I'm wondering if it's normal for my heart rate to go up to 150-160 when I'm doing cardio at the gym or climbing stairs, and then drop to around 110 when I go for a walk. I've had several ECGs done and just had an echo two days ago, and everything seems fine. My resting heart rate usually falls between 55 and 100. Should I be concerned about these numbers?

It is normal for your heart rate to increase during physical activities like gym cardio, climbing stairs, and walking. Your heart rate of 150-160 during intense exercise and 110 during walking is within a normal range for physical exertion. Since your ECG and echo results are normal, there is likely no underlying heart condition causing these heart rate variations. It is important to stay hydrated and listen to your body during exercise. If you experience any chest pain, dizziness, or fainting, please stop the activity and seek medical attention.