MyMT™ Blog

The cause of your morning wake-up heat wave in menopause – the Cortisol Awakening Response [CAR].

“Do you know why, when I immediately wake-up, I get a heat surge through my body?” she asked.

The question immediately took me back in time. A few years ago, when in my early 50s, I experienced the same phenomenon. Even though I’m in post-menopause now, I still have the odd ‘heat surge on waking-up’ moment. When this happens, I now understand why, so I lie quietly take some deep, slow breaths to calm my respiratory rate and heart rate, before getting up to start my day. 

I first heard about cortisol and a phenomenon known as the Cortisol Awakening Response (CAR) when I was studying sport and exercise science and overtrained athletes. I never imagined that I would be going back to studying it during my menopause transition, many, many years later.

The cortisol awakening response is the acute increase of the cortisol level in the 30-45 minutes after awakening. CAR is believed to act as a “boosting” mechanism, to aid in physiologically preparing one for waking up and getting on with the tasks of our day and the morning heat surge you may be feeling, could be because you aren’t sleeping or your blood pressure and resting heart rate are elevated.

Because the cortisol-awakening-response is driven by your nerves and hormones (neuro-endocrine system), any irregularities depend on how balanced your hypothalamus, pituitary gland and adrenal glands are.

The connection that these three organs have is known as the Hypothalamus-Pituitary-Adrenal Axis (HPA axis) and the working of this axis is considered to be influenced by, and sensitive to, a host of psychological conditions and stressors. All of which affect your cortisol levels throughout the day.

Workplace and personal stress, over-exercising, insomnia, too much fasting and of course, the hormonal changes that we undergo in menopause, all affect your HPA-axis function, which in turn affects your cortisol response. Learn more here about the sign of menopause.

Cortisol is widely recognized as one of our stress hormones. This hormone has a diurnal (day-night) pattern and works in with our sleep hormone called melatonin. Cortisol levels are generally high in the morning and low at night, unless there are disruptions to its normal fluctuations throughout the day, such as when we are busy, exhausted or stressed.

The body makes cortisol in our adrenal glands, and in the context of athletes, cortisol works with other adrenal hormones and the liver, to help release the glucose stored in the liver for exercise performance. During exercise, these storage forms of glucose need to be continually released and turned over.

Hence, cortisol concentrations also increase during exercise. This powerful hormone also helps to free proteins from the muscle, to be used in the liver for the production and use of more glucose. This is why, for endurance athletes especially, they tend to not have the size of muscles that bodybuilders have. Increased exposure to cortisol increases muscle breakdown or catabolism. It’s the same for women doing lots of high-intensity exercise and not sleeping – the greater the exercise intensity, the higher the levels of cortisol.

As I’m always saying to women who come onto the MyMT™ programmes, ‘without proper recovery, intense exercise can lead to elevated levels of cortisol in the bloodstream and heightened symptoms of physical stress, even when exercise is not being performed. Such as first thing in the morning. For women in menopause, this elevated cortisol, can give them a hot flush on awakening.

For female athletes, the elevated cortisol can cause heart rate to be elevated in the morning too. There’s a reason numerous athletes wear heart rate devices – not only is this to monitor the intensity of their training, but it’s also to monitor morning heart rate.

Elevated heart rate and /or elevated cortisol go hand in hand – add on dehydration, inflammation, low blood glucose, and low iron levels, then in female athletes, elevated cortisol awakening response occurs.

But what if you aren’t an exerciser and you are waking up to hot flushes?

There’s another factor to consider when it comes to cortisol awakening response and hot flushes. Whilst research doesn’t support morning hot flushes being caused by Cortisol Awakening Response [CAR], what the research does indicate is that higher heart rate, anticipated stress and insomnia overnight can contribute to an elevated Cortisol Awakening Response, there is something else that is specific to women in menopause – and that is our changing and ageing blood vessels. I have talked about arterial or vascular stiffness in numerous blogs as well as in my Masterclass on Menopause, which is now online for you.

