Two AD5933 bioimpedance analyzers connected to human body (both the arms)

Hi everyone,

I have used two Ad5933 evaluation boards to collect impedance data from both the arms of human body. I have acquired data in time domain fixing the measurement frequency at 50 kHz.

However, I am not quite sure about the reliability of my data as I getting a repetitive spike pattern (see the figure) in my data. When I am using a single device this did not happed.

What would be the reason for this scenario?