Understanding stress is fundamental to understanding mental health. When you think of stress, you might picture being on edge, keyed up, and full of adrenaline. For many people, stress turns into feeling tired and burned out. Here’s why:
What is stress?
Stress is your body’s natural response to a threat. When you experience something your brain perceives as dangerous, it goes on high alert and creates changes within the body to prepare it to keep you safe. This is generally a helpful process that keeps you safe, but the brain’s assessment of immediate danger is not always accurate.
In modern times, many of our experiences of day-to-day stress are not immediate threats to our physical safety. Instead, we’re wondering if we’re going to get the promotion or if our friends like us, and the brain doesn’t have a great system to decipher the differences, so it goes on high alert anyway.
Fight, Flight, Freeze, or Fawn mode
That high alert process is often called fight or flight, although there are other responses like freeze and fawn. Our brains and bodies are evolutionarily primed to move into one of these response styles when facing danger, but that danger is not always the danger our brain thinks it is.
Fight
What your body is primed for:
Fighting off a wild animal to protect your family and food sources for the winter.
What it can look like today:
Confronting your family member when they repeatedly say harmful things.
Flight
What your body is primed for:
Noticing that the birds are flying away and running in the same direction to preemptively avoid a threat.
What it can look like today:
Not answering a text when you don’t know how to respond.
Freeze
What your body is primed for:
Identifying that a bear has spotted you, and attempting to stay as still as possible to not attract attention.
What it can look like today:
Becoming as still and silent as possible when your boss starts throwing blame around, so you don’t catch the brunt of it.
Fawn
What your body is primed for:
Placating the leader of the group so you don’t attract harmful attention.
What it can look like today:
Laughing enthusiastically at someone’s jokes despite them being harmful, so that you don’t become the one being made fun of.
Some people routinely go into one or two of these responses based on past experiences, but each can be effective for different situations.
Again, there is nothing inherently wrong with any of these responses, your brain is just attempting to help you get through a situation safely. But when our brain senses danger too often, or has trouble moving out of feeling like there is danger, it can take a toll and leave us feeling exhausted.

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Acute vs. Chronic Stress
Stress is sometimes acute, generally meaning short-term and needing immediate attention. People feel acute stress in response to things like car accidents, important job interviews, and social interactions.
But for many people, stress becomes a chronic experience, and can be focused on one overarching stressor, or on many smaller ones.
Chronic stress can also be a collective experience when there is something stressful in an environment that does not have a set resolution. Even if the threat is not right in front of you, the ever-present awareness that the threat could impact you can cause your brain to maintain a stress level that leads to tiredness.
For example, many people have experienced an increase in chronic stress over the course of the COVID-19 pandemic. We aren’t immediately fighting off a virus at all times, but the ongoing threat, increased safety measures, and constant calculations of risk vs. reward can take a toll when it comes to your brain’s stress responses.
Ensuring your safety during an ongoing threat like a pandemic can leave you feeling exhausted without a clear understanding of why.
How can stress affect you?
A moment of stress here and there likely won’t take a major toll on your well-being. But when you experience stress regularly, your mental and physical health can be affected.
Adrenaline crashes
Adrenaline is one of the hormones your body releases to help you successfully navigate a threat. In the moment, it helps you do things like run faster, see more precisely, and accomplish physical feats you might not otherwise be able to do.
After the immediate threat has subsided, your body will attempt to come back to baseline functioning, and when adrenaline subsides, it can feel like a crash.
This makes you tired because:
Adrenaline can feel like it “tricks” you into feeling energized and ready to tackle the world. When that feeling subsides, you’ll experience just how much energy it took for your brain and body to maintain that high level of arousal while you were stressed.
You may not have felt it at the time because the adrenaline was able to keep you awake and alert, but once it adrenaline wears off (and it often does quite quickly!), many people experience a sudden and intense feeling of fatigue. Sometimes that means an immediate desire to sleep, but it can also mean general grogginess or “brain fog”.
Think of this as a similar process to drinking highly caffeinated beverages. You likely drank the beverage in the first place because you were feeling tired or sluggish, and when the effects of the caffeine wear off, not only are you still as tired as you were before you drank it, you’re now tired from the activities you engaged in while feeling the effects of caffeine.
High Cortisol
Cortisol is another hormone released in response to perceived threats or danger. It serves many wonderful purposes like regulating blood pressure and blood sugar, helping with inflammation, regulating metabolism, and your sleep-wake cycle. But chronic activation of cortisol can negatively impact your health and wellness in many ways.
When your body is experiencing an acute threat, cortisol helps to shut down non-essential functions, so your brain and body can focus on your safety. In the short-term, this is something you can easily recover from, but if you are chronically stressed, these processes can be affected long-term.
