Inserting time in spreadsheet

[papabill]

I have a spreadsheet that I keep track of my blood sugar levels (I'm a diabetic), and it's set up like this:

Date                   Blood Level    Time              Blood Level    Time                          Blood Level    Time                          
Sun-Dec-09		242	      7:30 AM		206	       1:21 PM

Each time I take my blood sugar level, I must record the level and the time. The level fluctuates, but the time has to be entered manually. I have tried =now() as the time, but every time I open the spreadsheet, anything in the =now() changes to the current time. I need some way to automatically enter the ACTUAL time and keep it from changing.

Does this make sense? And, can anyone help me?

Thanks