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Does Stress Cause Insulin Resistance?

7 minutes read

More than half of Americans experience stress so extreme that they feel paralyzed [1]. An even higher number — 93% of Americans — experience chronic stress at work. Around the world, stress has risen in recent years — 44% of people in the EU report that stress in the workplace has increased since 2020, and in the UK, that number is 79% [2, 3].

While the signs and symptoms of stress can vary from person to person, chronic stress can take a serious toll on your emotional and physical health [4]. It’s linked to everything from poor sleep and unstable moods to hunger cravings and muscle pain. Over time, it can even disrupt your body’s ability to regulate glucose, promote insulin resistance, and trigger chronic inflammation [5]. These effects can slowly wreak havoc on every aspect of your health and even reduce your lifespan and quality of life [6].

But how exactly does stress affect your metabolic health, and what techniques can you use to manage stress levels on a day-to-day basis? Let’s dive in.

What is stress?

According to the World Health Organization, stress is “a state of worry or mental tension caused by a difficult situation” [7]. Put another way, it’s a feeling of strain or pressure related to work, relationships, and life — and a completely natural response to everyday challenges, whether physical or psychological in nature. While you’ll never completely eradicate stress from your life, the way you handle stress makes all the difference to your health.

What causes stress?

The feeling of stress is triggered by the hormone cortisol (a.k.a., the stress hormone). When your body is in a difficult situation, whether it’s physical (like a fire or car accident) or emotional (like a presentation or layoffs at work), your central nervous system prompts your adrenal glands to produce two hormones that push your body into a “fight-or-flight” state: cortisol and adrenaline [8].

You can think of adrenaline as slamming your foot on the gas to escape from a stressful situation, and cortisol as gently keeping your foot on the pedal to keep your car at a steady speed [9]. In other words, adrenaline is meant to get you out of an emergency as quickly as you can, while cortisol keeps your body in an alert state until all signs of danger have completely disappeared.

Acute stress vs. chronic stress

There are two types of stress — acute and chronic — and both have different effects on your health [10].

Acute stress is short-term — you experience it in specific, one-off situations. For our ancestors, this meant escaping from a predator or going on a hunt; in the present day, it may be a tight deadline or a first date.

Chronic stress is long-term, consistent, and often overwhelming. It can be triggered by poverty, a job you hate, the death of a loved one, or a dysfunctional family situation. Whereas the symptoms of acute stress come and go as your body brings your cortisol and adrenaline levels back down after a stressful event, chronic stress has no end in sight. In fact, it keeps your body stuck in a state of heightened cortisol and adrenaline, which can have immediate and long-term effects on metabolic health.

Acute stress is a healthy, short-term response to real or perceived threats, while chronic stress is an unhealthy, persistent response that can interfere with your ability to live your life normally.

Why is this important?

Chronic stress is linked to the leading causes of death, including heart disease, diabetes, and cancer [11]. It’s affecting more and more people every year — in 2022, 60% of people globally reported feeling at least one instance of stress that was so intense that they couldn’t cope or deal with their situation [12].

As our lives become increasingly more stressful, with 31% more Americans describing their mental health as only “fair” or “poor” at the start of 2023 compared to 2022, managing stress is one of the most important things you can do for your health [13].

How does stress affect insulin resistance and metabolic health?

Stress has a variety of symptoms (anxiousness, depression, aches, fatigue, sadness, weakened immunity) but it can also affect your metabolic health by promoting insulin resistance and increasing blood glucose levels [14]. It does this primarily through two mechanisms — the physiological and the behavioral — which act together to create a reinforcing cycle of increased stress, inflammation, and metabolic detriment.

How stress promotes insulin resistance on a cellular level

Chronic stress can promote insulin resistance and hyperglycemia (elevated glucose levels), as well as disrupt your body’s ability to regulate glucose [5]. This is because cortisol actually works in opposition to insulin, and when your cortisol levels are high, your cells become temporarily resistant to insulin.

But how exactly does this happen? One of cortisol’s primary functions is to ensure that your body has enough energy to make it through a stressful situation. When cortisol levels in your body rise, your liver releases glycogen (stored glucose) into the bloodstream to provide your cells with immediate fight-or-flight energy — leading to an increase in blood glucose levels.

