This makes people able to drink more coffee without making them hyper or jittery.' Coffee also affects people differently depending on how often they drink it. Regular coffee drinkers tend to be ...

If you love a cup of joe but don't want the jitters, decaffeinated coffee is ... as well as more recent information on how much coffee we drink — just consider the different sizes now available ...

So, you feel more alert and your blood pressure and heart rate increases [when you drink coffee]. “In the right circumstances this can be very useful. However too much and you can feel jittery ...