This was one of those books that completely opened my eyes to new knowledge and concepts I had not considered. Thank you Dr Maas. This is a summary of my learning:
The average female heart is 80 g lighter than an average male heart.
Female coronary arteries are narrower.
A standard ECG is based on a slim adult man who has a different chest size than a woman. In addition breast size may also alter the ECG lead position. These factors increase the chance the ECG is reported as abnormal despite no underlying cardiac problems.
Pregnancy can be considered as a stress test for the cardio-vascular system. For example if high blood pressure in pregnancy, pre-eclampsia, multiple miscarriages or gestational diabetes occurs it may suggest increased risk of cardio-vascular disease in the future.
These female specific risk factors (in addition to stress and increased inflammatory sensitivity) are relevant until age 65yrs then traditional risk factors are relevant. It is not known how heavy to weight these risk factors.
Male testosterone protects the heart from arrhythmias secondary to drugs.
Men who have a female heart transplant (under sizing) have a higher mortality. Whereas mortality in female is not affected if a male heart transplant (over sizing) is used. This blew my mind.
As women transition through to post-menopause the micro-vessels in the heart muscle can sometimes get stiff rather than blocked which results in micro-vascular angina. In addition heart muscle cells deteriorate with age. Both of these factors lead to heart stiffening.
Left heart muscle mass decreases more in men compared to women. Therefore heart failure in women is generally due to a stiffened heart whereas in men it’s often due to the loss of heart muscle and reduced ejection fraction.
Type 1 heart attacks are generally caused by a blockage in the coronary artery and are more common in men and women with very high cholesterol, heavy smoking & strong family history.
Type 2 heart attacks occur when the blood flow to the heart is insufficient to meet the demand at the time and are more common in women less than 65. I was unaware type 2 heart attacks existed however my local tertiary referral hospital (Leeds Teaching Hospitals NHS Trust) has a leaflet on this condition. How many other health professionals are unaware?
Atherosclerosis is different in men and women. 75% of men are suitable for percutaneous coronary intervention (PCI) or stent compared to 25% of women.
Around the menopause women frequently experience an increase in pulse rate, increasing shortness of breath on exertion and decreased exercise tolerance.
Coronary Computed Tomography Angiography (CCTA) is helpful in women with cardio-vascular risk factors and symptoms.
Improving lifestyle and treating risk factors including stress is extremely important in women.
Women’s blood vessels are narrower so the same blood pressure causes more damage than in a wider male blood vessel. Frequently in the book Dr Maas reminds the reader that good blood pressure control is very important, especially in women.
There is a seasonal variation to blood pressure: higher in colder weather and lower in warmer weather due to blood vessels narrowing (vasoconstriction) in colder weather and widening (vasodilation) in the warmer weather.
To avoid damage to the heart during radiotherapy to the left breast the patient is asked to take a low breath so the diaphragm moves the heart downwards out of the path of the radiotherapy beam. This made me smile - changing how a woman breathes during radiotherapy reduces heart complications in the future. How we breathe matters : )
This book has stimulated my curiosity and I would love Dr Maas' thoughts and comments on the following:
Carbon dioxide is known to dilate (open) blood vessels and release the bind between haemoglobin and oxygen leading to improved tissue oxygenation (Bohr effect). I have seen personally and clinically with my clients and patients the improvement in exercise tolerance when nasal breathing whilst awake, asleep and movement is re-established and carbon dioxide tolerance is improved. In my clinical experience the importance of 24/7 nasal breathing and good carbon dioxide tolerance is overlooked. Is this something you have tried with your patients? Feedback from individuals on my programmes who have improved their breathing efficiency:
'I walk to work up & down hills, I cycle up steep hills & I have started gig rowing recently & consciously use nasal breathing. I never feel out of breath unlike the others who are panting & groaning'
‘I am 68 years old and now recognise I've been a life long mouth breather. I can now skip continuously for 8 minutes whilst nasal breathing. Two months ago I would have needed to stop frequently due to air hunger'
'One benefit I hadn't particularly expected was how much it has benefited my Fit20 high intensity training! Even after a 4 week break, during which I had expected to go backwards, I actually went longer on the machines before muscle failure, managed to nasal breathe, and generally trained much better. My trainings were smoother, easier and my scores were much better
I am increasingly of the personal opinion that women become more carbon dioxide intolerant as they transition from peri-menopause to post menopause although I appreciate my view could be skewed by seeing women who are not feeling well. If this was true I wonder if promoting and encouraging women to breathe functionally (in and out of the nose, good carbon dioxide tolerance, breathing slow and with the diaphragm) could help maintain good oxygen supply to the micro-vessels of the heart and possibly reduce the risk of micro-vascular angina?
The linked editorial to a small study stated ‘Of particular interest was the improvement in endothelial function with high‐resistance inspiratory training in oestrogen‐deficient postmenopausal women, a group that generally does not demonstrate improvements in endothelial function with exercise training’ (1) The most basic inspiratory muscle training is maintaining nasal breathing whilst exercising. Clearly we need more research in this area however I have seen how this is possible when an individual commits to nasal breathing and improves carbon dioxide tolerance.
If you are interested in heart health I thoroughly recommend reading Dr Angela Maas' book 'A Woman's Heart' whether you are a health professional or not.
(1) Joyner MJ, Baker SE. Take a Deep, Resisted, Breath. J Am Heart Assoc. 2021 Jul 6;10(13):e022203. doi: 10.1161/JAHA.121.022203. Epub 2021 Jun 29. PMID: 34184555; PMCID: PMC8403307.
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