This cues your pancreas to release insulin into your bloodstream to help bring those glucose levels back down. Insulin’s job is to help glucose enter your cells so it can be transformed into energy and to shuttle any leftover glucose to the liver so it can be stored as glycogen for later use.

But since your body wants to keep your circulating levels of glucose high during a stressful event — i.e., readily available to be converted into energy, and not stored as glycogen — cortisol and growth hormone (which is also released during a stressful event) actually make your tissues less sensitive to insulin [15].

Again, this is a natural biological response to stress and isn’t anything to be worried about in the event of acute stress. But over time (i.e., with chronic stress), this cortisol-induced insulin resistance can become long-term and have ramifications on other parts of your well-being.

In fact, a 2003 study found that prolonged high cortisol and psychological stress can actually lead to the death of beta cells (β-cells) in non-diabetic subjects [16]. Beta cells, which make up less than 1% of your total pancreatic mass, are responsible for producing insulin, and losing or damaging them can reduce insulin sensitivity and disrupt glucose regulation.

Another study in non-diabetic subjects performing a stressful task (bungee jumping) found that beta cell function decreased right before the jump and insulin resistance increased after the jump, suggesting a correlation between high cortisol levels and both insulin resistance and decreased beta cell function [17].

Research has also found that chronic stress can contribute to sustained low-grade inflammation [18]. Inflammation triggers the release of pro-inflammatory cytokines (signaling proteins) in your body, which have been shown to induce insulin resistance and elevate glucose levels. On top of that, insulin resistance itself is associated with greater production of pro-inflammatory cytokines, meaning that inflammation can spur a vicious, unending cycle of increased inflammation and increased insulin resistance [19]. If left unchecked, this can spiral into type 2 diabetes and other metabolic disorders.

The effects of stress on your appetite, cravings, and lifestyle

In addition to the physiological effects on your metabolic health, chronic stress can also affect your behavior. Research indicates that heightened cortisol levels can change the way your brain perceives food, leading to cravings for high-calorie (and often processed, sugary) foods, which can lead to extreme glucose spikes and crashes, inflammation, and weight gain — all of which may be amplified in the insulin-resistant state that cortisol naturally creates [20].

Another study found that when you eat sugary foods — particularly refined foods that are high in the simple sugar fructose — your body produces lower levels of insulin, lower levels of the hormone leptin (which suppresses appetite), and higher levels of the hormone ghrelin (which stimulates appetite), meaning that you’ll feel hungrier — which is why you may have heard of the term “stress eating” [21].

In addition to increasing your desire and appetite for unhealthy foods, stress can also make it more difficult for you to maintain a healthy lifestyle. One study performed on university students found that higher stress levels were associated with reduced physical activity, even though greater physical activity was associated with reduced stress [22]. This is supported by another small study in 2021, which found that stress increased participants’ desire for less demanding tasks and activities [23].

The takeaway? Chronic stress isn’t just a bad feeling — it has powerful effects on insulin sensitivity, glucose levels, and inflammation that can drive you into negative feedback loops. Over time, these feedback loops can lead to a cascade of poor metabolic health choices and habits like snacking, cravings for unhealthy foods, and less movement — all of which which only keep you trapped in a state of metabolic dysregulation.

Is there such a thing as “good” stress?

Chronic stress can have negative effects on your health, but that doesn’t mean all stress is bad. In fact, your body perceives some healthy behaviors as stressful, even though they ultimately have a positive impact on metabolic health, insulin sensitivity, and glucose levels. Here are some examples of activities that are good for you, but may trigger a temporary spike in glucose levels due to stress.

Exercise/HIIT

Exercise — particularly HIIT (high-intensity interval training), maximum-effort weight training, and sprinting — can temporarily increase your cortisol levels and cause a spike in glucose levels. This happens because your liver releases extra glucose into the bloodstream to give your muscles enough energy to complete the workout [24]. While your body perceives it as a stressful event, don’t worry — it won’t contribute to long-term insulin resistance, and exercise has actually been shown to improve insulin sensitivity and glycemic control.

