The Exercise and Insulin Resistance Connection

exercise and insulin resistance

I recently wore a continuous glucose monitor and discovered I have insulin resistance, a condition when the cells in your muscles, fat, and liver stop responding to the hormone insulin as they should. As an active person, I wanted to learn more about the connection between insulin resistance and exercise and if my struggle to maintain a healthy weight was related. 

You might think of insulin resistance as prediabetes, but they are very different. Prediabetes and diabetes occur when the pancreas doesn’t produce enough insulin to keep your blood glucose levels in a normal range. Insulin resistance occurs when your cells cannot use insulin, leaving more glucose in your bloodstream than is needed for energy. The excess glucose gets stored as fat in your abdomen area. 

Several studies show that you can reverse diabetes due to insulin resistance through physical activity.[1] In fact, exercise and insulin resistance share a very beneficial relationship. I will tell you more about the connection between exercise and insulin resistance, what exercises are best for insulin resistance, and how exercise can reverse the effects of insulin resistance. First, let’s talk more about insulin resistance. 

exercise and insulin resistance

What is Insulin Resistance?

When functioning optimally, your body’s insulin response operates this way:  

  1. When you eat food, your body breaks down carbohydrates into glucose for energy. Your body prefers glucose for energy over protein and fat because glucose is readily available and used for short bursts of energy. 
  2. Once the carbohydrate gets turned into glucose, it enters your bloodstream. This signals the pancreas to release insulin to control how much glucose gets in your bloodstream. 
  3. Insulin guides the glucose in your blood to enter your muscles, fat, and liver cells to use what it needs and store the rest for later. 
  4. When glucose enters the cells and your blood sugar decreases, your body tells your pancreas to stop producing insulin. 

For many reasons, such as a family history of type 2 diabetes, being overweight, and living a sedentary lifestyle, your cells cannot respond appropriately to insulin. When your cells can’t respond to insulin, your pancreas makes more insulin to overcome increasing blood glucose levels.[2]

Elevated insulin levels can result in weight gain, making insulin resistance more severe. In addition to weight gain. Insulin resistance is associated with high triglycerides, hardening of the arteries, and high blood pressure. 

Insulin resistance is also the main symptom of metabolic syndrome, which leads to fat buildup around the waist. 

Symptoms of Insulin Resistance

Even if you are not overweight, you can still have insulin resistance. If you have insulin resistance and your pancreas can produce enough insulin to keep blood sugar levels in the range, you won’t have any symptoms.[3] Very often, people with insulin resistance show no symptoms at all. It’s usually discovered during an annual exam or routine blood tests. 

However, some signs could indicate insulin resistance, including:[4]

  • A waistline of 40 inches in men and 35 inches in women
  • Blood pressure of 130/80 or higher
  • A fasting glucose level of 100 mg/dL or higher
  • An A1C of 5.7% to 6.3%
  • Fasting triglycerides level over 150 mg/dL 
  • HDL cholesterol level over 40 mg/dL in men and 50 mg/dL in women

Talk to your doctor if you believe you have insulin resistance and ask them to order a blood test. 

Over time, the cells of your pancreas that produce insulin become overworked, and insulin production slows or stops altogether. When this happens, you can develop prediabetes, which remains invisible until it develops into type 2 diabetes. The good news is that exercise can reverse insulin resistance. Before we discuss that, let’s talk about insulin’s role in exercise.  

Insulin Production During Exercise

Insulin sensitivity increases during physical activity. This happens so that your cells can use any available insulin to transport glucose during and after your workout. However, your body doesn’t need insulin during exercise to use glucose. When your muscles contract while you are working out, your cells can take up glucose and use it for energy whether or not there’s insulin in your bloodstream.[5]

In fact, low-impact exercise and strength training decreases insulin production by the pancreas. However, moderate- to high-intensity exercise increases insulin secretion to adjust for muscle resistance to insulin.[6]

Regardless, cortisol levels spike during high-intensity exercise. One role cortisol plays during exercise is inhibiting insulin secretion and stimulating glycogen release for energy, and this causes a temporary spike in blood glucose levels during exercise.[7]

Insulin’s role happens after you’ve stopped exercising.[8] Due to the high glucose levels in your bloodstream during exercise, your pancreas senses the need for insulin. It begins production once cortisol levels return to normal during the cool-down period. Even if you have insulin resistance, your body’s sensitivity to insulin increases for 16 hours post-activity.

