this was that from years of inactivity, the glycogen reserves in your muscles and liver were too small to keep up with the level or exercise you were doing and were depleted.

The water had nothing to do with it. When you swallow water the only thing it does is sit in your stomach until it exits your stomach 20+ minutes later. It isn't absorbed until it reaches the small intestine.

Chances are, in a few weeks when your body gets used to the increased load you're putting on it, none of this will happen again. However, you should definitely see a doctor about your symptoms because somewhat similar things can happen during exercise and be related to diabetes.
posted by 517 at 6:28 PM on June 4, 2007 [1 favorite]

If you come close to passing out while exerting yourself, it is usually one of those things. Normally, you'll become physically ill if you are pushing yourself too hard and then pass out, not pass out first. It might be a rapid transition, but the transition should be there.

Eat more before you work out, make sure you are hydrated, and for the love of god, make sure you are breathing while exercising. If you are just getting light-headed and almost passing out, it is probably one of those things.

If it happens again and you took care of those three things, see a doctor!
posted by Loto at 6:29 PM on June 4, 2007

Also, I'm not a doctor/trainer, but I have a lot of experience with getting ill or almost passing out after exercising :P
posted by Loto at 6:30 PM on June 4, 2007

As an aside, if dehydration is at all connected to this problem, then orange - or any - juice is probably a bad idea. The sugars therein are diuretics and drinking any sort of high-sugar beverage (OJ, soda, Gatorade, etc.) can make you less hydrated than you were before you had it.

My solution is to make my own: mix water, a soluble electrolyte supplement, and then some fruit concentrate and artificial sweetener to taste. Anything you drink for the electrolytes to aid in hydration will have those effects severely mitigated if there is much sugar in it, as well.
posted by ChasFile at 7:15 PM on June 4, 2007

As someone whos spent ALOT of time on an indoor rower (Concept 2 ergometer) its often that these symptoms are felt to a degree after a VERY hard intense workout. The rower stresses your cardio and muscle systems to the max and often you still feel the effects for sometime after the session. I would scale back on the rower until I checked in with a doctor and maybe worked on some lighter cardio work (power walking, light jogging, etc)

Congrats on heading back to the gym!
posted by crewshell at 7:37 PM on June 4, 2007

IANAD, but having frequently experienced exercise hypoglycemia, I second infinitewindow's suggestion about taking a snack or juice with you, and eating a meal an hour before the workout as well. Everyone who exercises should do this, but especially if you have a hypoglycemic event. Even if it never repeats, do not workout without carbohydrate snacks and plenty of water.
posted by BrotherCaine at 11:22 PM on June 4, 2007

This is nature's way of telling you, "Hey! Start out your exercise program a lot slower!"

Instead of going to the gym, you would be doing yourself a big favor to start by just going for a walk every day. When that feels comfortable (and no blackouts!) walk faster and farther. Take your own pulse rate and keep it below the red line. This will get you into shape to go back to the gym.
posted by exphysicist345 at 11:30 PM on June 4, 2007

Thanks everyone for the great answers!

I'm heading back to the gym later tonight for another session on the cardio machines. I'm going to have a light supper first, make sure I'm well hydrated before I start, and take longer breaks between finishing on one machine and starting on another (I'm not completely sure why I'm supposed to move from machine to machine, but if I see a trainer I'll ask). I'm going to make sure I drink sufficient water during the breaks, and if my body seems to be signalling that there's a problem I'm going to ease off the pace, and possibly take a brief spell on my back with my feet up.

I'm also going to make an appointment with the doc and ask if he can check my blood and the rest of me for anything abnormal that might produce the near-blackout episode I described. Until I hear what he says I'll hold off on doing anything fancy or heroic.
posted by Ritchie at 1:36 AM on June 5, 2007

Regarding the loss of vision, thats why they call fainting "blacking out." You came close to it, it sounds like.

First off - IANAD.
Your core temperature may have also been too high - this happens when overweight people (typically with lots of "insulation" and I am one of them...) exert themselves to the point of literally overheating. You may consider that the cold water you consumed lowered your temperature just enough to get your vision back.
I can personally attest to blacking out during exercise being a very, very scary experience.
posted by Carnage Asada at 4:32 PM on June 5, 2007