HRV and menopause

by Janet Birkmyre

Looking back, I can remember a 50+ track cyclist telling me “It all changes and becomes so much more difficult after 50”.  I did not think too much on it at the time, I was in my early 40’s and still improving (I did not start competing until I was 36) so I could not begin to appreciate the wisdom she was sharing.

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Jan storming to a win in the sprint at BMCR Road Race Championships.

Photo credit to Stuart Day

Tracking HRV

Just when I thought I had a handle on my Heart Rate Variability (HRV) and the stressors which affect me personally, I found peri-menopause and now menopause have thrown a hand grenade into all of that thinking and it is time to start over again.

Using ithlete I can measure the variability in the timing of my heart beats and that gives me an insight to the parasympathetic (rest-and-digest) and sympathetic (fight-or-flight) elements of the autonomic nervous system.  A high HRV number tells me I am rested and ready to go, while a low reading suggests my system is stressed and warns me to proceed with caution. 

With ithlete Pro, I track my HRV daily to understand recovery and the impact of work, travel and sleep as well as what I eat and drink on my ability to handle training.  After more than a decade I now have a good understanding of what the numbers tell me and a proper respect for the red warnings which occasionally tell me I am over-stressed or perhaps getting ill.  ithlete also helps me understand when and how gently to get back into training after illness.  If I am in doubt I check in with my coach, Steve Cronshaw and we will make a decision together.

“It is a system which works, I have lost fewer days to illness than I did before I used ithlete”.

Something has changed

Recently I have become aware that something has slowly being changing.  So slowly in fact that it is difficult to fully understand and it is only now, looking back that I can see my HRV numbers have dropped steadily over the last couple of years.  Five years ago a reading in the mid-80’s was a sign that all was good, even if my legs felt sore from training, I could push on with confidence knowing that while I might be over-reaching, I was not in danger of over-training. These days I am happy for a reading in the mid-70’s and I can only put this down to menopause.

That much is – for the experts at ithlete anyway – simple enough but female hormones are unbelievably complex and subject to change at different life stages as Dr Stacey Sims explains below.

“Estrogen tends to increase vagal tone (ie the ability of your ventral vagal nerve to regulate your heartbeat), which is what devices measure to give you HRV.  Progesterone, though “calming” in the brain, has the opposite effect on the vagal nerve and overrides estrogen’s effect on increasing vagal tone… In perimenopausal women, the hormone ratios are completely different and in postmenopausal women, they are flatlined, so the hormonal influences on the vagal nerve are altered.  In both cases, you end up with more fight-or-flight activity and less rest-and-digest activity, especially after menopause.”

The bottom line is that most women will, like me, see their HRV numbers decrease as they transition from pre to peri and then onto menopause, and over time they will establish a new baseline.  Of course, the transition is entirely individual and even if it weren’t, there is currently very limited research into this area.  My experience tells me this is a time to get in touch with how I feel, commit to completing the subjective measures in ithlete Pro and to monitoring sleep quality too.

It is a difficult and confusing time for many women, with mental resilience challenged and so many physiological changes taking place.  There is however some comfort in knowing that what I am seeing is normal and I feel a follow-up blog coming up on the subject of HRT and HRV… it might just be a game changer for me!