Stress: What it does to your body + brain health

Stress: What it does to your body + brain health

The way your body reacts to stress is a natural event designed to ensure your survival in the face of danger. Driven by your brain's perception of a stressor or danger, this automatic response causes the release of stress hormones, so your body is physically prepared and primed for instant action. The release of these hormones is what’s known as the ‘fight or flight’ response, to put you on physical high alert. Once the danger is averted and you begin to feel calmer, your stress hormone levels will start to return to normal.

There are a number of hormones that get released and they all play a role, but the 2 most commonly known hormones are cortisol and adrenaline. They work to keep your body primed and ready to act quickly.

They cause a chain reaction that activates several important organs, including your heart, increasing your heart rate, constricting blood vessels to raise your blood pressure, and directing oxygen-carrying blood to your muscles and lungs increasing your strength making it easier for you to run if you need to. Your brain also gets prioritised with more blood and oxygen supplied to enhance alertness and focus. At the same time, a few bodily processes get put on hold, like digestion and elimination, so blood and energy can be diverted to other areas, which explains why some people lose their appetite when they feel stressed.


What are cortisol and adrenaline good for in the body?

Many believe a certain amount of stress is a good thing because it helps them to function and remain “on their game”. This is the case in the short term, but in the long-term stress can have a wide-ranging damaging effect on your health which we’ll look at in a minute. First, let’s look at how cortisol and adrenaline help you when you’re stressed.


  • Helps to reduce inflammation, increase pain tolerance, and boost your immune system in short-term stress
  • Regulates blood sugar metabolism making sugars available to be used as energy
  • Increases fat and protein metabolism for energy production
  • Helps to regulate your sleep/wake cycle – typically peaking first thing in the morning it helps to get you up, keep you awake, and function even when you’re tired
  • Helps you with alertness, focus, and clarity under pressure


  • Dilates your pupils to maximise vision
  • Helps to increase your respiratory rate to increase oxygen levels
  • Helps to increase heart rate and blood flow like cortisol
  • Helps you with increased alertness, focus, and clarity like cortisol

Why it’s important to manage stress?

The obvious answer is that long-term stress is uncomfortable and who wants to feel like that all the time? The less obvious answer is high levels of stress hormones long term doesn’t just stress your mind and mood but also stresses and weakens important functions in your body. If allowed to persist this will have a long-term negative effect on your health and wellbeing. As we age we become less capable of buffering the effects of ongoing stress and new health issues start to show up. It could be unshakable weight gain, a skin complaint like eczema, or a digestive problem you've never had before. You might develop a sleep problem when you've never had problems before, or your always sharp memory recall becomes not-so-sharp. Here's how stress can impact different areas of your life.



High levels of cortisol before bed or during the night will keep you from sleeping well. You might have difficulty getting to sleep, have interrupted sleep, wake earlier than you need to in the morning, or a combination of all 3.

Sex hormones

Long-term stress can decrease libido, reduce fertility, cause sexual dysfunction for men, and irregular menstruation for women.

Weight and blood sugar levels

Weight gain is a common side effect of persistently high levels of stress hormones which is usually visible around the chest and waistline. A dangerous area to be carrying excess weight because this is where all your important organs, including your heart, reside. Excess weight in this area burdens these organs and inhibits their ability to function for you as well as they could. Stress also makes us prone to eating sugary, high fat foods for instant energy, derailing efforts to stick to eat well and maintain a healthy weight.


Muscles and heart

Constant stress forces your heart to work harder and faster putting it under unnecessary pressure. Stress also quickly depletes many valuable nutrients. Magnesium is a common mineral that becomes quickly deficient because it’s used in more than 300 enzyme reactions in the body, including your stress response enzyme reaction. Lack of magnesium causes muscle fatigue, tension and cramping, restless legs, and sometimes heart palpitations. Your heart is a muscle too which means it also needs good levels of magnesium to function.

Blood pressure

Long-term stress means long term your blood pressure could be higher than it needs to be. This can put pressure on your heart and arteries and can lead to more serious heart health issues down the track.


Ongoing chronic stress doesn’t just tire you out, it tires your immune system as well. Continued stress activates your immune system and keeps it switched on, and just like you, it will run out of steam and become slow to respond and less effective if it doesn’t get time to take a break and recharge. Stressed people often complain of getting sick the minute they’re on holiday, their first chance to relax and their immune system also takes a break, making them quickly susceptible to illness. People that have been stressed for a long time will also be highly prone to recurring bouts of illness on a regular basis.

Adrenal fatigue

Your adrenals are responsible for the production of cortisol and adrenaline, (as well as a number of other hormones). Just like you and your immune system, they get tired if they have to perform for extended periods leading to adrenal fatigue. This is when stress has been a factor for a lengthy period of time, and your can no longer keep up with demand. Adrenal fatigue leads to a complex of interrelated health issues, with extreme unresolved tiredness a predominant symptom.

Brain, mood & nervous system

Long-term stress causes the brain to become wired and overworked and is usually one of the first areas we notice affected when memory recall, focus, and accuracy become slow. Your emotional coping skills can also be weakened leading to mood swings, irritability, tearfulness, anxiety, and nervousness.


Stress also affects digestion whether it’s short or long-term. Some people get diarrhoea, while others just can’t seem to let go and poop every day due to tension. Stress also impacts your ability to digest and extract all the nutrients from food. You might also experience nausea, stomach pains, indigestion, heartburn, gas, bloating, vomiting, reflux, or lack of appetite.

Some tips and ideas for managing stress

  • Minimise/avoid the stress as much as you can
  • Breathwork exercises – even if it’s only 10 minutes per day
  • Meditation – guided or self-directed each day calms anxiousness and improves sleep quality
  • Take breaks – step away to reset
  • Get all the sleep you need
  • Eat a balanced healthy diet
  • Avoid skipping meals, alcohol, tobacco, and other substances
  • Regular exercise - move every day
  • Take a walk and detach from any devices
  • Listen to podcasts that inspire
  • Book a massage
  • Talk therapy – talk to someone you trust who's an awesome listener
  • Use good quality supplements to support you

Some supplements that can help to support your body's response to stress and support mental focus + stress include:

Lifestream Quick Calm 

Lifestream Brain Fuel Nootropics 

Magnesium Sleep Switch