The Physiology of Burnout and Why It Matters

Burnout is more than just feeling tired—it’s a state of overwhelming exhaustion that affects your mind, body, and emotions. While it’s easy to think burnout is just about being overworked, it’s actually a complex process that disrupts many systems in your body, and is a sign that your body has been pushed too far for too long. In my last article (Understanding Burnout) we looked at the symptoms of burnout and identified those at greatest risk of developing this condition.

Knowing a little of the science behind burnout can help you better understand what’s happening inside your body and why certain recovery strategies—like rest, proper nutrition, and stress management—are so important.

Let’s break down the key physiological changes that happen in your body during burnout and explain how they impact your overall health.

What Is Burnout?

Burnout happens when you’re exposed to stress for an extended period, without enough time to rest or recover. Stress itself is normal and can even be helpful in short bursts, like when you need to meet a deadline or tackle a tough problem. But when stress becomes constant, it starts to wear you down, causing changes in your body that make it harder to cope.

How Chronic Stress Affects the Body

When you experience stress, your body kicks into "fight or flight" mode to help you deal with the challenge. This process is driven by the hypothalamic-pituitary-adrenal (HPA) axis—a system that connects the brain and adrenal glands, which sit on top of your kidneys. Here’s how it works:

• The hypothalamus (in the brain) sends out a signal that there’s a stressful situation.

• This prompts the pituitary gland to release a hormone called ACTH (adrenocorticotropic hormone), which tells your adrenal glands to produce cortisol, your body’s main stress hormone.

• Cortisol helps by giving you a quick burst of energy, raising your heart rate, and sending extra blood to your muscles.

This response is helpful in short-term, intense situations. But when stress becomes long-lasting, your body stays stuck in this "fight or flight" mode. Over time, high levels of cortisol and constant activation of the stress response can cause a variety of problems.

The Role of Cortisol in Burnout

Cortisol is a normal part of the hormonal response to daily life and has a regular rhythm in our bodies that wakes us up in the morning and keep us active during the day. It’s only during prolonged stress that cortisol become a problem.

In the early stages of burnout, your body is flooded with cortisol, keeping you alert and ready to deal with challenges. But as time goes on, your body can’t maintain this high level of activation. Eventually the adrenal glands struggle to keep up, leading to fluctuating or even low cortisol levels. This leaves you feeling constantly fatigued, drained, and overwhelmed—hallmarks of burnout.

Long-Term Effects of High Cortisol Levels

Here’s how prolonged stress and elevated cortisol affect different parts of your body:

• Immune System: High cortisol levels suppress your immune function, making it harder for your body to fight off infections. You may get sick more often or take longer to recover.

• Heart and Blood Pressure: Chronic stress puts extra pressure on your cardiovascular system, increasing your risk of high blood pressure and other heart problems.

• Blood Sugar Levels: Cortisol raises blood sugar levels to provide quick energy. Over time, this can lead to insulin resistance, which increases your risk of developing type 2 diabetes.

•  Digestion: When your body is in "fight or flight" mode, non-essential functions like digestion slow down. This can lead to digestive problems like bloating, stomach pain, or constipation. Cortisol also disrupts the balance of bacteria in your gut, contributing to further digestive issues. Chronic stress can lead to problems like irritable bowel syndrome (IBS) or acid reflux.

• Sleep Disruption: High cortisol levels, especially in the evening, can make it harder to fall asleep or stay asleep, leading to a vicious cycle of exhaustion.

• Muscles and Joints: Chronic stress can lead to muscle tension, which causes aches, pains, and headaches. 

Effects on the Nervous System

Your body’s stress response also involves the autonomic nervous system (ANS), which controls automatic processes like your heart rate and breathing. The ANS has two main parts:

• The sympathetic nervous system (SNS), which revs up the body for action (fight or flight).

• The parasympathetic nervous system (PNS), which calms the body down (rest and digest).

In burnout, the SNS is constantly activated, while the PNS is suppressed. This imbalance leaves you feeling anxious, tense, and on edge, even when you’re trying to rest.

Hormonal Changes Beyond Cortisol

Burnout isn’t just about cortisol. It also affects other hormones that play key roles in regulating your mood, energy, and overall health:

• Adrenaline and Norepinephrine: These "fight or flight" hormones stay elevated during burnout, making you feel anxious and on high alert.

• Thyroid Hormones: Burnout can affect your thyroid function, leading to symptoms like fatigue, weight gain, and sensitivity to cold.

• Sex Hormones: In both men and women, stress can reduce the production of hormones like estrogen, progesterone, and testosterone. This can lead to issues such as low libido, irregular menstrual cycles in women and reduced sperm production or erectile dysfunction in men.

• Mood Hormones: Burnout impacts neurotransmitters like serotonin and dopamine, which are responsible for regulating mood. Low levels of these neurotransmitters are associated with depression, anxiety, and a lack of motivation.

Burnout isn’t just about feeling tired or overwhelmed—it causes real, physical changes in your body that can affect your health in multiple ways. By understanding the science behind burnout, you can begin to form a road map towards better health

Recovery is about making changes that allow your body to rebalance and heal by bringing cortisol back to its normal functional level. These include stress management, good nutrition, quality sleep and rest, sustainable and regular exercise, and supportive relationships. In the following articles, we’ll explore each of these in more depth.

The good news is that the body is resilient. With the right support and care, it can recover from burnout, allowing you to restore your energy, balance your hormones, and rebuild your sense of well-being.

Rebecca