Waking arduino from sleep by touching a button

Ey up!
I am trying to design a circuit which i can wake up from sleep by issuing an interrupt. I would really like to be able to achieve this by simply touching a button rather than having to press it(which would be simple).
I thought about using cap touch but this would require me to routinely wake from sleep to test whether the button is being touched which would greatly increase power consumption(its a battery powered project).
Can anyone think of another way which would allow me to wake to arduino from sleep? I thought about using a transistor to amplify the signal from my finger(if the button was conductive) but this would require the finger to bridge 2 terminals(one supplying current and one connected to transistor base). Any help would as always, be very much appreciated. Thanks!

Couldn't you simply have the Arduino code sitting in a "while" loop?