“Is it HRT you really need or an iron test instead“ I asked her during the weekend when she mentioned that she had started on HRT recently for her hot flushes, but she hadn’t noticed a difference. Her inquisitive look told me that she had no idea what I was talking about. But I was serious. You see, at 50 years old, she is a regular runner – she often told me that she runs around 10km a day, five times a week – whatever the weather.
It was her night sweats that troubled her the most, keeping her awake at night and feeling hot during the day, but still she did her daily runs – despite her exhaustion. However, she didn’t know what her iron levels were doing. That’s when I told her, if she wasn’t sleeping, it would be worth checking them.
It is well known in sport and exercise science that female runners are at higher risk of low iron levels. For women in menopause who exercise, it’s the same. But not sleeping, low iron and menopause changes, also impact on temperature and hot flushes. That’s why women in their menopause transition also run a higher risk of low iron levels.
Persistent tiredness, feelings of lethargy, upper respiratory tract infections and of course, not sleeping are well known symptoms of over-training syndrome, but so too are night sweats, hot flushes and a temperature regulation system, that is out of balance. But there’s more to the low-iron issue in menopausal women. And it’s to do with the circadian cycle of our liver and the role of iron in this process.
And you don’t have to be a runner either – whether you are sedentary or active, during your menopause transition, monitoring your iron levels is an important part of your hot flush management. So, if you are lining up for your HRT, then perhaps ask to get iron and ferritin (stored iron) levels checked.
Vitamins and minerals are essential to a myriad of physiologic functions, and a deficiency results in a wide variety of disorders. Among these disorders is the inability of mammals to maintain body temperature adequately in the cold or in the extreme heat. Whether you live in the hotter Northern Hemisphere or the cooler Southern Hemisphere at the moment, and whether you are on HRT or not, you need to understand that in menopause or post-menopause, there is an intricate link between your sleep, your hot flushes and your iron levels – too little or too much and your temperature regulation gets out of balance.
When I first began to have hot flushes and high blood pressure as I moved into my early 50s, nobody mentioned my lack of sleep, my iron levels, nor the fact that I was a regular exerciser. The aches and pains arrived as did the injuries from the running I was doing and slowly I normalised my constant feelings of fatigue, as I’m sure many of us do.
The increased body-heat I felt around 6pm when I was cooking dinner, supervising kids homework and multi-tasking a host of other home activities was energy-zapping. But these days I know better, and understand why those endless expensive supplements weren’t helping to reduce my body temperature.
Not sleeping was messing up my circadian rhythm. In turn, this was messing with my body’s temperature regulation and the exercise I was doing was messing with my iron levels, which I finally learnt, were low.
The overnight sweats and constant heat I felt, was due to my higher blood pressure, higher heart rate and low iron levels. The sweating was my body trying to cool down.
With new research emerging this year about the link between circadian rhythm, body temperature variations and our immune system function, I’m not surprised that the researchers have called this connection ‘a tangled threesome’. [Coiffard, Diallo et al, 2021].
Your circadian rhythm (the regulation of your body’s 24 hour clock) strongly influences your human biology and disease states. Almost all of the functions of the human body show circadian pattern that is under control of a biological clock. From our blood pressure to our immune health, to our temperature control, to liver health and gut function, our circadian clock matters and during menopause, our iron levels matter to our circadian clock and how our liver functions to regulate glucose overngiht. If we aren’t absorbing iron, it makes sense that our sleep is impaired and our hot flushes and night sweats worsen – especially in those of you who are exercising intensely.
Every major organ in your body works to your circadian night/day cycle and if you aren’t sleeping, then this can affect the uptake of nutrients that your body needs during mid-life and beyond. This includes iron.
If your iron is out of balance, then this not only affects your fatigue, but also your hot flushes and/or night sweats and your immune health. There is a cascade of changes that occur when your circadian rhyhm is out of balance including inflammatory changes to your blood vessels and organs. As such, your blood pressure, heart rate and hypothalamus which controls temperature regulation. All of these organs are affected when iron levels are low (or high) and when you aren’t sleeping. Blood pressure changes can then lead to higher heart rate and increased sweating as the body tries to reduce heat.
If your iron levels are low and you are doing a lot of exercise as you transition menopause, then your body goes into distress. It’s no wonder you are feeling hot and bothered – even in winter.
But researchers suggest that there is more to iron that previously thought – it is important in regulation of glucose uptake by the liver overnight. University of Utah researchers show that dietary iron plays an important role in the circadian clock of the liver. Judith Simcox, Ph.D., a University of Utah postdoctoral fellow in biochemistry, is the study’s lead author.
“Iron is like the dial that sets the timing of the clock,” Simcox says. “Discovering a factor, such as iron, that sets the circadian rhythm of the liver may also have broad implications for people who do shift work.”
We all know that sleeping all night is an important factor in our health. But so too are your iron levels. Both these things impact the regulation of your body temperature, It’s also why, if you are an exerciser, then you may need to back off the intensity a bit, until you sort out your sleep. Female athletes have to do this as well.
Therefore, not only do you need to sleep to beat the heat … but you also need to know what your iron levels are doing.
Some of what I suggest to the women on my 12 week programmes, includes implementing evening routines and foods which are evidenced to help to turn around their circadian rhythm, lower their blood pressure and hot flushes, especially after a busy, stressful day at work. When we feel stressed, then this can be a trigger for hot flushes and night sweats too.
Whether you live in a hot or colder environment, managing your temperature regulation during your menopause transition is important.
