What effect does stress have on the body?



Stress is not necessarily a bad thing. Stressing the body is what many of us will do when we exercise, but we do that to get a positive outcome. You need to put your heart, lungs and muscles under stress to facilitate an improvement in strength and cardiovascular fitness. We also need stress to remind us to be prepared and ready for an interview or exam for example. Too much stress, though, can be very harmful to the body. According to the American Psychological Association, chronic stress is linked to the six leading causes of death: heart disease, cancer, lung ailments, accidents, cirrhosis of the liver and suicide. It is one of the biggest causes of preventable death in the UK.

So how do we learn to manage stress and what is the impact it has on our minds and bodies?

Central Nervous System

The central nervous system is comprised of the brain and the spinal cord, and can be considered the command and control centre of the human body. The central nervous system (CNS) communicates with the rest of the body via neurons linked to what is called the peripheral nervous system (PNS). When a stimulus is introduced to the body, receptors communicate with sensory neurons, which in turn communicate with motor neurons to affect a response within the CNS. Some of these responses could be called reflex responses, for example when your hand brushes close to a heated flame. The urge to pull your hand away from the heat is automatic, and happens outside of your conscious control.

Like any part of the body, the CNS can breakdown. A nervous breakdown can happen when the CNS is subjected to repeated and prolonged stress. It can also be caused by a chemical imbalance in the brain, usually linked to serotonin but also connected to nor-adrenaline, dopamine, acetylcholine and GABA (gamma aminobutyric acid). Worry, chronic stress, fear, anxiety, nervousness and panic attacks are all symptoms of a mental breakdown, also called a burnout. You could say that burnout relates to the burned-out nerves or synapses in the brain.

Allostatic load

Allostasis is the process of achieving stability (homeostasis) through physiological or behavioural change. The female menstrual cycle is a good example; the body regulates itself by undergoing a period of change each month. An example of homeostasis is our core body temperature; our bodies maintain the same temperature by releasing or creating heat (sweating or shivering).

The term allostatic load was coined by Dr. Bruce McEwen, a professor of neuroscience at Rockefeller University. Put simply, allostatic load is the wear and tear on the body that develops over time when an individual is exposed to chronic and fluctuating stress levels (Interestingly, not all types of stress evoke the same response; it’s the type of stress and how you deal with it that matters).

Every system in the body is affected by allostatic overload. Initially, the production of adrenaline and cortisol sharpen up the memory, keeping the individual focused in a time of danger. As the stress is repeated however, the neurons atrophy and memory becomes impaired. The immune system is impacted also; low levels of stress promote immune function by sending immune cells to the areas of the body where they are needed to defend against a pathogen. Chronic stress however, has the reverse effect of suppressing immune function, and the individual’s risk of chronic disease suddenly becomes elevated.

Stress and exercise

If chronic stress is left unchecked it can lead to physical and mental breakdown, illness, the disintegration of families and relationships, the loss of jobs and livelihood, and in some cases loss of life. At best, it makes life difficult, more challenging and less enjoyable. Now exercise can’t directly help certain things, like how to handle a difficult scenario at work, how to pay the mortgage, how to get your child into a good school or how to get a promotion, but it can help to improve your state of mind, help you sleep better and therefore think more clearly; it can help you think and communicate rationally and perhaps feel more relaxed and in control of other areas of your life. Exercise has been proven to decrease the production of stress-related hormones like cortisol, and increase the production of other hormones such as serotonin, adrenaline and dopamine, which together can contribute to making you feel more positive, happier and uplifted. There’s also something very rewarding about making a plan of action, and then getting ready and going out and doing it, whether it’s going for a run, completing an exercise session or just going for a walk. Just making a plan and sticking to it can be really gratifying. It can also help to take your mind off some of the negative emotions you might be experiencing, or give you some time out of the home or office.

Anxiety, depression and exercise

Exercise is often under-prescribed by the medical community as part of a treatment plan for anxiety and depression, but despite that is widely considered to be central to helping people manage their condition. It isn’t only the chemical responses in the region of the brain, (or specifically in the pituitary gland, which is not part of the brain but a small protrusion at the bottom of the hypothalamus), that help make people feel better about themselves, but also the physical changes can help improve one’s self-esteem and feelings of self-worth and competency.

The brain and exercise

There are numerous positive changes to the brain that occur during and after exercise (specifically aerobic exercise). These changes occur in different parts of the brain, and in some cases the benefits are still enjoyed even after you stop exercising. These benefits include:

  • Increased blood flow to the brain allowing it to thrive
  • Adaptations that mean the brain can turn certain genes on and off, which can have the effect of boosting brain function
  • Improved brain function can reduce the risk of diseases such as Alzheimer’s, Parkinson’s, strokes and cognitive decline
  • Generation of neurotransmitters such as endorphins, dopamine and glutamate as well as encouraging the production of serotonin
  • Supplies extra oxygen to a part of the brain called the hippocampus (responsible for learning and memory) and helps to create new brain cells. This process is called neurogenesis, and these new cells survive even after you stop exercising

One of the best ways to manage chronic stress is exercise, but it must be at the appropriate intensity, for the right time and the right type. If you are very stressed, it might be best for you to start with a gentle walk (see previous blog posts about disconnecting from tech and reconnecting with nature). If you’re worried about your stress levels, consult your GP as a first step.

Leanne Spencer is an entrepreneur, coach, TEDx Speaker, author of Remove the Guesswork, and founder of Bodyshot Performance Limited. Bodyshot is a health and fitness consultancy that helps busy professionals get more energy by removing the guesswork around their health, fitness and nutrition. Visit www.bodyshotperformance.com or email info@bodyshotperformance.com to register your interest in our services and connect with us on Facebook, Instagram and Twitter.

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