what stress does to your body

What stress does to your body, mind and spirit

One of the biggest parts of the work I do my fitness clients is identifying situations in their lifestyle that cause them to become stressed. We all have triggers and once we have identified them we can deal with them.

Although I won’t go into fat loss strategies in this article, I will borrow some of the guiding principles for fat loss to help you understand what stress does to your body and how it can affect your ability to think clearly and stay positive as you go through life.

I often come across people who are on fitness journey and swear that they are “doing everything right” but aren’t seeing the results they won’t. Yes, they might be eating all the right foods for them and be consistent with their workouts but what they fail to take into account is how stress can throw a huge spanner in their works.

This is why.

The fight or flight response

Paintings from prehistorical times
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Humans have evolved with the ability to deal effectively with acute stress. Think about hunter-gatherers societies from pre-historical times: people would walk around all day looking for food and would sprint into intense action to either catch a prey or to avoid becoming one. Not to mention fighting off intruders threatening the survival of the progeny.

Even to this day our physiology is still connected to the reality of our ancestors. Although the stressors we have to deal with in modern society are different (think deadlines at work, unruly students, even worse parents, traffic jams, and so on), the way in which our metabolism responds to these situations hasn’t changed much over the millennia. And this is why stress is such a problem for us.

When we find ourselves in a stressful situation what happens is that our brain sends out messages the hypothalamus, pituitary gland and adrenal glands to deal with the perceived threat. In a fraction of a second the adrenal glands flood the body with stress hormones like adrenaline, noradrenaline and cortisol. These help us release extra energy to deal with the immediate threat, whether this involves fighting to the death or running away as fast as you can.

If you want to see a visual representation of the flight or flight response skip to 13 minutes and 15 seconds of this video https://youtu.be/5HZXiUouqII (unless of course you also love Krav Maga, in which case watch the whole lot to understand the scientific base of some of the techniques). It’s enlightening.

In modern days we hardly ever have to deal with physical threats like a pack of wolves jumping out from behind the wheelie bins, instead when we get stressed over an impending deadline at work we just sit there working away at our desk while the body is flooded with stress hormones ready for intense action. Every organ contributes towards preparing us for survival and as a result stress would cause us to burn extra sugar, fat and muscle if we either fight or run away.

When we don’t do that and stressful events are both recurrent and prolonged stress causes us to burn muscle over fat for energy. It also prevents us from releasing testosterone and human growth hormone into the bloodstream, both needed for growth and repair of damaged tissues after the stressful event. They also send a message back to the adrenal glands that the danger has gone and they can now stop releasing stress hormones and switch to a recovery state instead. If we don’t engage in intense activities in response to stress (or relaxing ones) the adrenal glands don’t get the message and stress becomes chronic.

Behavioural changes in response to stress

Although you should never look at any hormone in isolation as they always work in teams, for the purpose of explaining how stress can have an impact on your behaviour we will look at cortisol as this is one of your major stress hormones. Its actions are beyond your awareness, however the biggest impact that too much cortisol in the bloodstream for too long has is in the way it affects hunger and cravings.

This effect can also be linked back to how our ancestors used to deal with danger. Too much cortisol will cause you to feel less hunger in the short term but at the same time increase cravings for high energy foods at a later time. Think of it in terms of your ancestors leaving the relative safety of their caves to go and fetch food: if on their hunting trip they risked coming across lions it would make sense to go on a hunt fewer times (to reduce the risk of becoming food) and refuel less often with higher energy food.

This life preserving mechanism, when stress becomes chronic, has unwanted consequences for our brain chemistry leading to depression, anxiety, lack of motivation and a strong desire for highly palatable food. Hello emotional eating!

If you are a woman reading this things get slightly worse because chronic stress also affects the release of reproduction hormones which are your friends if you want to procreate and/or stay lean and trim.

