Lightheadedness After Exercise

Speak to a real fitness fanatic and often they will tell you how much they love the feeling they get after working out. They might talk about ‘the pump’, about the ‘burn’, about endorphins, about ‘the runners’ high’ and generally they will tend to sound insanely enthusiastic (I should know, I’m one of them). So why is it then, you may wonder, that when you work out you tend to just feel tired, worn out and sweaty? Worse still, where does that lightheadedness come from?

Well while I’m not fanatical enough to tell you that being lightheaded is a good thing, or particularly pleasant, what I can tell you is that it’s not particularly bad for you either and that you should be perfectly fine even if you do feel a little woozy after you train (though in some cases you might want to get it checked out). Read on to find out what’s causing it and how to get back to normal.

Lack of Energy

Our body runs on one type of energy and that’s ATP which is harvested from the sugar (glucose) in our diet. That’s what we use when we blink, what we use when we run and what we use when we exercise. It’s also what we use in order to think though, and this means that if you use up all the blood sugar in your body exercising you can end up leaving little left in the blood for your brain to run on – which in turn leaves you feeling a little dizzy.

The solution then is to make sure to top yourself up with good fuel during and after your workout. If you are feeling lightheaded then one of the best things to consume after training to get you back to normal is an ‘isotonic’ energy drink which is designed to contain the same amounts of salt and sugar proportionate to that found in the blood. It’s also important not to eat simple carbs right before exercise which result in an insulin spike followed by low blood sugar – rather you should eat ‘complex’ (slow release) carbs like bread or pasta an hour or so prior to training.

If this is a problem that you have repeatedly and you find yourself shaking after small amounts of exercise, then you may have chronic low blood sugar and you should consult a doctor for more information.

Lack of Salt

Sugar isn’t all you lose when you work out – you also lose a lot of salt which you sweat out through your pores to keep your body temperature cool. That salt is an electrolyte and it’s something that your body uses to send chemical signals between nerves – including the brain cells. Again then you want to try and replenish this salt as quickly as possible and one of the best ways to do that is by again using a sports drink.

Lack of Oxygen

During a workout we need to get more oxygen to our muscles and organs than normal, and at the same time we find ourselves tensing our chest and abs which can make breathing hard. If you find yourself holding your breath while you push through that last bench press then there is a very real chance that this will be leading to your feelings of dizziness. Practice getting your breathing into a rhythm with your running/lifting and you’ll get more from your workouts.

Low Blood Pressure

We can feel lightheaded if our circulatory system isn’t getting enough oxygen to our brain, and this can happen to us following exercise due to something called vasodilation. Here what happens is that the brain realises more oxygen and blood to your muscles and so it widens the blood vessels (dilation) and increases your heart rate (this is why your veins protrude when you’re working out too). The only potential problem is that when you slow down again and your heart rate drops back to normal, your blood vessels might take a second to catch up which then means the blood doesn’t get around as easily (just as you need to suck harder to get water through a larger straw). One solution is to use a vasoconstrictor like caffeine to constrict the vessels down again – though this isn’t a great idea as having dilated veins and arteries helps the body to build muscle and repair damage.

Blood pressure of course varies between individuals and is based on numerous factors. If you suspect you have chronically low blood pressure, then it may be advisable to again see a doctor.


Certain medications can leave you feeling dizzy, and particularly after exercise which causes you to metabolise them more quickly. If you suspect that medications may be making you feel feint after training then consult with your doctor.


During exercise we tend to throw ourselves around all over the place and even sometimes flip upside down or roll over our body. This then can leave us struggling to find which way is up and which is down as our brain tries to make heads and tails of the information coming from our eyes and our vestibular system. If you struggle more than most then this may be due to a balance disorder, though in most cases it just means you need to take it a little slower.

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