Hormones and you Part 3


Stress has the single most important effect over everything else regarding health, particularly hormonal and heart health but is the one area that we as women tend to neglect. If your sleep is poor, you are forgetful and easily irritated, then you’re probably just stressed. Sometimes the stress response is healthy – such as when playing sport or giving a presentation, but when it’s continuous, it actually begins to change your brain. If you don’t address it, it will definitely have a detrimental effect on your mental and physical wellbeing.

Chronic stress such as being overworked or having frequent arguments at home can affect brain size, it’s structure and how it functions, right down to the level of your genes.

[Here comes the science part – it’s easy reading so keep going!]


Stress begins with something called the Hypothalamus Pituitary Adrenal Axis  (HPA Axis)– it is a series of interactions between endocrine (hormone) glands in the brain and the adrenal glands, which are two triangular shaped glands that sit one on top of each kidney.

When your body detects stress, your HPA axis is immediately activated and releases a hormone called cortisol, which primes your body for instant action (fight or flight).

High levels of cortisol over long periods of time wreak havoc on your brain and can lead to burnout. For example, chronic stress increases the activity level and a number of neural connections in the amygdala – your brain’s fear centre.  As levels of cortisol rise, electrical signals in your hippocampus (the part of the brain associated with learning, laying down memories and stress control), deteriorates.

The hippocampus also inhibits the activity of the HPA Axis, so when it weakens, so does your ability to control your stress. A negative catch-22. L

Unfortunately, that’s not all. Cortisol can literally cause your brain to shrink in size. Too much of it results in loss of synaptic connections between neurons and the shrinkage of your prefrontal cortex.  This is the part of your brain that regulates behaviours like concentration, decision-making, judgment and social interaction. It also leads to fewer new brain cells being made in the Hippocampus. This means chronic stress might make it harder for you to learn and remember new things. And it also sets the stage for more serious mental health problems such as depression and eventually Alzheimer’s disease.


The effects of stress may filter right down to your brain’s DNA. An experiment showed the amount of nurturing a mother rat provides her newborn baby plays a part in determining how that baby responds to stress later in life.

The pups of nurturing mother rats turned out less sensitive to stress because their brains developed more cortisol receptors which stick to cortisol and dampen the stress response.

The pups of negligent mothers had the opposite outcome, so became more sensitive to stress throughout life. These are considered ‘epigenetic’ changes and so they affect which genes are expressed without directly changing the genetic code. These changes could be reversed if the mother rats were swapped.

There’s a further surprising result: the epigenetic changes caused by a single mother rat were passed down to many generations of rat after her. In other words, the results of these actions were inheritable. *

It’s not all bad news though!

There are many ways to reverse what cortisol does to your stressed brain. The most powerful weapons are exercise and meditation, which involve breathing deeply and being aware and focused on your surroundings.

Both of these activities decrease your stress and increase the size of your hippocampus, thereby improving your memory! 

A note of caution though: choose your exercise carefully as you get older. Many women get to their forties and decide to ‘get fit’ and run a half marathon. This is extremely stressful on your body, bad for your joints and really ageing. Do yoga, Pilates, dancing, walking or swimming instead.

I also recommend the ‘Headspace’ meditation app – they offer a 10 day free trial of short guided meditations and then there’s a small monthly fee or search for meditations on youtube - there are loads of free ones on offer.

Good nutrition, adequate sleep and keeping well hydrated will also work wonders to bring your stress levels down.