Report "My heart rate monitor wristband is about 4 years old. I just bought a new transmitter and chest strap about one year ago. I am noticing that during a workout, the readout on my wristband is showing very low numbers from time to time. Today, it was even showing 0 for quite awhile. Then, it appears to become fairly normal again. This is a new problem. I am wondering if a battery needs to be replaced or if I need another new transmitter"