Have you felt faint or dizzy after a long or hard run? It’s not uncommon for runners to experience some light headedness when they stop running. It often happens at finish lines of races. Understanding what’s happening in the body can help you prevent any post run faintness.
When you’re pushing hard during a run your muscles are screaming out for oxygen. There are also waste products from exercise that need to be taken away. The body has huge capacity to bring extra blood to muscles during activity. Not only does the heart pump the blood faster and more forcefully but the blood vessels open up a little to increase blood flow. As you get fitter, your body even grows new tiny blood vessels (capillaries) to serve the extra demands of your muscles. Blood is diverted away from other parts of the body to maximise muscle blood flow – there’s a whole lot of blood in your muscles when you’re running.
When you cross the finish line and stop running, that increased blood volume pools in your legs. Your calf muscles are no longer acting as a pump to send blood back up to the heart. Gravity also plays its part too. As a result your blood pressure can drop and this makes you feel faint. You may start to feel dizzy, see stars or begin to stagger. If you don’t take action you may actually faint.
What to do if you feel dizzy after a run
If this happens to you, do the following:
- Lie down on the ground
- Tell someone nearby that you don’t feel well
- Raise your legs above the level of your heart (use a wall, railing or ask a friend to hold them up for you)
- Alternatively, sit crouched with your head between your knees
- Have a drink – preferably something with electrolytes and carbohydrates in case low blood sugar or dehydration is contributing to your faintness
- Stay in this position for about ten minutes
- When you feel better, move to a sitting position
- Once you are OK sitting then stand up slowly
- Continue to drink plenty and take it easy.
How to prevent post-run faintness
It can be quite disconcerting when you feel faint and you can get some unwanted attention when you lie down on the ground! It’s better to try to prevent it happening in the first place. There’s one simple thing you can do to reduce the chances of feeling faint after a run:
Don’t stop running abruptly. Even when you’re exhausted crossing the line. Have a cool down jog or brisk walk for five to ten minutes. Just keep moving. Let your body slowly adjust to the reduced intensity.
You can also help yourself by arriving at the finish line in good shape:
- Fuel your runs well so you don’t experience a dip in blood sugar
- Hydrate adequately, especially on longer runs and hot days
- Train properly. Be prepared and practised for the distance you are racing.
Remember that this post is about simply feeling light headed when you’ve crossed the line. Dizziness experienced during a run or dizziness that’s accompanied by other symptoms such as chest pain, palpitations or shortness of breath requires urgent medical attention. You can read more about these topics in my best-selling book Run Well: Essential health questions and answers for runners published by Bloomsbury and available from all good book sellers.