Blood pressure - quick question

[AllTheShapes]

Well, two questions:

Which is the important number in blood pressure? The number above or below?

I was admitted to hospital and bed bound for a while, my "bottom number" (bp ) was 68 consistently. However any other time I've had my bp taken at appointments etc it's been 75-85. Why may this be the case?

I've googled but I'm not sure I understand the answers the internet gives me !

Both numbers are important, the top number is the pressure exerted on your blood vessels when the heart is contracted and the bottom number is when it's relaxed (in a way, but that's the easiest way to explain it). The top number (systolic pressure) is the one generally used for deciding whether to treat high or low BP though. Your blood pressure changes all the time so variations in readings are completely normal and can be affected by all sorts, temperature, hydration, exercise...

Whether you're lying down or not can make a difference too - I think it being lower if you're in bed would be quite normal.