blood pressure questions (and max hr)

chrisw12

Nothing to do with training really but I know we get a very scientific brigade on here (sometimes)

max hr=220-age is the mean for the population, correct? Does anyone know if this distribution is normally distributed?

Most people say that the formula doesn't work for them, which you'd expect mathematically.

Now when I go to see the nurse to take my blood pressure, she'll often say '...mmm that's a bit high...'

What does she mean by this? Is blood pressure like max hr in that it us a unique metric for each individual. In which case my high reading might be high compared with the population but might actually be normal for me?

cedargreen

I think the max heart rate of 220 minus age is more a rule of thumb than a statistical average, and I don't think my max is anywhere near this but maybe I'm just not pedalling hard enough.

To some extent, blood pressure is the same- what is normal for you is not necessarily normal for someone else. However, there are fairly well accepted ' normal ranges' for blood pressure.

The nurse should have told you what your BP is. BP has two numbers- the top (larger) number is systolic pressure created by the pumping action of the heart, the bottom (smaller) number the pressure between heart beats.

'Normal' BP would be systolic in the region of 100-140, diastolic less than 100.
Systolic greater than 140 is considered raised, greater than 160 high, greater than 180 very high- these are not official ranges. So a 'normal' BP would be 126/ 78 for example.

Bear in mind that BP changes constantly in response to exercise, stress etc- hence 'white coat syndrome' where BP goes up when checked by a doctor due to anxiety.

I would ask the nurse what your BP actually is- just saying it's high isn't much use

vitesse169

My mhr is 186bpm, it should be by the rule of thumb 171, which shows what a load of twaddle that is. Again, blood pressure is a personal thing - there is a band of 'normal'...

johncp

max hr is indeed a personal thing and has no bearing on health - in contrast to blood pressure. Population studies suggest that a bp of 140/90 or less is associated with a lower incidence of heart disease in the population as a whole, so it's misleading to say that a bp may be "normal for you". It may well be, but that doesn't mean that you are not at higher risk of heart disease! So if nursey is muttering that its a bit high, ask what it is and what (if anything) you need to do about it

chrisw12

So John what you are saying is that there's a correlation between high blood pressure and 'risk of heart disease'?

and again this is different to max hr because there's no correlation between fitness and max hr.

Tom M

For the origins of the 220-age rule of thumb there's an interesting paper on it here:

http://faculty.css.edu/tboone2/asep/Robergs2.pdf

I would imagine that the difficulty in trying to establish any kind of normal distribution of max HR is in getting sufficiently large numbers of subjects, particularly older ones where there is issues in reaching a 'true' max (e.g. what exercise, motivation) and inherent health risks.

What other posters have said is good, and no, there is no correlation between fitness and max HR. HR declines with age due to changes within the area of the heart that initiates the electrical impulse, and less flexible arteries to some extent.

In terms of the association between BP and health risk, yes in the general population a higher BP is correlated with a higher risk of heart disease. However, if you have a raised BP, this does not necessarily put you as an individual at risk. You should perhaps find out your numbers as it's useful to know these things. Do bear in mind that a BP reading is just a snapshot of what is going on at that particular moment in time, and there are many different things that can cause BP to alter, including inputs from the brain. This can cause the 'white coat' hypertension where just knowing you're aout to have it taken can cause a rise (consciously or unconsciously). For any kind of proper and useful diagnosis you need readings taken regularly over a much longer time course.

There are guidlines used for upper limits, but they are only guidelines. People can fall outside that and still be perfectly fine.

jimmcdonnell

Right - to set the record straight about high blood pressure; I have 'essential hypertension' (fancy way of saying "you have high BP but there's no good reason for it, like 95% of sufferers").

'Normal' BP is considered 140 over 90, but that tends to change over time in response to research etc. 'Normal' was considered 130/80 for years when I was first diagnosed. The second figure, the diastolic, is as has been mentioned, the pressure in between beats, ie when your heart is 'at rest', so this is considered the more important number.

