Shell script - Sudo-permissions lost over time

I've made a simple bash script that need to keep it's super-user privileges throughout the script. Unfortunately, but understandable the script looses its sudo-eleveted permissions when the sleep occurs. Not good for me:

sudo echo "I am sudo!" # Asks for passwords
sleep(60)
sudo echo "I am sudo!" # Need to enter password again.

I thought about replacing the sleep with a while-loop that keeps the sudo alive, but I am pretty sure that there's better options available to make the sudo-permissions stay throughout the script?

Thanks