Working out what you heart rate should be when training is kind of like asking someone how to look after a baby, you get lots of answers and everyone thinks they’re right, but you need to figure out what works for you and your body. Some people say that training at a less intense level for a longer duration helps your body to get fit without putting too much strain on the heart, others say if you don’t push really hard then your body is not going to adapt and you are not going to get fitter.
You need to find some advice from someone you trust and then try it out, if you find that getting your heart rate up to 80% of its maximum doesn’t seem to be doing you much good, and you are just tired all the time and get lots of injuries, then try something else, eventually you will find something that works for you.Calculating your maximum heart rate is just as tricky, there are all sorts of different formulas out there from different researchers, so I just simplify it and use the formula probably everybody knows, 220 – your age.
It might not be the most accurate, but then it might, as there is so much confusion about how to calculate your maximum heart rate then I will leave the scientists who came up with them to argue over that while I get out there training!
As a general rule of thumb then 60 – 70% of your MHR (max heart rate) is considered to be gentle aerobic exercise which gets your heart working and helps you burn fat. 70 – 80% is what most people consider to be working hard and so you are building up your stamina, 80 – 90% is getting away from aerobic exercise and into anaerobic exercise where your body cannot get enough oxygen and you build up lactic acid. 90% and above is running for your life from a pack of hungry lions and not recommended for most people for more than a very short period of time!
I’d advise starting off more gentle and then work your way up based on what you feel comfortable with and what results you are getting, start off at 65% for 2 weeks, then increase in increments of 5% until you find your perfect training heart rate and your perfect recovery heart rate (for those days where you just want to do some light exercise).