Physiological body temperature is approximately 37˚C in healthy humans with approximately, a 1˚ variation within the circadian cycle. If you want to manage your hot flushes in menopause and you want to reduce your blood pressure and improve your immune health, then you need to sort out your circadian cycle as well as your iron levels.
It’s why the very first module I have in the MyMT™ programmes is simply called ‘Sleep All Night’ – it’s that important to your hot flushes and blood pressure management. It’s why, some of you find that despite the Menopause HRT and endless supplements, your hot flushes remain with you right into your post-menopause years (and yes, I’ve written about the dangers of high-iron levels in post-menopause women and why this can also affect hot flushes).
There are numerous factors that disrupt your circadian rhythm during menopause, including:
- The type, timing and amount of food you eat. Women on my programmes know that high protein diets increase heat production in the body. Protein has the highest thermo-genic (heat generating) effect. Many daily protein calculations are derived from sports nutrition studies, so I change this calculation to reflect women’s health and ageing research. Furthermore, our body needs glucose from starch carbohydrates and metabolism of this is better in the morning. Numerous women get off all carbohydrates and go on high-fat Keto diets, but there are certain carbohydrates that we need for our cardiac health and circadian cycle.
- The level of inflammation in your body going into menopause (those of you doing lots of exercise, please take note!).
- How efficiently you can dissipate (remove) the heat from your skin as sweat. This emerges as a problem in women during menopause, as skin (our largest organ), changes in response to the decline in oestrogen. We don’t sweat as efficiently as we used to.
- Whether you are a shift-worker. Night workers display significant circadian rhythm abnormalities, including disruption of the body temperature. I have lots of shift workers on my programmes and I work with them to put in place strategies that help them prepare for sleeping in the day.
- Whether you work late into the night and go to bed late.
- Whether you are deficient in iron or high in iron (this can happen in post-menopause).
- The amount of physical exercise or activity you are doing, as well as how aerobically fit you are.
Whilst I have my foundation programmes for women to choose from depending if they are overweight or not, I also have a 12 week exercise programme, which many women opt to do after they have sorted out their symptoms. This programme is called Rebuild My Fitness, and in this programme I teach women that how quickly your heart rate returns to normal after exercise is now seen as an important marker, not only as a measurement of aerobic fitness, but also as a biomarker of the circadian management of blood pressure. [Okutucu et al., 2011]. If your iron levels are low, then we know from sport and exercise science, that this also has a negative effect on how quickly female athletes recover after exercise.
And for those of you who only do Yoga or Pilates classes, you might want to explore your aerobic fitness levels – when your cardiovascular system is stronger and you feel fitter, then this has a positive effect on sleep and hot flush management. Having lost a lot of her cardiovascular fitness during the UK’s long lockdown, Chris, a yoga instructor from London, was mainly doing yoga and pilates online. So, understanding that boosting her aerobic fitness was crucial to her symptom management, was an important step for her.
The regulation of your body temperature is synchronized by your body clock and this is regulated by light reaching your tiny pineal gland every morning. This is why our brain needs to register a contrast between day and night – to ensure that our body experiences a reproducible rhythm in behaviour, waking in the morning and sleeping in the evening.
This helps our brain to ‘rest’ and ‘wake’ which in turn helps to regulate the function of other circadian clocks on many peripheral tissues, such as the liver, heart, arteries, skin and lymphocytes.
For women going into menopause and beyond, this is crucial to know, because every one of these regions in the body are declining in oestrogen and as such, our menopause transition affects the function of other organs in our body. Hence, as women on my 12 week coaching programmes discover, if we sort out our circadian rhythm changes during menopause, and we see what our iron levels are doing, then we sort out many of our other symptoms, including hot flushes and night sweats.
I talk about this in my online Masterclass on Menopause and give you some solutions in this wonderful educational module for you as well – and yes, whilst it’s 2 hours long, because I’ve pre-recorded it, you can ‘pause’ me anytime you like.
Dr Wendy Sweet (PhD) Member: Australasian Society of Lifestyle Medicine/ My Menopause Transformation Founder.
Coiffard, B., Diallo, A. B., Mezouar, S., Leone, M., & Mege, J. L. (2021). A Tangled Threesome: Circadian Rhythm, Body Temperature Variations, and the Immune System. Biology, 10(1), 65. https://doi.org/10.3390/biology10010065
Jehan, S., Giardin, J-L, Auguste, E., et al (2017). Sleep, Melatonin and the Menopausal Transition: What are the links? Sleep Science, 10(1): 11-18.
Okutucu, S. & Karakulak, U. & Kabakci, G. (2011). Circadian blood pressure pattern and cardiac autonomic functions: Different aspects of same pathophysiology. The Anatolian Journal of Cardiology. 11. 168-73. 10.5152/akd.2011.031.
Reinke H. & Asher G. (2017). Circadian clock control of liver metabolic functions. Gastroenterology, 150: 574–580.
Rizzi, M. et al. (2016). Sleep Disorders in Fibromyalgia Syndrome. Journal of Pain Relief, 5:2, 1-5
Sharma, S. & Kavuru, M. (2010). Sleep and Metabolism: An Overview. Int. Journal of Endocrinology, Article ID 270832, 1-12.
Simcox J., Mitchell T., Gao Y., et al. (2015). Dietary iron controls circadian hepatic glucose metabolism through heme synthesis. Diabetes 64:1108–1119 pmid:25315005