Rod Kersh
Person-centred physician

Know your numbers. Individualism in a time of statistics.

Nahal Hermon (Banias), 2019. Photo by Rod Kersh
Nahal Hermon (Banias), 2019. Photo by Rod Kersh

Years ago, just after I had joined my surgery as a partner, I wrote a series of blogs for our Facebook page.

One related to the importance of knowing your numbers.

Specifically, blood pressure.

Since that time, the world has changed. Many own smartwatches, we have had Covid where at the very least heart rate and oxygen saturations became part of the lingua franca of those interested in their physical health or wellbeing.

And now, at the end of 2023, where are we?

Yesterday, I visited one of my patients at home. She lives with her husband in a small tidy mid-terrace house. My patient struggles with her breathing and mobility, she has postural hypotension. This latter, a condition related to changes in blood pressure when moving from lying or sitting to standing which can result in dizziness, falls or collapse.

Her husband has been assiduously recording her blood pressure, taken whilst lying then standing, which he emails me every couple of weeks.

As we talked, I looked across at their dining room table; an orderly arrangement of blood pressure cuff, oxygen saturation meter and notepad sat alongside boxes of medicines.

My patient knows her numbers.

I never asked whether her husband checks his own blood pressure.

My mum, in the last twenty years of her life suffered with epilepsy (her first memorable generalised seizure the night of my cousin’s wedding, a year before I entered medical school.)

For the next 15 or so years, until his own death, my dad religiously recorded every one of her seizures on the calendar, kept on a wall in their kitchen, usually with an ‘X’ to retain a degree of confidentiality I imagine, for any visitors or guests.

There is something fascinating about the way in which some older men, who for most of their lives have taken the role of ‘looked after’ by their wives, switch to become carers.

For some, like my patient’s husband, it is a natural transition, for others a struggle.

My dad found it hard at times.

Why this diversion into the past?

It is the documentation of life which I find interesting.

Sometimes I ask relatives or carers to reduce the frequency of the measurements – they (usually men) become BP-happy, checking once or twice daily recordings, day after day – this is excessive; a medicalisation of life.

Our blood pressure is interesting.

When raised it is a potential and silent killer, either slowly eroding your heart, kidneys, and brain with reduction in function or suddenly with stroke or heart attack.

Do you know your numbers?

When did you last check your own blood pressure?

I review my own periodically and it runs-true, in the region of 130/70 which is adequate. I don’t have a fantastic family history.

Last week (as a patient), I attended a clinic at one of our local hospitals.

It was part of a cardiac assessment to determine whether I have inherited a cardiac abnormality that affects my brother. A form of hypertrophic cardiomyopathy, it is the causative agent behind some otherwise healthy young people dying suddenly from cardiac arrest.

To save your angst, I can confirm that my heart is healthy, left ventricle and general function are spot on.

As I arrived early, having rushed a ward-round then Christmas present giving followed by some work-related calls I arrived at the department flustered.

This was where I had worked over 20 years before as a junior doctor.

Returning was overwhelming.

A doctor arriving somewhere as a patient is a stressor.

My blood pressure was up which the nurse thoughtfully accepted and repeated a little later after it had time to settle.

Blood pressure goes up and down through the day. We call this diurnal variation. It has to do with a rise in the morning, probably to give our ancestors extra oomph to hunt rabbits and drops through the day, appropriately in time for bed.

There is an entire science of blood pressure monitoring, where the number are analysed for peaks, troughs, and timings.

One of my favourite medical terminologies is ‘reverse non-dipper which is the situation of blood pressure rising instead of falling at bedtime, a particularly sinister sign.


I began this blog querying whether you know your numbers.

The idea came from listening to this morning’s podcast, What Matters Now with Amanda Borschel-Dan and Haviv Rettig Gur discussing the results of recent polls conducted in Israel, the West Bank, Gaza, and America.

The numbers demonstrated the percentage support for or against the war, the ideological or other opposition to a Hamas-led future for the Palestinians and other questions relating to Antisemitism, foreign aid, and the existence or not of War Crimes in the conflict.

It was all numbers. 64 per cent this, 21, that.

I have long been a number cynic.

Even, dare I say of blood pressure.

I had better explain before anyone reports me to the General Medical Council.

