Calculating Target Heart Zone While Using Beta Blockers

The usual calculation is 220 minus age X 50-85%.

Literature, including that from the Amer. Heart Assn. is very vague on
this subject when beta blockers enter the picture. It would seem to
me that your resting heart rate should be used in the calculation. In
fact, your resting heart rate is never used in calculating target
heart range, even people not using beta blockade.

Researched the Internet and the most detailed guidance I could find
said that people on beta blockers should undergo a treadmill exercise
test to determine target heart range.

1) Why is cardiac science so generic (220 minus age X 50-85%) for
people not on betas, yet so specific for those using betas?

2) And why is an individual's resting heart rate never considered?

Jack wrote:
> In fact, your resting heart rate is never used in calculating target
> heart range, even people not using beta blockade.
> [....]
> 1) Why is cardiac science so generic (220 minus age X 50-85%) for
> people not on betas, yet so specific for those using betas?
>
> 2) And why is an individual's resting heart rate never considered?

The simple answer to the latter question is: do a google search for
"Karvonen". You will find that the resting HR is not "never
considered".

(But caveat emptor: Karvonen was developed by statistical analysis of
data for highly-athletic individuals. The purpose of Karvonen is to
raise their performance. It might not be appropriate for people whose
heart rate is adversely affected by medication.)

The general answer to your questions is: there is an attempt to
simplify -- to the extent of oversimplification. In fact, many
age-based formulas have been derived by statistical analysis and linear
regression. Some formulas incorporate gender. "220 - age" was merely
the first. Recent analysis suggests that it is not the best. But all
of the formulas are close in their results, and all are equally
inaccurate. "220 - age" is used so pervasively largely because of its
simplicity.

Finally, it is widely known that the only way to determine your true
MHR is to have a maximal stress test under clinical conditions, which
typically involves the use of a treadmill. That suggestion has never
been specific to or limited to people on beta blockers. What might be
specific to beta blocker users -- but probably also users of a lot of
other medications -- is that the age-based formulas are even more
inapplicable to them. I have not heard that myself; but I would not be
surprised if it were true.

(The age-based formulas are based on data derived from mostly-healthy
sample groups, although some samplings specifically target over-fat
individuals to one degree or another.)

In any case, the three main reasons why people do not take the trouble
to get a maximal stress test are: (1) cost; (2) inconvenience; and (3)
risk. It is usually sufficient to use a combination of HR monitoring
and "listening to your body" (aka "perceived exertion"). Generally,
only people with known heart health risks and serious athletes need to
bother with maximal stress tests.