Ad lib / Weight / Caloric Intake / Blood Pressure / Pulse Pressure

[Guest guest]

Hi folks:

Regarding blood pressure issues in a paper referenced in the post

attached below, the following may be of interest.

Before starting CR my BP had started rising about three points a year

and was running 125/80. I assume that, had I done nothing, it would

likely now be ~135/85.

I started CRON at a BMI of 24·5 and targeted 21·0, not because I

thought BMI was such a wonderful criterion, but because it seemed

like a good idea at the time. I had seen the WUSTL CR BP data

averaging 100/60 realizing it was probably unrealistic to expect my

numbers to approach those, since mine had already started rising, as

commonly occurs with age. So, expecting other benefits, I slowly

reduced calories and reached my target in two years.

[A note about measuring weight: mine regularly fluctuates with

changes in intestinal contents and hydration in a range of five or

six pounds, sometimes more. Until recently, to judge what my 'real'

weight was, I plotted an imaginary line through the middle of all my

daily weight observations, and took that line to represent my real

weight. But that method is subject to rose-tinted interpretation!

So now I use CRON-o-Meter to calculate a moving average of my daily

weights. A 30-day moving average works well for me, not only for

weight but also for other erratic biomarkers, including blood

pressure.]

Surprisingly, I found that as my BMI declined, my BP followed. When

my non-rose-tinted, aberration-free, 30-day moving average, BMI

reached 21·1 my 30-day BP was 96/58. My systolic BP was ~40 points

lower than I guessed it would have been without CRON - 96 instead of

135. I was startled. Still am. This CRON stuff works better than I

ever imagined. And a 21 BMI can hardly be considered extreme - it

isn't far from the middle of the 'frequently-recommended-conventional-

wisdom-ideal' BMI, between 18·5 and 25·0.

But that is not the full story. Having reached my target I decided

to determine my ad-lib caloric intake and ad-lib body weight. I have

always had to restrain a large appetite to prevent my weight get away

from me to the upside. But I now realized I could find my ad-lib

weight by entering my ad-lib caloric intake into the Mifflin/St. Jeor

Equation. So I decided to spend a month watching what happened to my

weight and caloric intake while eating healthy foods without my usual

effort to restrict - but certainly NOT try to stuff myself full. I

took bananas and whole grain pita bread with me when on the move, and

ate my regular healthy foods at home, unrestricted.

WOW!!! Revealing results! After nine days I had to stop the

experiment! I found that on no day did I want to consume less than

3000 calories, and on no day did I feel a need to eat more than

3500. But, with a 'stable-weight' intake of ~1800 calories, this

meant a daily excess of ~1500! The effect on my weight was

predictable. The 1500 extra daily calories raised my real weight by

~four pounds, which was more than supported by the evidence offered

by my bathroom scale. Given time, my 30-day moving average weight

eventually rose exactly five pounds from where it had started.

So here is a punchline: over the same period, my 30-day average

systolic blood pressure rose by exactly ten points!! It is now clear

that for me each ONE pound fluctuation in my weight is associated

with a TWO point change in systolic blood pressure. Mifflin/St. Jeor

showed that this ad lib intake would eventually result in an

equilibrium body weight of over 350 pounds! And God only knows what

that would do to my blood pressure.

But a second key issue, raised in the referenced paper, is pulse

pressure - systolic minus diastolic. The paper reported that the

risk of 'a cardiovascular event' was negligible when pulse pressure

was below 40 - even for those aged 65 to 94. But pulse pressure is

also erratic and, therefore, difficult to assess reliably. That is

where, again, CRON-o-Meter's 30-day average comes in so handy. I can

quickly see that, at a 30-day average BMI of 21·1 my 30-day pulse

pressure was 38. But five pounds later, at a BMI of 21·9, my 30-day

pulse pressure had risen to 44. So, second punch line: my pulse

pressure fluctuated about 7.5 points per unit change in BMI. If

pulse pressure is as significant as reported, then this is useful

information, implying that rather than targeting BMI, which we know

is inadequate, it may possibly be better to target pulse pressure.