This makes you tired because:
When you are stressed and experiencing high levels of cortisol, your sleep cycles can be affected, and you can generally not feel well leading to chronic feelings of fatigue.
Sleep Disruptions
On top of the hormonal and biological sleep disruptions stress can induce, sleep can be disrupted by racing thoughts, rehearsing “what if” scenarios, and prioritizing work or responsibilities over quality sleep.
Many people start experiencing scenarios in which they can’t quite remember whether they started sleeping poorly because they were stressed, or they are stressed because they are sleeping poorly. It can feel like a vicious cycle of compounding stress and exhaustion.
How does this make you tired?
Disruptions in sleep obviously lead to feeling tired, but they can also lead to compounding challenges in physical and mental health that in turn also increase feeling tired.
Many people experience insomnia that becomes worse over time; the more frequently they experience poor sleep, the more difficulty they have falling and staying asleep.
It’s not uncommon for people to experience getting used to a level of tiredness, even if they do not feel well as a result. When you are stressed and not sleeping well, your body can keep you awake and alert, but that doesn’t mean that you won’t feel completely exhausted while doing it.
What is Burnout?
When you are stressed for a long period of time, you might begin to experience burnout. Many people know about burnout in relation to jobs, but it can also be applied to family responsibilities, relationships, living situations, etc.
The American Psychological Association defines burnout as “physical, emotional, or mental exhaustion accompanied by decreased motivation, lowered performance, and negative attitudes toward oneself and others” and states that “it results from performing at a high level until stress and tension, especially from extreme and prolonged physical or mental exertion or an overburdening workload, take their toll.
How does this make you tired?
Once you reach a point of burnout, everything feels hard. Many people experience feelings of dread and complete exhaustion, and it can feel like there’s no end in sight.
When everything feels like it requires more mental energy to complete, it’s no surprise people feel tired when they’re burned out.
Tips for reducing tiredness when you are stressed:
Engage in exercise or movement
In addition to just being a great option for self-care and general wellness, movement is especially helpful when managing stress and exhaustion.
It may feel counterintuitive to go exert energy when you are feeling tired, but if stress is the cause of your exhaustion, exercise and movement can help your brain recalibrate to out of high alert.
If we take the example from above of a mountain lion charging at you, your brain and body are going to think that you are still in a dangerous situation if you haven’t moved (run, hide, or fight). Even if you were responding with freeze, that is an active process, not just continuing to go about your day.
Movement lets your brain and body relax knowing that it has “responded” to the threat, and while you may be tired from a walk or workout, that type of tiredness is one that helps you get quality sleep, and typically goes away after rest.
Engage in conscious rest
Conscious rest is more than just sleep or not completing work or responsibilities. Conscious rest is when you engage in an activity that is rejuvenating and makes you feel centered and relaxed afterward.
This could be a hobby like art or reading, watching a favorite show, calling a friend, or the more stereotypical choices like a warm bath or massage. The important piece is to signal to your brain and body that making time for these things is necessary and ok. Reducing your stress through these channels helps your body relax and step out of fight or flight mode.
If your stress stems from overscheduling or overwhelming responsibility and you don’t feel like you have the available energy to add in conscious rest, start small. Ensure you are taking the breaks you deserve (both in and out of the workplace) and look for moments you can carve out to prioritize even a few moments of conscious rest.
Amp up your sleep routine
Build up a bedtime routine that works for you, and over time this can train your brain to be prepared for sleep after you do it. Try putting away electronics and stimulating activities for a period of time before you go to sleep.
If you’re stressed, it can feel easy to get absorbed in a game, show, or book to check out of the stress for a bit, but make sure you prioritize getting good sleep by setting limits for yourself around those activities.
People respond to naps differently (for some it can disrupt nighttime sleep), but if you are feeling exceptionally tired during the day and have the availability to rest for a while, try taking a short nap (between 20 and 30 minutes is a good place to start).
Identify the source of your stress and take steps to overcome burnout
While these tips are helpful in managing stress, it’s important to know the source of your stress and take action to reduce it.
Of course, there are certain types of stress that are unavoidable. The challenges of parenting, grief, medical issues, or financial insecurity are stressful no matter how well you cope. But knowing what is causing your stress and tiredness is the first step to identifying what might be helpful in reducing it.
Reach out to your support system or take steps to create a new one. Find a therapist and start a path to healing. Make plans to remove yourself from toxic workplaces or living environments.
If you’ve already reached a level of stress that has led to burnout, this is especially important. Burnout cannot be fixed by more self-care or coping skills, there has to be a change in your experience, or the stress will continue. What that looks like will depend on the specific situation but make changes to prioritize your well-being.