So, what does that mean? It means that exercise improves your body’s insulin response and reduces the effects of insulin resistance, thereby lowering your risk of developing prediabetes or type 2 diabetes.

How Exercise Improves Insulin Resistance

According to a study, physical activity and exercise can not only prevent the development of type 2 diabetes; it can possibly reverse diabetes and insulin resistance. So, how does this happen?

Exercise reduces insulin in a couple of ways. First, low- to moderate-intensity exercise forces the muscles to utilize glucose from the bloodstream, clearing out the excess glucose that your body would typically store as fat. 

Regular exercise increases insulin sensitivity and reduces levels of A1C– glycated hemoglobins, or red blood cells coated in sugar.

  • A normal A1C range is 4.8 to 5.4 mg/dL or less.
  • Prediabetes levels range from 5.7 to 6.4 mg/dL.
  • Anything higher than 6.5 mg/dL is considered type 2 diabetes. 

Talk to your doctor about testing A1C levels. You can purchase at-home diabetes tests from companies like LetsGetChecked ($89) and Everlywell ($49)  and review the results with your doctor.

As I mentioned earlier, high-intensity workouts temporarily increase blood glucose levels due to high cortisol levels. However, once you’ve completed the workout, your body utilizes the glucose. Increasing muscle mass improves your body’s ability to utilize glucose and reverse insulin resistance. You should incorporate more resistance training into your workout routine to optimize your body’s insulin sensitivity. 

Exercise for Insulin Resistance

Any type of exercise can be beneficial, yet what the right amount is in regard to exercise and insulin resistance? The American College of Sports Medicine outlines the following recommendations:[9]

  • Cardio – 3 to 7 days per week for a total of 150 minutes at a moderate-to-vigorous intensity with no more than two consecutive days without activity. This includes a HIIT class, running, swimming, or brisk walking. 
  • Resistance training 2 to 3 nonconsecutive days per week at a moderate to vigorous intensity; 8 to 10 exercises performed for up to three sets of 10 to 15 repetitions to near fatigue per set involving major muscle groups. 
  • Flexibility and balance training– 2 to 3 days a week of stretching to a point of tightness or slight discomfort; light-to-moderate intensity balance exercises. This includes Pilates, TRX, and yoga. 

There are several opinions on what exercise is best for reversing insulin resistance. One study suggests that HIIT can reduce insulin resistance for up to 48 hours.[10] However, several studies show that 8 weeks of regular exercise can restore healthy insulin activity, which improves metabolism and reduces cravings.[11] Yet, you can exercise all you want, but it won’t do any good if you aren’t focusing on your diet. 

Diet for Insulin Resistance

As a sports nutritionist, I advocate for eating a diet of fresh whole foods and ditching processed foods with added sugars, preservatives, and additives. Buying all organic food can be expensive, so at the very least, ensure your protein comes from organic animal sources. 

Leafy greens, such as spinach and kale, are rich in potassium, antioxidants, and vitamins A, B, C, and K. Red vegetables, including red peppers, tomatoes, red cabbage, beets, and radishes, contribute phytonutrients, which contain antioxidants that can improve insulin resistance. 

Fruits such as berries, apples, pears, and peaches are also great foods for insulin resistance. However, some fruits like watermelon, pineapple, oranges, and bananas contain high amounts of natural sugar. They are fine in moderation. 

Organic meats such as wild-caught fish, free-range chicken and turkey, grass-fed beef, pork, and lamb are high in protein, which helps your body build and maintain muscle mass. How much protein you need depends on your activity level. The higher the activity level, the more protein you need. The other good part is that protein reduces sugar cravings. 

And don’t forget fats. Your body needs fat for energy, nutrient absorption, and hormone production. Avoid industrial oils such as vegetable, canola, corn, and butter. Stick with extra virgin olive oil, coconut oil, avocado oil, and plant-based butter. 

You should also avoid sugary energy drinks, soda, artificial sweeteners, and alcohol. All of these foods can increase blood glucose levels and your risk of developing insulin resistance or diabetes. 

Final Thoughts on Exercise and Insulin Resistance

Insulin plays a vital role in our body’s ability to use glucose for energy. When your cells become resistant to insulin, it forces your pancreas to work harder. Eventually, it becomes tired and stops producing insulin, which leads to the development of type 2 diabetes. If you are unsure how to utilize exercise and optimize your diet to help promote a healthy insulin response, let me help. Schedule a free discovery call, 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.