What causes your resting heart rate to increase from a normal 50 beats per minute to over 70 beats per minute?
you probably have some type of arrhythmia. You need to go to the doctor?
Yes I agree with heart increases rate it can range from
exercising which is normal your heart should beat faster if you are exercising but not to fast.
Theme park rides
Sometimes bradycardia is normal. For example, healthy young adults and well-trained athletes often have resting heart rates of less than 60 beats per minutes."
The answer to what causes increase could be if you have just exercised or are anxious, stressed, turned on. If your heart rate increased from 50-70 whilst still resting then it is not regular & you should see a doctor. 50 beats per min is not average, but it could be ok for you depending on whether you are an athlete or perhaps hereditary reasons.
If he is an athelete it is normal finding unless backed by Holter's monitor.New range is 60-90 BPM.