Why do I feel tired if I drink (too much?) coffee?

[MagicalTrevor]

I usually drink coffee whilst at work but normally find myself feeling quite tired towards the afternoon and then into the evening.
The last couple of days I've really cut down and today had just one coffee (instant rather than the 'bean to cup' stuff in our machine). I feel great compared to how I sometimes feel if I've had quite a bit of coffee.

The problem is that, previously, to combat the tiredness I had another coffee. It's now obvious that this wasn't the best thing to do!

So why does my body react to coffee with tiredness when you'd surely expect the opposite!?

[TheEnd]

Although I'm not sure if it is medically correct, the idea is that the caffeine makes you burn up and use all of your energy reserves, so whilst you are burning twice as bright, you are running out of wax...

[MagicalTrevor]

TheEnd said:

Although I'm not sure if it is medically correct, the idea is that the caffeine makes you burn up and use all of your energy reserves, so whilst you are burning twice as bright, you are running out of wax...

Ah makes sense! Maybe I should cut down on the coffee then!

[MarsellusWallace]

I have a similar reaction with Red Bull.After I drink a can I could fall straight asleep,but after about an hour of feeling tired it starts to kick in.

[bazking69]

I drink decaf instant now as I was always feeling tired and lethargic on 'proper' coffee, and I do drink alot of coffee...
I feel much better for it.