What is the normal heart rate of a 26-years old women?

It depends on how hard you want to exercise. Basically take 220 minus your age. That is your max heart rate. Then you take a percentage of that to determine your training heart rate (THR). Usually 30-50% is considered the "fat burning" zone and 60-80% is you "cardio" zone. For example: 220-26 = 194, your max heart rate If you want a good cardio workout, take 80% of that: 194 * .8 = 155.2, your target (training) heart rate As a rule you never want to exceed 80% of your max, but if you are on a machine and constantly monitoring your heart rate you will see it fluctuate quite a bit, especially if you are doing intervals.