Coffee/caffeine acts in a strange way. It causes the blood vessels to expand, which then enables more blood to be pumped through with less effort (like descaling the pipes). This makes the nice, oxygen rich blood get to the parts that need it, thus making things more active, including the brain. Cola has the same effect, if it has caffeine in it. So do red wine, chocolate and ginger beer, but don't ask me how or why they do!

This is great if you have a sluggish system. If you don't then it's instant migraine as the brain gets more than it can cope with and it goes into overdrive. If you do have a sluggish system then it will quite often cure a migraine (personally, I get the second sort. A good strong cup of coffee at the right time and it's gone. I also 'use' coffee when I'm having an asthma attack, it gets rid of that 'bra four sizes too small' feeling), and keep you alert. But it's short-lived, so you need to keep everything lubricated whilst it's 'open and ready'. So when your throat appears to close after a coffee, it's really the surrounding blood vessels expanding - the throat and other spaces reduce a little to make room for this expansion.

Biology lesson over. Your homework this weekend......

LTS