WEIGHT MANAGEMENT ∙ 4 minute read

Why working out can make you feel sick

By Luke Chapman | Medically reviewed by Lauren Sien

Nausea. Sickness. Vomiting. Whatever you call it, you know the feeling. It’s the retching sensation in your stomach after a spin class or the gagging feeling after a 5k. It’s grim. 

But why does it happen?

There are actually many reasons, ranging from your diet to your lifestyle. Let’s take a look:

1. Hydration

You can become nauseous due to drinking too much or too little water. It’s all about balance. Improper fluid intake before exercise can cause exercise-induced vomiting, even in healthy athletes

Conversely, you can feel sick after drinking too much water. Overhydration impacts your electrolyte levels and sodium concentration, which leads to nausea. Stocking up on electrolyte drinks is an easy way to replenish after a workout. If you’re someone who gets to the gym and realises you’ve forgotten your water bottle, pack it the night before. As the old saying goes, fail to prepare, prepare to fail.

2. Nutrition

It’s all about what you eat and when. 3-4 hours before your meal, you need to load up on carbs. Smash through a hearty bowl of pasta or rustle up something rice-based. It’s the fuel you need to sustain a worthwhile workout. Anything under two hours, you need energy. Think cereal bars, fruit, or light snacks – sometimes the burst of energy can be the difference between an average and intense session.

It’s equally important to eat immediately after strenuous exercise. Aim for 0.65 grams of carbohydrates per pound of body weight within 30 minutes of exercise. If you can’t get the exact food you need, still eat something. You need food in you.

3. Intensity

You want to go hard. You want to make the most of your time in the gym, on the court, or on the exercise bike. Otherwise, what’s the point? 

But don’t overdo it.

Too much exercise can cause damage to your body. When you’re feeling ill after a workout, you might have pushed past your limits. Reign it back next time. 

How much should I exercise per day?

Experts recommend moderate to intense exercise most days of the week. That means you can miss a day. Don’t stress if you didn’t make your morning yoga class or snoozed the alarm instead of hitting the weights. It’s healthy to have rest days. 

If you’re starting to feel guilty for missing a session or you’ve stopped enjoying it, stop. Give yourself a break and regroup. It’ll benefit you in the long-term. Once you’ve recharged, get back exercising and make it count.

When is the best time to exercise?

It depends on your goals. If you’re focussed on performance levels, the best time to exercise is in the evening. You’re more likely to have eaten one or two meals, which fuels the body for an intense workout. 

If you’re looking to burn fat, you’re better off exercising in the morning because you haven’t eaten. Your body is forced to draw energy from stored fat reserves, amplifying the fat-burning process. 

Should you exercise when you’re not feeling well?

The decision point lies in the neck. The general rule is that most illnesses above the neck should mean you’re alright to persevere. That means you can power through with a head cold. Keep running with a congested nose. You’ll be fine. 

Below the neck, it’s time to stop. Have a rest with chest congestion or take it easy with an upset stomach. If it’s below the neck, any exercise typically just makes you feel worse and prolongs the time that you’re ill. Be sensible and have a break. 

Workouts that don’t cause nausea

Prevention is easier than cure. Instead of combating the effects of exercise-induced nausea, adopt a more manageable workout. Make sure you start at a slower pace and don’t end too abruptly. Feel free to push yourself in the middle – it’s the start and finish where nausea can appear. 

If you’ve eaten prior to working out, avoid exercises that bounce the body around. Replace pilates with indoor cycling or swap steep hills for the treadmill.

The numan take

Exercise-induced nausea is something that often seems inevitable, but it’s not. Ranging from nutrition to hydration, there are plenty of ways to avoid that sick feeling. Everything lies in your preparation. Before you exercise, make sure you have the right amount of water and food in you. Then go at it.