Looking at animal pulse rates - it seems the slower the heart beats, the longer the animal lives. (elephant hearts are the slower than say a bird’s … ). Is this always true ?
Also, is it true that a larger animal (not an overweight animal) will have a slower heart than a smaller animal (of a different species) ?
Also, does a larger body weight imply a larger heart - when 2 animals are compared from different species ??
And lastly - In Humans - Do people with slower hearts (no other coronary problems - but low pulse rate) live longer than faster hearts (noother coronary problems - but faster pulse rate) ?
I looked in the archives - but could’nt find any answers. So any help is appreciated.
I think that the general rule is that among warm-blooded animals smaller animals require faster heart rates. My biology teacher told me that it was because smaller animals have higher surface area-to-volume ratios (true) and that this leads to faster heat loss (true) and that this leads to higher heart rates (I don’t know if this part is true, but it makes sense). If this were the case, then larger people should have slower heart rates than smaller people (accounting for things like general health). It’s also true that larger animals tend to live longer, but this is not as direct a correlation. So I imagine that there is some association between slow heart rate and life expectancy, but it’s far from a strict rule.
For the first question, Smithsonian had an article addressing this (I should look it up, but oh, well) Heart rate is a function of metabolism, and while in general metabolism co-relates to life expectancy, there are some notable exceptions.
The article was about a researcher in gerontology who theorized that biological life expectancy evolves to be about the same as life expectancy from external events. Or, a species isn’t going to have any evolutionary advantage to live to 200 years if all of them are killed off by predation or accident by the time they are 100. Thus elephants, giant tortoises and certain shellfish tend to live very long lives because they are not easily killed by predation or accident, whereas a gnat hasn’t a chance.
Wow. I was just thinking about this today. Must be a new meme.
Anyhow, I Googled around, and decided that while what Zyada said sounds and is probably true, that the correlation between just heart rate and life span is probably weak. I say probably because I have precisely 4 examples. I’ll give them in the order I googled 'em.
Started with:
Mouse
lifespan=3 years (2 year average expectancy)
heart rate=632 beats per minute
Cat
lifespan=15 years
heart rate=135 beats per minute
(so far so good, I think, cat lives 5 times longer and has a heart rate about 1/5 as fast)
Human
lifespan=90 (s/b higher, expectancy lower, easier to add though)
heart rate=72 bpm
(not as good there, heart rate dropped by half, lifespan quadrupled)
Elephant
lifespan=80 (expectacy=about 70)
heart rate=24 bpm (!)
(well, there goes that theory, thinks I)
Amazon Parrot
lifespan=80 (!)
heart rate= 200
(Another nail in the coffin. Although actually when I went back to check that, it turns out that figure is from the embryo of a parrot egg. Maybe an adult parrot has a lower one? I couldn’t find out, but I suspect it is pretty high).
Good goddess a normal human heart rate is 72? My resting heart rate is normally around 110-112. My blood pressure however, is extremely low. I do have an very fast metabolism, I weigh 102-105 and eat anything I want.
Would this mean I’m going to live fast and die young?
There’s a lot of variation in the human heart rate. The average is 72. That doesn’t mean it’s normal. In fact, I think that is not physiologically best. An athlete can have a HR of 40 or even less. Reason is that an athlete’s heart pumps a lot of blood with each beat; hence, it doesn’t have to beat as often, except when he’s “doing his thing.” But at rest, he can supply his body with enough blood at a very low (according to the average) HR. If your HR is 110, your heart is not pumping much blood with each beat; hence, it has to beat more often. However, your BP is low, so it’s probably not occluded arteries. It could be just “normal” for you, but also could indicate a low ejection fraction. Normal EF is 75% (75% of the blood in the left ventricle is pumped out with each beat.) If you haven’t had a cardiovascular exam recently, it may be a good idea to get that done. At least see your primary physician, if you haven’t done so lately, and see what he says.