This, of course, is just one experiment in a single, eccentric (!),

mouse. But in practical terms it may mean that if an individual

reaches his/her 30-day pulse pressure target at a BMI of 25, then

maybe he does not need shave his caloric intake further. If it turns

out that a BMI of 19 or 20 is required to achieve the pulse pressure

target then perhaps that ought to be the objective? Also, it may be

that further restriction will not provide sizeable further benefit

once pulse pressure has been reduced below 40. Pulse pressure is

never going to drop to zero, so diminishing returns do set in

somewhere. Possibly modest additional restriction could drop my

pulse pressure to 35. Extrapolation suggests that might happen at a

BMI of ~20·7. This is just a few pounds lower, so is likely worth

the effort to find out.

It would be interesting to see any data others have which can be

compared with those above, since my experience may not be typical.

And it would be really neat if the wonderful people at CRON-o-Meter

could modify their software to calculate pulse pressure automatically

and then add it to the listed biomarkers. It would also be helpful

to me if they changed their default moving average setting from seven

days to 30, or organized it so that the user can lock in his

preferred moving average period, rather than having to set it each

time for each variable whenever he wants to see it!

Hope this may help.

Rodney.

--- In , " Rodney " <perspect1111@...>

wrote:

>

> Hi folks:

>

> Here is an interesting paper relating CVD event risk to blood

> pressure, using the data from the Framingham study:

>

> http://hyper.ahajournals.org/cgi/content/full/42/4/453

>

> Particularly notable, perhaps, is that among males aged 65 to 94,

> with pulse pressure less than 40 mm Hg the number of events is a

> microscopic 2 per 1000 (per year?)

[Guest guest]

Rodney,

This article is a bit dated (1997), but seemed relevant to your

observations. It doesn't discuss pulse pressure but does address SBP

and DBP vs BMI. Here is the abstract, although the entire article is

at the URL below. They found that BMI and SBP were linearly related

for men. Apparently for women, however, there is a threshold of

BMI=21, above which SBP is linearly related to BMI.

Relationship Between Blood Pressure and Body Mass Index in Lean

Populations

Jay S. Kaufman; C. Asuzu; Mufunda; Terrence Forrester;

Rainford Wilks; Amy Luke; E. Long; ; S.

Associations between body mass index (BMI) and blood pressure (BP)

have been consistently observed, but remain poorly understood. One

unresolved question is whether there is a linear relationship across

the entire BMI range. We investigated this question among 11 235 adult

men and women from seven low-BMI populations in Africa and the

Caribbean. We used kernel smoothing and multivariate linear and spline

regression modeling to examine gender differences in the relationship

and to test for a threshold. Age-adjusted slopes of BP on BMI were

uniformly higher in men than women, with pooled slope ratios of 2.00

and 2.20 for systolic and diastolic BPs, respectively. Men displayed

no evidence of age modification or nonlinearity in the relationship,

and the age-adjusted slope of systolic BP on BMI was 0.90 (95%

confidence interval [CI], 0.76 to 1.04). Women demonstrated both age

modification and nonlinearity. For both younger (<45 years) and older

(45+ years) women, the optimal change point for a single threshold

model was found to be 21 kg/m.2 Slopes of systolic BP on BMI above

this threshold were positive and significant: 0.68 (95% CI, 0.54 to

0.81) and 0.53 (95% CI, 0.29 to 0.76) for younger and older women,

respectively. Slopes below the threshold were essentially zero for

both groups of women, and the difference between the slopes above and

below the threshold was significant for younger women (P=.019). In

summary, we observed a threshold at 21 kg/m2 in the relationship

between BMI and BP for women but not for men. This contributes to the

effort to identify the mechanisms that underlie this relationship and

how they differ by gender.

(Hypertension. 1997;30:1511-1516.)

http://hyper.ahajournals.org/cgi/content/full/30/6/1511

- Diane

> >

> > Hi folks:

> >

> > Here is an interesting paper relating CVD event risk to blood

> > pressure, using the data from the Framingham study:

> >

> > http://hyper.ahajournals.org/cgi/content/full/42/4/453

> >

> > Particularly notable, perhaps, is that among males aged 65 to 94,

> > with pulse pressure less than 40 mm Hg the number of events is a

> > microscopic 2 per 1000 (per year?)

>