stuart noble wrote:

Terry Fields wrote:
I need to monitor my blood pressure on a
daily basis, and to determine lomg-term trends I use the regressions
available in Excel to find the regression-line that results in the
least value of the variance - at least that has some authority to it.
A smoothing-filter exercise wouldn't even tell me the rate at which my
BP is changing.

Interesting. Care to post the formulae for that?
I've been logging my readings over the last couple of months, and all I
can deduce is that they're good in the mornings and not so good in the
evenings. The rest is truly random it seems.

Use statistics to get a grip on the figures; there lots of functions
available in Excel., although they might take a bit of finding.

I use a number of X-Y charts:

Get your data into columns (I didn't know this function was available
at the time, but put time and date into one column - 'format','cells'.
time and date, 'special', and pick a style you like) with Systolic and
Diastolic in separate columns alongside, then select all three
columns.

Insert Chart X-Y scatter Type: Scatter and follow the
instructions. The chart takes a lot of setting up once it's generated,
too long for me go go into here, but it's worth the exercise.

You can add a trendline of several sorts: linear regression,
polynomial, etc. and you can change these at any time. Get the chart
to show the regression equation and variance. Change between them to
fins the least variance = best fit of data. There is a fair range of
statistical functions in Excel

I've done this for a number of items: BP versus date I changed
medication, BP as a function of time of day, pulse rate ditto,
Systolic vs diastolic etc etc; its easy once you've tabulated the data
and mastered how to set up a chart.

My BP has a smooth 'hump' as a function of time of day, peaking at
about mid-day, about ten points above the early-morning and
late-evening readings, but due to the scatter it would not otherwise
be obvious. Mean readings are 138 sd 9 systolic, 87 sd 7 diastolic.

My BP is falling at about 1mmHg every 8 days, again not obvious but
calculated form the regression equation slope of about - .12,

Have a go if you're interested, it's well worth going up the learning
curve, even if it takes a little time. Currently I'm bamboozling my
doctor with the graphs and statistics, as I don't want to take yet
another pill....the last one didn't do me any good at all, and he
wanted to put me on a combination that is currently not advised as it
is implicated in the formation of diabetes. I said 'no'....