Can Exercise Damage Your Gut?

can exercise damage your gut

We all know that exercise is good for you. Exercise helps keep off the extra pounds, reduces the risk of disease, helps regulates your blood sugar, and improves your mental health. Yet, can exercise damage your gut?

You may not have expected to hear that. Still, if you are overdoing it in the gym, your gut becomes vulnerable to increased intestinal permeability and dysbiosis, an imbalance of good and bad bacteria in your gut microbiome. Moreover, too much exercise can weaken your immune system.[1]

This doesn’t mean you have to give up your daily workout routine. However, you might want to cut back if you do more than 60 minutes of moderate- to high-intensity exercise daily. If you’re worried, don’t be. I will explain to you how too much exercise can harm your gut and how you can protect your gut health while engaging in high-intensity activity. First, let’s talk about your body’s response to exercise. 

Exercise is Stress on Your Body

To understand how exercise can damage your gut, you must understand how your body responds– both during and after exercise. 

When you start warming up to work out, your central nervous system recognizes this and triggers your “fight or flight” response. It’s the same way your body responds to stressful situations, such as financial problems, tight deadlines, relationship problems, or being stuck in traffic. 

Your central nervous system tells the hypothalamus in your brain that it’s about to be in danger. The hypothalamus then signals your pituitary gland to release hormones and tells your adrenal glands to release cortisol, the stress hormone.[2]

Meanwhile, your pituitary gland is also releasing human growth hormone and prolactin. The pituitary hormones signal your sex glands (testicles in men and ovaries in women) to release testosterone. 

This hormone response causes insulin levels to reduce, which causes spikes in your blood sugar while you’re exercising because your body uses most of your stored muscle glycogen (glucose stored in your liver and muscles) for energy during high-intensity exercise.[3]

In response to these hormones, your body releases serotonin, dopamine, and endorphins during exercise. These mood-boosting hormones provide essential benefits to your body during exercise. Serotonin helps lower cortisol levels, while endorphins signal the release of dopamine and attach it to the neurotransmitters in your brain that cause you to feel pain.[4] This is why you don’t feel sore right after exercising. So, how is all this connected to your gut health? Well, it starts with cortisol.

Cortisol and Your Body

Cortisol is a steroid hormone that aids growth, development, and sexual health. Nearly every cell in your body has receptors for cortisol, which has many functions in your body. Cortisol is essential for regulating blood glucose levels, blood pressure, inflammation, electrolyte balance, and metabolism.[5] However, cortisol’s primary job is to respond to stress. 

Occasional stress is normal and not harmful to your body. However, if your stress response never turns off, cortisol levels stay elevated in the bloodstream, which can negatively affect your entire body. Some signs of high cortisol levels include:[6]

  • Increased blood sugar
  • Weight gain and rounding of your face
  • Easy bruising
  • Muscle weakness
  • Severe fatigue
  • High blood pressure
  • Headache 
  • Difficulty concentrating
  • Slowed healing
  • Low sex drive
  • Acne

Moreover, too much cortisol suppresses your immune system. It can damage your gut health by increasing permeability and limiting oxygen-carrying red blood cells flow to your stomach, leading to irritable bowel syndrome, ulcers, and irritable bowel disease. 

If you excessively exercise, cortisol levels stay elevated in your body in response to the stress from working out and make your gut vulnerable to infection. 

Cortisol and Your Gut

If you exercise excessively by working out more than 60 minutes daily or not taking rest days, your cortisol levels are likely off the charts. This is hard on your digestive system and your immune system. Nearly 80% of your immune system lives in your gut.[7] If your gut isn’t healthy, your immune system isn’t healthy. 

Cortisol aids in moving blood flow toward your brain, large muscles, arms, and legs, and away from your gut. The lack of oxygen-filled red blood cells leaves your gut microbiome vulnerable to harmful bacteria, which multiply without good bacteria to keep your microbiome in balance. This causes dysbiosis, and harmful bacteria, fungi, and parasites take over your gut.

Moreover, elevated cortisol levels make it harder for your immune system to fight off bad bacteria and viruses, leading to intestinal permeability and increased inflammation. Here’s what happens: 

Your intestinal wall has small channels that allow micronutrients from your food to travel to your bloodstream, which delivers the vitamins and minerals to your cells. Cortisol breaks these channels apart and makes them wider. Once this happens, microbes and undigested food particles escape into your bloodstream. Your immune system identifies these as foreign invaders and begins to attack them, increasing inflammation in your body. 

Suppose you have chronic stress from a high-demanding job, an abusive relationship, or a life-changing event. In that case, your cortisol levels are constantly elevated if you aren’t taking measures to reduce stress. By excessively exercising on top of your chronic stress, your cortisol levels are likely off the charts. Let’s talk about what defines “too much exercise.” 

What is Too Much Exercise?

Exercise has many benefits, but you can take it too far. No magic number of minutes determines how much exercise is too much. It depends on many factors, such as age, weight, medical history, and fitness level. 