I used to, back in the day, reference the old Guinness advert which aired in the UK in the late 90’s. It quoted, 88.2% of statistics are made-up.

I used to relate this to medical students, usually inventing my own stat.

The idea wasn’t to make them dismissive of study results, more to provide them with a degree of scepticism when considering absolutes.

‘New drug, Xylophone101 cures 32 per cent of people,’ for example.

The caution being, what does it cure and what does ‘cure’ mean? What are the complications or side effects of the treatment? What about the other 68% who are not ‘cured’ – are they worse-off? And, the sine qua non of person-centred medicine, does it matter on an individual basis?

Statistics help inform, they do not offer certainty to the person you are treating.

This all shifts into concepts such as ‘numbers needed to treat’ and ‘numbers needed to harm’ which relate to the respective patients who must either unnecessarily or appropriately receive a tablet or medicine for them to benefit, as an example, to prevent one heart attack, 100 people might need to take a daily Aspirin for 10 years in certain situations (these are my zombie statistics, for illustration only).

If 30 of these people, taking Aspirin for 10 years develop stomach ulcers and 2 of them die as a consequence, the net risk might be considered dubious, if you (the doctor) take into account other individual patient variables such as a person’s history of ulcers, other medicines taken, whether they smoke, drink alcohol and so on, you enter a world of shady data which is within every clinical decision.

For the most this is interesting and keeps me busy.

On the Podcast Amanda and Haviv discussed the numbers, taking what I felt to be an open an honest approach to the results considering the perspective of the young Palestinian living in Jenin versus the old New York GOP supporter.

All of this is fascinating although it only adds flavour to our perceptions, like grains of salt, it can enhance or overwhelm.

Over the past two and a half months, 78 days, since October 7th, my head has been spinning with facts, figures, impressions, and thoughts.

This week on my way to my hospital appointment, I drove past a shop displaying a ‘Free Palestine’ sign with three or four flags in the window.

Last night someone sent me photos of Palestinian flags atop lampposts in Sheffield. These, raise my blood pressure. Sending me into an almondemotion, my primitive-lizard brain (amygdala) on alert for further threats.

I didn’t explain to the nurse that my elevated blood pressure likely was affected not only by my arrival at the clinic but also the waiting in traffic beside the Palestinian flags.

‘What should you care?’ You might ask, well, I do. It is hard at times to control your emotions, particularly in traffic.

I wonder, had I driven along and seen an Israeli flag, whether that would have had a similar or inverse effect on my blood pressure?

(Rod, your blood pressure is only 80/40, are you OK? ‘Yes, sure,’ I dreamily reply, ‘I just saw a vision of Zion.)

I haven’t seen any Stars of David recently.

My suspicion is that, were I to fly a flag in my garden it would attract unwanted attention, perhaps a rock. That however is conjecture and based upon my own fluctuating prejudices.

It appears from recent polls that within the West Bank, since 10/7, support for Hamas has increased significantly as has a belief in the necessity of armed struggle against Israel, this in contrast to the results of those living in Gaza.

I can only imagine the citizens in Ramallah perhaps in the past two months have spent more time on Tik Tok than their Gazan peers (1.3 billion Chinese people exposed to Antisemitic tropes, imagine the implications, recently suggested Jason Harris of the Jew Oughta Know Podcast).

Who knows?

I am biased by my own perceptions, influenced by my upbringing, race, heritage, nationality, and life experiences.

Another trope I use in my lectures, mostly in relating to those living with dementia is, ‘If you have met one person with dementia, you have met one person with dementia,’ this means, don’t take your one-off experience as a generalisation. Everyone is unique. There is no such thing as a ‘dementia patient’ only ‘Enid, 88, retired lecturer, living with dementia,’ just as there is only one Jibril, 41-year-old doctor, Jericho resident or Efrat, 34, structural engineer, living in Haifa.

We are so easily drawn-into collective accounting, it is one of the biggest flaws of being human.

Forget humans, think people, no, think person.

I am me; you are you; your thoughts, feelings, emotions, and ideas are particular to you and warrant appropriate consideration, not diminishment through a collective interpretation of the actions of ‘people’ – take me as I am and I will take you, that way we can talk, discuss, hope, collaborate, and imagine a future of co-existence.

About the Author
Dr Rod Kersh is a Consultant Physician working in Rotherham, South Yorkshire. He blogs at
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