Your heart was racing the other day when you were working out. Was that a problem? Was it going too fast?
You are asking about the maximal heart rate that you should not exceed when you exercise. This of course depends on your age and whether you are in good health. There are of course certain medical conditions when the heart beats too fast even when you are not exercising. If this happens to you don’t delay. Get immediate medical attention.
Now assuming that you are in good health and wondering what should be your maximal allowed heart rate, there is a formula that is posted everywhere at gyms and on exercise equipment. It is to subtract your age from the number 220. The answer is your maximal allowed heard rate. For example if you are 40 years old, your “magic number” is 220 - 40 = 180 beats per minute.
This formula was developed in 1968 and was based on the data from 10 published studies performed between 1938 and 1968 The problem with this formula is that it over estimates the top level of exertion for younger people and that it underestimate the level for older people. In general terms exercise is targeted to a percentage of your maximal heart rate, Moderate exercise intensity is 50% to 70% of maximal Vigorous exercise is to% to 85%.
A simple gauge of exertion is the talk test. Exercise until you find the point where you have difficulty talking. Back off a bit from that pace slightly and you have your optimal maximal exercise level.
Go for it but don’t overdo it.