The subtle signs that you are stressed and what you can do about them

You might think of anger and frustration as the only signs of stress but these are only the result of emotional stress. Unfortunately stress is also the result of injuries, too much food, not enough food, illnesses, physical exhaustion, too much exercise, not enough exercise, sleep deprivation, and so on.

You could measure your stress levels by having regular blood tests or you could take the lay-person approach and tune into your body to notice the subtle and not so subtle signs that you are experiencing stress eve when you think you aren’t.


Because of the changes to your brain chemistry brought on by chronic stress you might find that your sleeping patterns are disrupted. If you experience anxiety and depression you might well find yourself suffering from monkey brain… you know when you are ruminating on thoughts about situations and interactions replaying them in your mind over and over again. This is where you get caught up in a vicious circle: stress is causing you to stay awake and staying awake is stressing your body further. The hours that we spend asleep are the time when our body repairs itself, resets the stress hormones and gets rid of the toxins accumulated as a result of physiological process. It’s imperative that we aim at getting enough good quality sleep every day.

If this is a struggle for you try establishing a pre-bedtime routine consisting of relaxing activities like a hot bath, reading a book, doing some yin yoga or meditating for a few minutes.

Hunger & Cravings

As we have already discussed changes in your hunger and cravings are a sign that your body is stressed. Whenever your hunger diminishes but then you get crazy cravings for chips, crisps, pizza, burgers, biscuits, cakes and so on you should see this as a red flag and take corrective action. The best thing to do is to take some time out of your day and go for a long walk at a leisurely pace to give your stress hormones a chance to settle down.

Intense exercise can also be good, however if you are at the point where you can barely control your cravings it’s probably best to just walk as exercise can add stress to an already unbalanced metabolism. You could also have some dark chocolate as this has a positive effect on your brain chemistry reducing cravings for high energy foods.


When your metabolism is balanced and not under stress your energy levels will be fairly stable throughout the day and they will enable you to get on with whatever tasks are on your agenda. If you have peaks and troughs of energy then you know that your body is under stress. Pay attention to your diet and make sure your meals are balanced and contain all the macronutrients: protein, fats, carbohydrates (starchy and non starchy) and fibre. Be careful of fad diets that reduce one or more macronutrients dramatically unless of course losing fat in the short term is more important than your long term health and wellbeing.

Mood and motivation

If you wake up in a strop every morning and you can’t be bothered to get out of bed it’s another sure sign that you are stressed. Your brain chemistry has been affected and you need to take corrective action or your life will suffer as a result. Think about your significant other, your children, your friends, your co-workers and your students. They will all be affected by you not being at the top of your game.

Again, the food you eat will have a major impact on your brain chemistry and when you hit the magic combination of nutrients that work for you and your metabolism you will find it hard not to be in a better mood. However doing this will initially require a lot of willpower.

A good strategy to get around this issue is to spend time socialising with friends who are naturally happy and positive, let their enthusiasm be contagious and allow yourself to be uplifted by them. Engage in conversations that will generate laughter and take you away from your gloomy thoughts. It’s almost as good as going on holiday, in fact sometimes time spent with good friends is more healing than a holiday. I guess the keyword here is distraction.


If you are experiencing any of the above you can start keeping a diary and making notes of any signs of stress and what you do to counter them. Personally, when I feel the adrenaline rising I try to sneak in an intense workout or a jolly good sparring session but if that’s not possible I will focus on walking or even breathing techniques if I am driving and I cannot move.

You know what’s good for you and I encourage you to borrow some of the ideas from above and do something that will help you keep the stress under control. Your body will thank you for it.


I know I said I wouldn’t go into fat loss strategies at the beginning of this article, however if weight loss is on your mind keeping stress under control will be the key to your success. Even more so than working out and eating “all the right things”.


what stress does to your body
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About the Author Cristina

Personal Trainer. Thai Yoga Massage Therapist. Mental Health Ambassador. Martial Artist. Animal Flow Instructor. Social Scientist. Blogger. Sometimes Vlogger. Maid to the quadrupedals in my life.

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