Stress and sleep: How are they linked?

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Stress and sleep: How are they linked?

What is the relationship between stress and sleep, and how can we improve it?

The body’s stress response is an important, natural legacy of evolutionary biology.

Twenty thousand years ago, our hunter-gatherer ancestors experienced stress for the purpose of ‘fight’ or ‘flight,’ since environmental threats meant there was a genuine possibility of becoming prey. When the body was not experiencing stress, the default disposition focused on ‘resting and digesting.’

The stressors which we experience today are a far cry from those our ancestors tackled. Still, even low-level stressors can negatively impact our physical and mental health – and ultimately, our sleep – when experienced for an extended period of time.


stress and sleep
What is stress?

Essentially, stress is a physical, mental, and emotional response to changes in environmental or internal factors. For the most part, stress is experienced in small doses and simply allows us to act quickly and effectively should the ‘fight or flight’ scenario become prevalent.

However, when experienced over an extended period, it translates into an overwhelming feeling of pressure or a sense of being unable to cope. In today’s fast-paced society, constant demands and expectations can mean we are continually on edge. Mostly, as a result of feeling like being at everyone’s beck and call.

When stress is sustained for long periods, it is defined as ‘chronic’ or ‘long-term’ stress.

What causes stress?

When the body feels stressed, the adrenal gland (located on top of each kidney) releases a chemical that is often termed the ‘stress hormone’: cortisol.

Cortisol, when found in the body in appropriate levels, is responsible for naturally replenishing energy stores, and regulating blood pressure and sugar. So, we typically experience normal levels of cortisol when we wake up, or when we exercise.

On the other hand, when our body perceives a stressor, cortisol levels spike to kickstart this ‘fight or flight’ response. This hormone triggers glucose uptake and inhibits insulin production so that a supply of energy is readily available for our muscles. Alongside this, epinephrine increases our heart rate and forces blood through our bodies faster, so that we can tackle the immediate ‘threat.’

stress and sleep
Why does stress affect sleep?

When experiencing stress over more extended periods, cortisol is over-active in the bloodstream. Our blood pressure rises, the heart begins to race, and our minds are alert and focused.

When sustained, this effectively creates a constant disposition of feeling highly-strung. Our bodies are prepped to pounce or run, even though our ‘threat’ may not appear immediately obvious.

As a result, when high cortisone levels are maintained, we’re not allowing our bodies to rest and recover the way they should. And this can lead to a poor relationship between stress and sleep.

Recognizing stressors

Though modern-day humans are rarely at risk of becoming prey, we do experience regular, low-level stressors day-to-day.

Instead of ‘resting and digesting,’ our bodies are recurrently experiencing stressors and stimulations such as work demands, family commitments, and constant connectivity to mobile devices and social media.

Not everyone will respond to stressors in the same way. However, some indicators of stress can include emotional, behavioral, and physical changes, such as:

  • Fatigue and irritability
  • Anxiousness and/or restlessness
  • Poor decision-making
  • Weight gain/loss due to changes in appetite
  • Feeling disillusioned/depressed
  • Inability to concentrate
  • Insomnia

By recognizing these stressors, you can ultimately learn how to manage them – or avoid them altogether.

stress and sleep
How to improve the relationship between stress and sleep

If you are regularly feeling tired, irritable, or struggling to get to sleep at night, there’s a good chance that stress is negatively impacting your health.

While recognizing stress is the first step, managing it effectively will put you on the right path to better stress management, and more restful sleep.

Some effective means of managing stress can include:

  • Practicing relaxation techniques, such as meditation or yoga. Regulating your breathing and taking time to adjust helps you recover from stressful events.
  • Exercising regularly – just 5 minutes per day can reduce feelings of anxiety by reducing levels of cortisol in the bloodstream.
  • Managing your time effectively and sticking to a good routine. Better organization will reduce worry over tasks and deadlines, mitigating late-night overthinking.
    Mindful lifestyle changes such as those above will have a positive impact on your relationship with stress and sleep.

stress and sleep

Main takeaways

What is stress?

Stress is our brain and body’s natural response to negative stimuli, mainly caused by the hormone cortisol. It prepares our body for action by raising blood pressure, heart rate, and increases glucose uptake into our cells.

What causes stress?

Stress can be caused by a range of factors in our modern lives, from the daily commute to huge life choices. High-stress levels for an extended period can have myriad negative effects.

How does stress affect sleep?

When experiencing stress over more extended periods, cortisol is over-active in the bloodstream. When high cortisone levels are maintained, we’re not allowing our bodies to rest and recover the way they should – creating a poor relationship between stress and sleep.

What are some of the signs of stress?

There are several indicators of stress, starting with sleep: Insomnia, fatigue and irritability, anxiousness and/or restlessness, poor decision-making, weight gain/loss due to changes in appetite, feeling disillusioned/depressed, and inability to concentrate.

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