Sauna

When your body is exposed to the high temperatures of a sauna, your body releases stress hormones that trigger the release of stored glycogen for immediate energy, which is similar to the body’s response during intense exercise. This can cause a temporary, healthy glucose spike.

Intermittent fasting

Time-restricted eating (TRE) or intermittent fasting may be associated with increased levels of cortisol, depending on the number of hours you spend in a fasted state [25]. One study found that cortisol levels start to rise after 12 hours of fasting, though these levels come back down once you begin to eat [26]. Despite this, the science behind TRE suggests that it can actually help improve insulin sensitivity, aid in weight loss, and decrease postprandial (post-meal) insulin levels, though women may be more susceptible to hormonal shifts as a result of TRE-induced cortisol.

What are the best ways to manage stress levels?

Managing stress is key to regulating its effects on your metabolic health, and the best part is that stress management techniques are typically easy to do wherever you are. At Veri, we believe that metabolic health is intricately tied to the Four Pillars — nutrition, exercise, sleep, and stress. These pillars affect one another, meaning that maintaining good metabolic habits in nutrition, exercise, and sleep can help you manage stress. Here are some key ways to lower your cortisol levels and keep your blood sugar balanced.

1. Diet

As mentioned, heightened cortisol levels can make you reach for high-calorie foods, which are typically processed and/or full of refined sugar and fat — triggering glucose spikes and making it harder for your body to handle stress [27]. Maintaining a metabolically healthy diet is key to keeping cortisol and glucose levels regulated, and some research suggests that eating omega-3s and vegetables can help reduce cortisol levels [28].

2. Exercise

Getting regular exercise (approximately 150 minutes per week of moderate-intensity workouts) is key to heart health and improving insulin sensitivity [29]. But it can also reduce your cortisol levels, adrenaline levels, and increase the release of endorphins — your body’s natural mood elevators [30]. Even just 10 minutes of walking can reduce blood pressure and blood glucose [31]. For weekly exercise plans based on level of intensity, explore our article on the Best Exercises for Insulin Resistance.

3. Sleep

Just one night of bad sleep can make your body less effective at utilizing glucose and worsen insulin sensitivity. Not getting enough sleep on a regular basis can increase cortisol levels — which can result in more frequent sleep disturbances [32, 33]. Sticking to a consistent sleep schedule and making sure you’re getting enough sleep are key to managing cortisol and glucose levels. Try these 15 tips to improve your sleep hygiene.

4. Breathwork

Studies have shown that breathing through your nose to the count of four, then out through your mouth to the count of four, can slow your heart rate, reduce cortisol levels, and balance your glucose levels [34, 35].

5. Community

Finding social support in the form of a check-in with a family member or friend can do wonders for your mental health — it can help you build resilience to stress and help you maintain lower glucose levels [36]. One study found that socially avoidant individuals have higher baseline glucose levels and consume more glucose-rich foods than non-socially avoidant individuals [37].

For more strategies on managing stress, learn more at: How to Manage Your Stress for Better Metabolic Health.

Key takeaways

The feeling of stress is triggered by the hormone cortisol. In our evolutionary history, cortisol has played a key role in keeping us alive amidst environmental threats.
Acute cortisol is a short-term, normal response to stressful situations, and contributes to temporary insulin resistance. Chronic stress, on the other hand, feels inescapable and can lead to dysregulated glucose levels, insulin resistance, higher risk of chronic disease, and more.
Stress affects metabolic health physiologically (by promoting insulin resistance and hyperglycemia) as well as behaviorally (increasing your appetite for unhealthy foods and decreasing your motivation to maintain a healthy lifestyle).
Not all stress is bad: exercise/HIIT, sauna, and time-restricted eating may raise cortisol levels and glucose levels temporarily, but all improve insulin sensitivity and balanced glucose in the long run.
To manage stress, focus on maintaining healthy habits in your diet, exercise routine, and sleep schedule, as well as practicing breathwork and tapping into your community for on-demand relief and support.

References:

Written by: James Han

Reviewed by: Emily Johnson, MSc RD

Table of Contents

What is stress?
What causes stress?
How does stress affect insulin resistance and metabolic health?
Is there such a thing as “good” stress?
What are the best ways to manage stress levels?
Key takeaways

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