Nausea is a feeling everyone dreads. 

You’ve almost certainly experienced that queasy, uneasy feeling at one time or another — perhaps while standing at the start line of a big race… or even out of the blue on one of your weekly routine easy runs… maybe you’ve even experienced it after your run when you’re already finished…

According to The Cleveland Clinic, when you feel nauseous, you experience an uneasy feeling in your stomach that means you might have to vomit.

Let’s have a look at what nausea feels like in a bit more detail, why you may be experiencing it while you run, and what you can do to prevent it…

What Nausea Feels Like

Nausea can feel like a sudden urge to vomit or a low-level sense of discomfort and dizziness.

Nausea feels slightly different to everyone.

Symptoms Of Nausea According To Stanford Health Care:

  • Feeling like you are about to vomit
  • Lack of appetite
  • Profuse sweating
  • Repeated rhythmic contractions of respiratory and abdominal muscles that happen without your control (retching)
  • Stomach ache
  • An uneasy feeling in your chest, upper abdomen, or back of your throat
  • Vomiting

Now that we know how it feels, here’s what may cause these horrible symptoms…

Causes Of Nausea Before, During & After a Run

Pre-race nausea is quite common, it’s caused by the feeling of nerves and anxiety because of the high-pressure situation you find yourself in.

This same anxiety and nerves can be experienced by some in a normal training session too… 

Anxiety is a physiological and psychological state that is typically related to situations perceived as uncontrollable or unavoidable. 

Runners may feel these nerves before a race due to internal and external pressure they have placed on themselves. 

In short, physically, what’s happening to your body at that moment is a result of the anxiety, your body releases adrenaline, which disrupts your digestive system… resulting in the feeling of the need to vomit.

The most likely cause of nausea during your run is dehydration…

Maintaining proper hydration is essential to overall good health. Without water, your cells can’t function.

Other causes of nausea during a run may be if you consume too much salt in your diet, this makes you dehydrated and may make you feel nauseous.

Beginning or ending your run too abruptly without warming up or cooling down may lead to the feeling of nausea.

Nausea could also happen because blood flowing to our gastrointestinal tract and stomach is rerouted to the muscles we’re working on, thus slowing digestion and causing discomfort.

If you’re running in hot weather then you’re probably going to start sweating quite quickly… this is a great way to detox but can also cause dehydration and low blood pressure… which can lead to nausea and most times, vomiting. 

Another common cause for feeling nauseous after a run is when you try to push yourself just a bit too hard and run at too high of an intensity.

5 Reliable Ways To Prevent Nausea Before a Run

  1. Leave 2 hours between your run and your pre-run meal… Rather have a pre-run snack just before you run.
  2. Take extra care with your pre-race meal. (consider a liquid pre-race meal, which is digested quickly, as opposed to more solid foods.)
  3. Warm-up properly. This will relieve a lot of anxiety.
  4. Do a reality check. (Why am I here?)
  5. Visualize your success.

 5 Reliable Ways To Prevent Nausea During a Run

  1. Prevent anxiety by focusing on the things you do have control over.
  2. Run at the correct intensity.
  3. If you take gels, make sure you take them with water and not another carbohydrate drink.
  4. Avoid taking anti-inflammatory drugs like ibuprofen around your race. Research has associated these with vomiting during endurance events.
  5. Make sure that you are adequately hydrated and that you sip water when you’re thirsty.

5 Reliable Ways To Prevent Nausea After a Run

  1. Avoid eating something too heavy and rich before your run
  2. Stay well-hydrated before and during your run to avoid dehydration.
  3. If you are consuming sugary foods during the race, make sure to ingest them with water to aid in digestion.
  4. Immediately stopping after your last interval or once you’ve crossed the finish line can wreak havoc on your stomach because it’s not prepared for the rapid change in exertion so remember to do a cool-down walk or run.
  5. Use caution when the weather conditions are extremely hot and humid.

Now that we know how to prevent nausea before, during, or after a run… Let’s have a look at a few other nausea-related situations runners may experience. 

How To Prevent Runner’s Stomach/ Belly

Runner’s belly is common. It is estimated that between 30% to 90% of runners and endurance sport athletes experience Gastrointestinal Complaints during training and races. 

When you’re running for an extended period, the blood flow that’s normally directed to your digestive system is diverted to your cardiovascular system.

This can disrupt your digestive process. Resulting in the strong urge to expel whatever is in your digestive system… which could lead to diarrhea symptoms and nausea. 

A more common name for runners belly is runners trots which is characterized by frequent, loose bowel movements. 

5 Ways To Prevent Runners Trots:

  1. Aim to eat your last full meal 2 hours before your run to minimize your chances of Gastrointestinal distress.
  2. Adequate hydration before and during a run can help minimize your risk.
  3. Optimizing gut health is one of the best ways to prevent runner’s stomach.
  4. Chat to a professional about considering taking supplements
  5. Book your consultation with Coach Parry’s nutritionist Nicki.

Reasons & Preventions For Nausea On a Long Run

The causes of why you may experience nausea on a long run can range from things as wide as the onset of hospital serious in other words you’ve been running for a long time and you haven’t been providing your body with any energy and that can lead to people feeling nauseous.

Similarly, if you’ve been taking in too much sugar in particular in the form of things like gels which are a very concentrated form of sugar, and then you’re not taking enough fluids, you can become very dehydrated.

Generally, in longer events where people feel nausea, they tend to abuse anti-inflammatories and pain killers… which exacerbate nausea.

Another common cause of nausea on long runs is overhydration…, water intoxication, which is much more dangerous than dehydration.

People who suffer from nausea become a little bit of an ongoing experiment, you’ve gotta try various things.

Prevention Of Nausea On Long Runs:

This is probably one area worth experimenting with Ketosis, maybe using ketone gels and ketone products that you can use throughout your run.

For some people, it’s as simple as finding a way of using solids…

We’ve had a client that struggled with nausea for a long long time and she ended up experimenting with something very similar to a Chelsea Bun and that worked for her… she has no more nausea issues. Since then she eats Chelsea Buns periodically.

Other solids you can try are nut butter, cashew nuts, macadamia nuts, dates and you can also experiment with MCT oils and Ketone oils.

Note: If you’ve experimented quite a bit and it’s something that just continues to persist then you should go and see a sports physician and do a couple of tests to make sure there isn’t something specific to you from a medical point view. 

Combating Nausea Ahead Of The Comrades Marathon


Devlin Eyden has a passion for seeing his athletes grow and excel. From novice runners or cyclists across all disciplines to elite mountain bikers representing South Africa at World Championships. In addition to helping you ride faster, for longer, Devlin also has the personal touch when it comes to your bike setup, aiming at improving the overall rider experience. With his background as a Sport Scientist as well as a Strength & Conditioning specialist, performance is Devlin’s main priority, be it in the gym, the lab or out on the road or trails. Being a keen runner & cyclist and having completed the Cape Epic among others, Devlin has first hand experience in what it take to reach your goals. If you’re looking for a once-off training program or ongoing, high touch support Devlin has you covered.

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