But current research demonstrates that too much exercise may cause harmful effects known as overtraining syndrome, which often occurs in athletes, fitness enthusiasts, or people struggling with an eating disorder. If you’re not giving your body the time it needs to recover, some harmful side effects go beyond joint pain or muscle fatigue. 

These side effects include hormone imbalances, mood disturbances, poor sleeping patterns, reproductive disorders, and an increased risk of intestinal permeability and dysbiosis. 

According to the Physical Activity Guidelines for Americans, adults need 150 minutes of moderate- to high-intensity exercise and two days of strengthening activity per week. Moderate-intensity training includes running, aerobic exercise, cycling, swimming, or playing tennis or another team sport. 

Too much exercise can make you feel tired and increase feelings of depression, and it can affect your sleep patterns and your appetite. Not to mention, too much exercise elevates cortisol levels and causes an array of digestive problems.

A best practice is to set aside one day to rest and recover with no exercise. If you are engaging in high-intensity exercise regularly, you want to take a few steps to care for your gut. One of those is to reduce stress. Let’s talk about ways to reduce stress. 

Natural Ways to Reduce Stress

Understand that stress is not the same as anxiety and depression. Talk to a medical professional if you believe you have anxiety or depression. Here are five ways to reduce stress: 

1. Exercise

There’s a difference between overdoing it and getting regular exercise. Moving your body is excellent for improving mood, reducing stress, and regulating sleep patterns. If you aren’t currently active, start with gentle activities such as walking for 30 minutes or riding a bike. Choose something you enjoy doing to increase your chances of sticking with it. 

2. Eat A Healthy Diet

Not only does what you eat affect your gut health, but it also affects your mental health. Chronic stress increases your sugar cravings. Processed sugar leads to high glucose levels, which causes weight gain. It also elevates cortisol levels. Eating a diet full of nutrient-dense whole foods and taking a multivitamin will give you nutrients essential for reducing stress, such as magnesium and B vitamins.[8]

3. Consider Supplements

Ashwagandha, B vitamins, and Rhodiola have been shown to help reduce stress. An 8-week study of 264 people found that taking 300 mg of magnesium daily helped reduce stress levels. Combining this dose of magnesium with vitamin B6 was even more effective.[9]

4. Reduce Caffeine

Caffeine can increase feelings of anxiety, not to mention disrupt your sleep patterns. Poor sleep can increase cortisol levels. Your daily caffeine consumption should be under 400 mg per day. That’s about 4 to 5 cups of coffee.[10]

5. Spend Time with Your Pet

Petting a dog or cat, or cuddling with your pet, releases oxytocin – one of your four happy hormones. Pets add to your life satisfaction and increase your self-esteem. Having a dog or a cat gives you purpose and reduces stress. 

There are plenty of ways you can reduce stress in your life. Aside from that, if you engage in high-intensity exercise regularly, you will want to take care of your gut. Let me tell you how.  

Caring for Your Gut

If you are engaging in regular high-intensity exercise, you need to take two supplements to care for your gut health: Collagen and L-Glutamine. 


Collagen is the most abundant protein in your body. A collagen powder should be part of your post-workout routine if you live an active lifestyle because of its robust benefits that support recovery from exercise. Here are four benefits of collagen for exercise:[11] 

  • It helps reduce joint inflammation
  • Improves muscle mass
  • Improves injury recovery time
  • Promotes weight loss
  • Contains eight of nine essential amino acids

More importantly, collagen is crucial in rebuilding and strengthening the gut lining damaged during excessive high-intensity exercise. The amino acids glycine and glutamine are essential for repairing the gut lining. This protein also aids in digestion and nutrient absorption. 

A high-quality hydrolyzed collagen powder containing type 1 and 3 collagen is easy to add to your diet. It’s unflavored and can be added to shakes, smoothies, and even your morning coffee. 


Glutamine is a source of energy for cells in the small intestine and helps rebuild the gut barrier by facilitating the reproduction of healthy cells. Because glutamine maintains the gut barrier, it also helps protect you from increased gut permeability. 

The benefits of glutamine don’t stop with gut health. Glutamine promotes muscle recovery,  boosts your immune system, and helps detoxify your liver.

Your body makes glutamine on its own, but if you’re active, it quickly depletes its natural sources. Adults who engage in high-intensity exercise should take 5,000 mg of glutamine daily.[12] Glutamine supplements come in a flavorless powder or in capsules. 

Taking care of your gut is so essential if you are engaging in any form of high-intensity exercise. You can do this by not overexercising, giving your body enough time to rest, and supplementing with collagen and L-glutamine. Exercise should make you feel better. If you’re overdoing it with high-intensity exercise, you leave your gut vulnerable, which will impact your immune system and negatively affect your health. 

If you want to learn how to optimize your workouts and diet to improve your health, set up a discovery call with me and let me help you get on the path of Living Very Well™.

About Michael
About Michael

Michael is a functional health coach and sports nutritionist based in Austin, Texas. He has a master's degree in kinesiology from the University of Texas and advanced certification in sports nutrition from the International Society of Sports Nutrition.