PPG sensor data via Arduino - Baudrate v/s sample numbers


I made a ppg sensor and acquiring the data from it to my laptop via Matlab - Arduino Uno interface.

I had been changing the baud rate in the arduino code available from mathworks package and also the

corresponding matlab code. I made the following observation:

Baud-Rate Samples/sec

1200 6 2400 12 4800 24 9600 30 38400 30 115200 30

So what I observe is the saturation in number of samples/sec from 9600 and later.

Suggestions regarding this are requested.