Q+A: Why do I feel nauseous after racing?

Our experts answer real-life questions

Posted: 9 September 2000
by Nick Critchley

Q I have a problem that seems to affect me after finishing half-marathons: I feel queasy and don’t want to eat or drink. The feeling seems to pass if I lie down for an hour or so. As advised, I always try to take on water at each drinks station. Do your have any idea why this happens?

A When you exercise hard there is increased bloodflow in the active tissues. For short exercises this affects your exercising muscle groups, but for longer bouts it travels to the large organs which are responsible for maintaining the body’s internal environment. The liver and the skin are two of the primary organs, but the stomach is also often affected, which can cause that knotted empty feeling that leaves you temporarily unable to eat or drink.

Some people also experience a mild hypoglycaemic reaction after prolonged exercise. The body’s energy-producing systems sometimes fail to keep pace with the demands placed on them, and blood-sugar levels fall low enough to make you feel faint, clammy and tight in the stomach. Palpitations and mild tremors are also not uncommon, but as blood-sugar levels return to normal the feeling usually passes.

Prevention is usually found in adequate pre-exercise nutrition and hydration, and the use of energy drinks while running instead of water. It may take bit of practice before you get an exact idea of how much to drink and eat. If this queasy feeling happens again, try taking on small amounts of sugary foods and regular small amounts of water until the feeling passes.

Nick Critchley, exercise physiologist with Medifit medical and fitness centres

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I ran the Gloucester 20 mile on Sunday 9th, was going along nicelly until mile 15 (2hrs 10ish) till then, when I started to get cramp in both calfs and both hamstrings. I've never got cramps before, had to stop a couple of time during the last 5 miles to get rid of the cramps. Managed to finish the race in 2:57:30. Also at the end of the race I felt sick, lightheaded, and generally unwell, again something I have never felt before. I took on water/sports dring before / during /after the race, the weather was nice, not to sunny.

Could may problems be caused by the same thing ? if so what is it, and what can I do to prevent them happening again.

Any help would be very grateful

Mikey Ev
Posted: 10/03/2003 at 10:47

Mikey, sounds like dehydration, it is difficult to drink enough on a run of that length and getting the balance right between drinking enough before you start and not having to pee all the time is really difficult.

I havn't looked at it myself yet but try this site for hydration info www.hydropt.com
Posted: 10/03/2003 at 11:27

Posted: 25/12/2004 at 17:39

Yes I think you can finish the London Marathon.
Posted: 26/12/2004 at 00:21

In the 2007 FLM I became nauseous at 7 miles after taking a Gel, and it continued all the way to the end, getting worse and worse. By the end I had chest pains and took myself off the medical tent.

I was also puzzled because after my three longest training runs I'd felt sick when I finished, and rough for the rest of the day.

Talking things through with my GP I've tried Lansoprazole, which are gastro-resitant capsules. The idea is that they inhibit too much stomach acid being created, because it looks like I have a reflux problem, and when I'm running long distances it creates the problems I suffered in London and my training. Presumably the acid splashes up instead of remaining in the stomach, and causes the pain/nausea. 

When I took a dose earlier this year it made a tremendous difference to some races I took part in, although a second supply seems to be having slightly less effect. I'll see how it goes.

Posted: 06/09/2007 at 15:04

I'm running London Marathon this year ... the last few years when i'[ve run longer distances (more than half marathon) I feel really sick at the finish. When I've had something to eat and a drink and rest for a while I'mm okay. I did Ashyby 20 on Sunday and had these sick feeling at around 16miles and felt sick for couple of hours afterwards .... any recommendations on what I should eat when and how much before a marathon .. because I think this feeling could be because I'm too hungry .... I do like my food

Posted: 20/03/2012 at 15:25

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