sensing body impedence

Hi, I am a beginner in electronics.
I am trying to sense body impedance for gesture detection from this project.
Touche-for-Arduino-Advanced-touch-sensing

I can detect every other object but cant get it work with hand.
I connected the input signal to one hand and ground to the other. But my graph becomes somewhat straight line like this.

Is the voltage supply less or am i connecting the wrong way.

I mostly work on programming, so getting in electronics is tough for me :confused: .

graph.jpg

FR73R4DH2MYISBD.LARGE.jpg

Do explain more on what you're actually trying to do, as it's clear as mud to me.