pulse sensor + Arduino + ESP 8266

i doing the heart rate monitor by getting the heart rate from pulse sensor and send through the internet website using ESP 8266 .I found that the pulse sensor value is not accurate (200BPM) when i connected the ESP 8266 and the value become normal when disconnected the esp8266 from supply.What problem will causing this happen ?

Post the code you are using, a link to the pulse sensor, and a schematic showing how it is all connected together for optimal assistance here. If your pulse rate really reaches 200 then also consider consulting a doctor.