It is completely normal for your heart rate to fluctuate between 83 and 98 beats per minute, even while taking Corbis (bisoprolol). Our heart rates naturally shift constantly throughout the day due to simple things like deep breathing, minor movements, hydration levels, or even slight anxiety while watching the monitor. Fingertip pulse oximeters can also show brief, normal variations. Since your cardiologist has already confirmed that your heart tests are completely normal, you can feel very reassured. This minor variation is a healthy, natural sign of your heart responding to your body's needs. Please continue to take your medication as prescribed and share any ongoing worries with your doctor.