Part of the show Naked Science Question and Answer
Kate in Harlow asked:
Can you please repeat how many tonnes of blood the heart pumps in twenty four hours.
The heart pumps around fifty times per minute. It pumps about five litres of blood a minute. So if you times that by sixty for the amount of blood in an hour and then times it by 24 for the number of hour in a day, it's about 7500 litres of blood every single day. Blood is about 1 gram per centimetre cubed, which means it's a thousand grams per litre. That means that if you pump 7500 litres in a day, that's 7.5 tonnes of blood pumped around your body every single day.