Exercise and digestion are mutually exclusive. When you exercise, your body isn’t using its energy for digestion. Instead, it slows any digestion currently taking place so it can divert as much blood as it can to feed your muscles and your lungs.
If you’ve just eaten before exercising, you can experience gastrointestinal problems. Depending on the type of food you’ve eaten and the intensity of your exercise program, you may suffer from heartburn, stomachache, or even vomiting. (See below for pre-exercise eating tips.)
For example, eating a complex meal that’s high in fiber, protein or fat before a high-intensity workout is not a good idea and likely will not end well. So if you only remember one thing from this article, remember that exercise time does not coincide with digestion time.
Gastrointestinal Benefits of Exercise
But that doesn’t mean you should give up exercising. A regular exercise regimen — along with a positive mental outlook and a healthy, high-fiber diet — are the building blocks of a healthy lifestyle. Exercise can relieve constipation and promote healthy digestion when you’re at rest.
Over time, regular exercise can strengthen your digestive tract. If you’re fit, the amount of blood diverted from your digestive system decreases because the need is less urgent. Your muscles are more efficient when you’re in shape.
Cautions When Exercising
Give your body the proper time to digest before exercising. If you eat a meal heavy in proteins and fats, you may need two or three hours for digestion. Your blood sugar rises to help you digest. Wait for it to drop back to normal, so you can devote all your energy to your workout.
A large meal, especially if it contains a lot of fat, can delay your digestion, which in turn should delay your exercise time. On the other hand, not eating anything before a workout will leave you feeling tired and weak. Unless it’s the day before a marathon, eat a balanced meal and give yourself time to digest before you exercise.
In addition, keep hydrated while you exercise. Dehydration is one of the leading causes of exercise-related gastrointestinal problems. It can lead to constipation, acid reflux, and even malnutrition when your intestines don’t absorb all the nutrients from the food in your system.
Runners in particular can be subject to bouts of diarrhea. It’s the combination of the physical jarring and the lack of blood to the intestines that cause the temporary condition. Avoid caffeine, dairy products and sugar substitutes before you exercise if you’re susceptible.
Pre-Exercise Eating Tips
- Ideally, eat about three hours before you exercise. Eat less if you dine less than two hours before your workout.
- Eat food you can digest easily, like those high in carbohydrates and low in fats. Bananas, toast and oats are excellent low-fiber carbohydrate sources.
- Avoid proteins and high-fiber foods, which digest more slowly.
- Keep yourself hydrated during your exercise regimen.
- When hydrating, take big gulps. The fluid leaves your stomach more quickly this way.
Contact NYC Gastroenterologist, Dr. Shawn Khodadadian to learn more about exercising and your digestive system.