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Cortisol (aka the stress hormone) and the 5 things you need to know

OK, so we all know that stress isn’t good – yet in our modern world avoiding stress seems close to impossible. What is happening on a biochemical level when we are stressed is really fascinating. In years gone by, long-term stress mostly revolved around food being scarce or in the form of floods, famines and wars. The stress was related to basic survival.

Today, our long-term stresses are more likely to be financial worries, relationship concerns and uncertainty, concerns about health and also body weight. Here we explain how cortisol works, as it can be your friend or one of your worst nightmares.

  1. Cortisol is essentially influenced by our behaviour and how we think.
    For some, the thoughts might flow like this: “Oh, my goodness, it’s Wednesday, I have an important meeting at work and a report to finish but there’s nothing at home to pack for the children’s lunches and little Ellie’s uniform is still in the wash and I forgot to ask Jenny to take Billy to soccer practice after school and I have people coming for dinner tonight and where is that good skirt I was planning to wear, and goodness I forgot to pay the electricity……. So it goes on. Many of us live like this every single day. When this happens continuously it can lead to a chronic pattern of stress response, therefore increased cortisol output, which in turn can lead to an alternation in your metabolism.
  2. Cortisol is catabolic.
    This means that it breaks proteins down into their building blocks, which we know as amino acids. Proteins make up our muscles and cortisol signals them to break down, as the body perceives that fuel is needed. Added amino acids are also needed in the blood to repair tissues (even though you may just be watching TV, with your financial or relationship concerns mulling around your head!). The amino acids released as a result of the signalling of cortisol can be converted back into glucose, which your body thinks may be useful to assist you in this time of stress. If you’re not active, this increase in blood glucose will not be used, and insulin will have to be released to return blood glucose levels to normal by returning the glucose in the blood to storage. As we know, glucose is stored as glycogen in the muscles and the liver. Over time, the evening level of the hormone starts to spike again rather than continuing to decrease. At this stage, you still make optimal levels in the morning and you’re able to bounce out of bed and get going with reasonable energy, but by evening levels are creeping up. This is one way that good sleeping patterns can be challenged.
  3. Elevated cortisol increases our risk for disease.
    When cortisol levels become high, there are other changes in body chemistry that start to be revealed. It has been suggested that high levels of cortisol are a common thread behind what has been described as metabolic syndrome. By that we mean elevated blood pressure, high cholesterol and insulin resistance, the latter condition being a key warning that if nothing changes soon, Type 2 diabetes is likely to occur.
  4. Cortisol can slow down our metabolism.
    We know that our bodies are wired for survival and that cortisol tells our cells that food is scarce. However, another of its roles is to slow down our metabolic rate. A slower metabolism means you burn body fat for energy slower than you have previously, as cortisol is designed to make sure that you survive this perceived period of famine.
  5. Cortisol can have a negative impact on your digestion.
    Cortisol activates the sympathetic nervous system (SNS), causing all of the physiological responses previously described. Therefore, the parasympathetic nervous system (PNS) must be suppressed, as the two systems don’t operate simultaneously. The PNS is stimulated when the length of the exhalation extends. Known also as the ‘rest, digest and repair’ arm of the nervous system, when the PNS is activated it allows the body to prioritise digestion and nourishment. On the contrary, imagine what goes on in a cortisol-flooded, stressed-out body when food is consumed: digestion and absorption are compromised, and more frequently indigestion can develop.

So what to do? 
Managing stress will involve different strategies for different people. Most commonly however, a reduction in caffeine consumption (caffeine drives adrenaline production, our short-term stress hormone), incorporating a breath-focused practice such as yoga, meditation, tai chi or Pilates, so we include diaphragmatic breathing activates to aid the calming PNS arm of the nervous system. Breathing in this way lowers stress hormones very efficiently. Cook a nourishing meal, writing a gratitude journal or simply going for a walk in nature can also be of incredible help. Taking the time to nurture your body and your mind is key to leading a life of balance and wellbeing.

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