when you are sat there doing not a lot your heart is still beating at a rate fast enough to produce enough energy to keep you going.
if you lift your arm to grab the remote ( do we still do that or do we shout at alexa now…) your heart responds by beating faster – your arm needs energy to move….
but your heart will have a maximum rate at which it can beat….
as you get older this maximum reduces slightly, most of us don’t need to worry about hitting the max for long with our lifestyles….
but if you are starting to get into getting yourself into shape, then keeping your heart rate bpm (beats per minute) at a high enough rate to work it – without overdoing it, can be important
find below a calculator to easily calculate your maximum herat rate based on your age …
the calculations do change over time and everyone is different….so again this is just a guide and not an absolute…
but getting your heart working, and being used ot pumping at a higher rate, should be a measured appraoch – rather than saying i need ot get my pulse up to 90% and keep it there for 5 mins……you would need a cup of tea after that…..
so put your age in and see where your target heart rate is for mild and strenuous exercise…
then go out and buy a heart rate monitor for the wrist, finger or chest and see what you do next time you exercise.