When activated, the fight or flight system leads to a series of physical changes in the body. Relevant to chronic fatigue, the fight or flight response causes things like muscle weakness, tension, fatigue, digestive symptoms, dizziness and headaches. This is because energy is directed away from usual bodily functions and towards organs and muscle groups that are essential for survival. Importantly, some of these symptoms can persist when the threat is gone and you no longer feel anxious.
Stress can also increase pain sensitivity, making chronic fatigue symptoms more intense. As discussed above, the fight or flight response is intended to be short lived. However, many of today’s stressful situations cannot be dealt with quickly. Chronic activation of the stress response often results in more severe chronic fatigue symptoms. In fact, research has suggested that the fight or flight system is overactive in people with chronic fatigue. In contrast, the system that reverses the stress response (called the “rest and digest” system), is said to be underactive in chronic fatigue.
When the fight or flight system is activated, the brain sends signals to the body to release stress hormones (i.e., ‘cortisol’ and ‘adrenaline’). In controlled amounts, these hormones prepare us for action. However, too much cortisol and adrenaline is bad for the body. For example, it can cause digestive, inflammation and immune system problems. These effects can lead to a range of problems, including chronic fatigue and other similar disorders. Researchers have shown higher cortisol activity in people with chronic fatigue compared to people without this condition.
The relationship between stress and chronic fatigue appears to go both ways. Having a chronic illness like chronic fatigue can be extremely stressful. Not only are there the direct symptoms to deal with, but there are often secondary problems that come from the illness. For example, many people report financial worries, relationship issues, and falling behind at school or work. The journey towards recovery from chronic fatigue can also be stressful, as people worry about their capacity to start new activities or resume old ones.
As you can see, stress and chronic fatigue interact with and worsen each other. This can create a vicious cycle that’s hard to break out of. Before moving on, have a think about the stress in your life. What aspects of life make you feel stressed? Are these short-term worries or ongoing problems? Does stress seem to impact your chronic fatigue symptoms, or vice versa?