HAMILTON, Canada: Suffering a quarantine dip in mood? Struggling to find motivation to do anything? You are not alone.
Just six weeks of chronic stress can lead to depressive symptoms, even in people without a prior diagnosis. We are past that six-week point in this pandemic and you may be experiencing a depressed mood unlike anything you’ve experienced before.
Our research in the NeuroFit lab at McMaster University shows that exercise can prevent stress-induced depression. A brisk 30-minute walk three times a week is enough.
But even under the best circumstances, nearly half of young adults and 70 per cent of older adults find it difficult to be sufficiently active for good health.
THE STRESS RESPONSE
An unfortunate side effect of the COVID-19 pandemic is its impact on psychological distress and mental health. Psychological stress, such as a conflict with a family member, activates the stress response in the same way as a physical threat.
It all starts in the brain stem with the activation of the hypothalamus and its two parallel axes: The SAM axis (sympathetic adrenal medullary) and the HPA axis (hypothalamic pituitary adrenal).
The SAM axis works quickly. Through the sympathetic nervous system, it causes a rush of adrenaline into the blood, initiating the “fight or flight” response to unleash the body’s maximum power.
The HPA axis works more gradually. It induces a cascade of hormones that leads to the release of cortisol into the blood, which in turn liberates stored sugars from the liver and fat cells. This provides the body with the energy it needs to endure the stressors over a longer period of time.
In its acute form, stress is actually a good thing because it wakes up your brain and body for action and helps performance. However, in its chronic form, there is greater reactivity and slower recovery of the stress response.
That means the stress response is triggered more easily, in response to lower levels of stress, and takes longer to revert to a normal state. The result is major strain to the brain and body that can lead to symptoms of mental and physical illness.
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CHRONIC STRESS OF COVID-19
This pandemic is incredibly stressful. The abrupt halt to “life as usual” and the idea that things may never be the same has forced a rapid evolution in our collective self-identity.
As a result, many people feel like they’ve lost their place in this world. This adds extra tension to daily life, making us more reactive to seemingly minor events, and this can play a major role in forecasting our future brain health.
Under normal circumstances, people reported nearly a 50 per cent chance of having a stressful day. This number is likely higher while people are under stay-at-home orders.
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Although everyone feels worse on stressful days, people who have more extreme mood swings between stressful and non-stressful days are at an increased risk of developing depression and anxiety.
How long will this last? No one really knows.
Over time, this uncertainty and lack of control can alter our reaction to other stressors. Instead of “fight or flight,” we “freeze,” feeling helpless and lacking motivation. These are symptoms of stress-induced depression.
TONING THE STRESS SYSTEM
Exercise can help. Even though it’s technically a stressor and activates the stress response in the same way as a psychological stressor, the magnitude of the exercise stress response is acute and controllable by modifying intensity and duration.
Like strengthening a muscle, exercise “tones” the stress system so that it can tolerate a higher level of stress with less reaction and faster recovery. This makes us more resilient to all forms of stressors, even the psychological ones brought on by this pandemic.
Research from our lab and others shows that about 30 minutes of moderate-intensity aerobic exercise three times weekly can boost mood, reduce psychological distress and decrease symptoms of depression and anxiety relative to those who are sedentary.
When compared to antidepressant drugs, this dose of exercise is equally effective at treating stress-induced mental illness without the potential side effects of medication, such as nausea, fatigue or loss of appetite.
However, the sudden closure of gyms and recreational facilities, the restricted access to public parks and trails and the closure of daycares and schools may make it more difficult for people to be sufficiently active for good health.
Jenny J Heisz is Associate Professor in Kinesiology and Associate Director (Seniors) of the Physical Activity Centre of Excellence at McMaster University. Maryam Marashi is Master's Student, Kinesiology at the same university. This commentary first appeared on The Conversation.