• Question: I've heard that a babies heart beats faster, is this true? Why?

    Asked by markfalloon to Louise on 23 Jun 2010 in Categories: .
    • Photo: Louise Dash

      Louise Dash answered on 23 Jun 2010:

      I think this is true, but I’m hoping one of the others knows why!

      For unborn babies and newborns, the heartrate is usually about 120-140 beats per minute. I know this from experience having spent many hours hooked up to a monitor when I was pregnant! My second son was very premature and spent his first month in an incubator attached to lots of machines to monitor his heartrate and again it was mostly in the 120-140 bpm range. It’s much slower for an adult – at rest about 60-100 bpm.

Comments

  • Photo: Sharon

    Sharon commented on :

    Hi guys, yes, it is true, and it’s quite a simple reason really, Not really got anything to do with age, it’s to do with size. All babies and children have higher heart rates than adults. The reason is to maintain a constant temperature and good circulation. Small mammals have a larger surface area to lose heat from and therefore require a higher metabolic rate to maintain. In order for this to happen, a higher oxygen intake is required and a higher circulation rate, therefore higher heart rate.

    So, if you think of a baby, especially a premature one, like Louise’s was, they have a very tiny heart, which would have needed to work extra hard! Thats another reason very small babies are kept in incubators, to keep them nice and warm so their hearts don’t need to work as hard!

  • Photo: Jon

    Jon commented on :

    Wow – I didn’t know that about babies’ heart rates!

    My resting heart rate is around 45-48 beats per minute, in part because I do a lot of sport, and also because I don’t drink anything with caffeine in it (that raises your heart rate, and it takes about a day for your body to get rid of it, so if you drink tea, coffee or some soft drinks like Coke every day, you always have some in your system).

    Having a low heart rate helps with holding your breath for a long time underwater (I used to enjoy breath-hold diving, that involves trying to relax and slow your heart rate down when you dive under). When I was younger and training a lot more, I used to be able to slow it to just under 40 beats per minute. But the guy who won the Tour de France cycle race a couple of years ago had a resting heart rate of 30 beats per minute! Now that is awesome – but I’m too old to get mine down that low now, even if I trained loads 🙁

    One funny thing about having a low heart rate is that some heart monitors in hosiptals only record your heart rate if it is higher than 50 beats per minute. When I cracked a couple of ribs once and they hooked me up to a monitor to check I hadn’t punctured a lung (I hadn’t), the machine kept “flatlining” – saying I had no heart rate, and setting off an alarm!