First: the voltage of your battery will most of the time be lower than 3.7V so you're really at or under the specified limit for the HC06 module. You better find a Bluetooth module that's designed for 3.3V.
Okay I agree but I am currently powering the Bluetooth module with USB power anyways which is currently about 4.3 V
Some platforms and members, do not like going off forum to get code or images.
Sorry Tom but my code was too long and I wanted to provide the people in the forum with the full code.
To quote the adafruit site;
Good point. I have noticed that the SD might not be the problem. When I do not use my new heart rate module (MAXREFDES117), everything seems to work and the time and date display properly. Now , theres a complex peak detection algorithm going on in the background. Could this be disrupting the UART interface between the mcu and BT
Library: GitHub - sparkfun/SparkFun_MAX3010x_Sensor_Library: An Arduino Library for the MAX3015 particle sensor and MAX30102 Pulse Ox sensor