Because menopause is the gateway to our biological ageing, numerous changes are occurring around our body. This includes changes to our blood vessels and other organs. In an age whereby media and pharmaceutical companies focus on marketing botox and other external products to promote anti-ageing, the salient point of our internal cellular ageing gets forgotten.

When menopause arrives, there are numerous structural changes that occur in our body, not just changes to our oestrogen and progesterone levels. Because hormones travel in the blood, they contact virtually all body tissues, however, most of them have targeted actions specific to the different hormone receptors. Which is where our blood vessels come in and the relationship to elevated blood pressure, elevated heart rate and an elevated cortisol awakening response.

This is an important point for all women, not only those who are regular exercisers.  As we lose oestrogen, our blood vessels are ageing and this leads to vascular or arterial stiffness. The loss of elasticity in blood vessels and lymphatic vessels, means that we may feel more bloated, our legs may feel heavy, restless and aching (especially for exercisers) and our blood pressure and heat regulation may get out of balance too.

When we have busy, active lives, the vascular stiffness leaves us feeling exhausted. It can also leave us with an elevated morning heart rate – just like overtrained female athletes … or women not sleeping and feeling a bit burnt out with all that’s going on in their lives. This alone disrupts hormone regulation in the body and the reason for this is because the hypothalamic-pituitary-axis (HPA-axis) which regulates our stress response and the adaptation to stress in our lives, fails to do its job properly.

This is why feelings of overwhelm, high cortisol levels, insomnia and burnout, all mess up this lovely HPA-axis – especially during our menopause transition.

Some of you with overwhelming symptoms, may have had your hair, saliva or urine tested by Naturopaths for cortisol levels. Disruptions in HPA-axis functioning, due to chronic stress, are usually examined by investigating the level and course of cortisol during the day and the cortisol awakening response.

This CAR biomarker has shown to be independent of the general cortisol level in the body and thus provides relevant information on HPA-axis functioning (Schmidt-Reinwald et al., 1999).

Understanding why many of you may be feeling the heat on waking up is important. Not only because it helps you to put in place strategies to turn this around, but also to reassure yourself that it’s not just menopause, but related to the other changes going on around your body as part of ageing, such as inflammatory changes in your blood vessels. 

That’s why calming strategies are helpful, such as doing some slow breathing which helps to reduce your heart rate; cutting back on high intensity activity if you aren’t sleepine well, because this increases inflammation and working in with your circadian rhythm and the natural ebb and flow of your cortisol levels throughout the day and evening. In a normal cycle, cortisol should be high in the morning (but not too high) and over the course of the day, it should be lowering as you head towards evening. So, evening is the time of day to put your stress away and allow your body and brain to rest and recover. 

If you are struggling with your symptoms or menopause weight gain, then I hope you can join me on my 12 week progammes sometime. You can read about how they work HERE.

Dr Wendy Sweet, MyMT Founder/ Member: Australasian Society of Lifestyle Medicine.


Anderson, T., Wideman, L. Exercise and the Cortisol Awakening Response: A Systematic Review. Sports Med – Open 3, 37 (2017).

Langelaan, Saar & Schaufeli, Wilmar & Rhenen, Willem & Doornen, Lorenz. (2006). Do burned-out and work-engaged employees differ in the functioning of the hypothalamic-pituitary-adrenal axis?. Scandinavian journal of work, environment & health. 32. 339-48. 10.5271/sjweh.1029.

Nijm, J. & Jonasson, Lena. (2008). Inflammation and cortisol response in coronary artery disease. Annals of Medicine, 41. 224-33. 10.1080/07853890802508934.

Woods N., Mitchell E., & Smith-DiJulio K. (2009). Cortisol levels during the menopausal transition and early postmenopause: observations from the Seattle Midlife Women’s Health Study. Menopause, 16: 708-718

“If you have ever wondered if there was a clear easy plan to follow to sleep all night, reduce hot flushes and prevent or reduce your weight gain during menopause, then ‘welcome’ – you’re in the right place now.”

Discover how either of my two Menopause Transformation programmes might help you too or take my Symptoms Quiz below… 

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