A BP of greater than 140/90 is considered a good indicator of increased chance of cardiovascular disease - not necessarily dropping dead of a heart attack, but things like stroke (makes sense, no? A stroke is a burst blood vessel in the brain, so if the pressure is high, burstage is more likely). In my opinion, I'm not worried too much about dropping down stone dead, but high BP increases the risk of me dropping down only partly dead.

When I was diagnosed, my BP was averaging 190/110 - mental!. I had weekly doctor appointments for 3 months to monitor it, to make sure it wasn't a random spike or white-coat syndrome. When it became apparent it wasn't, I was put on medication (for life) to manage it. Over a couple of years, the doc worked out a cocktail of meds which keeps it under control.

Posting here is all very well, but I'm guessing no doctors have volunteered an opinion - go and see yours if you have any worries. Given that the NHS is banging on a lot about preventative medicine, they should thank you for trying to help them avoid expensive medical treatment you'll no longer need in later life if you catch it early.

Of course, chances are your BP is fine, but it's got to be worth a few minutes of your time if you have any suspicion there's something not right...

Oddly, the fitter I've got and the more I've cycled (especially recently), the higher my BP has got, so we've just changed my meds to cope with that.

I've never smoked, I drink hardly at all, and there's no family history.

Slow1972

chrisw12 wrote:

So John what you are saying is that there's a correlation between high blood pressure and 'risk of heart disease'?

and again this is different to max hr because there's no correlation between fitness and max hr.

High blood pressure increases risk of a number of things including heart disease and stroke. If you have high blood pressure over a prolonged period it can also damage your kidney function (I have high bp if not medicated and the doc gets me to have a kidney function test every year).

Get it tested again and ask for the reading. If its still high you may be suffering from white coat syndrome - I think the docs can fit a monitor that takes your bp during the day.

Docs used to be more concerned over the bottom figure than the top one and a figure over 100 was a benchmark for concern. When I did a bit of reading into it there was research which suggested that if you're going to get your bp medicated, you may as well medicate down to the usual level (around 120/80) rather than keeping it just under the concern limit. This seems to make sense to me (after all if there is risk of heart disease /stroke etc, it doesnt just kick in over 100, it will increase incrementally in line with raised bp) and after a chat with my doc I had my dose increased a year or so for this reason taking my bp down from around 140/90 to 120/80.

If its still high they can do all manner of test to try and find a cause but if nones found its down to diet / exercise and/or medication. I've found that since I've got fitter from riding more, dropped a few stone and don't now drink that much alcohol that, combined with daily medication my bp's fine. You can pick up home monitors for about £10 to £20 if you want to keep an eye your bp yourself, that's what I tend to do.

But everyone's different, my missus' bp is usually around 100/60 without any medical interference.

nephrocycle

Essential hypertension is high blood pressure in absence of another identifiable cause. The vast majority of patients with hypertension are in this group. Systolic is the first reading and diastolic is the second reading. Systolic hypertension is just as important as diastolic. In practice both are usually elevated. The guidelines for treatment are continually changing as more epidemiological evidence becomes available. The risk for hypertension increases as we get older.
Treating hypertension reduces risk of heart disease and stroke. Generally the lower the better down to systolic of 120.
Diagnosis is based on serial readings though very high initial readings usually require treatment. 24 hour readings are sometimes used to investigate initially or guide changes to treatment.
Treatment is medication based though weight loss and salt restriction can result in significant BP reductions. Treatment is lifelong.
I would advise anyone with hypertension to have a full checkup including kidney function, Cholesterol and cardiac investigations - at least an ECG and probably echocardiogram +/- exercise treadmill or non invasive stress imaging of heart - prior to embarking on strenuous exercise. Moderate exercise is of course recommended and will also reduce risk of diabetes.
JS NHS Consultant