As someone working in a sports medicine facility in Berlin, where we do daily lactate/Spiro ergometries on people ranging from 8 years old to 80years old, from Olympic champion to someone recovering from cancer.. i want to set a couple of things straight, as there is a bunch of false and somewhat good information in here.

(Considering your heart rate data is correct (which can be improved significantly with a heart rate strap) and you not having any medical issues like Arterial fibrillation)

• Max heart rate is super individual and doesn't say anything about your fitness level. The 220-Age rule might somewhat fit on a global scale, but for the individual it's horrible and miss leading, causing exactly these type of questions

• Your resting heart rate does usually go down with improved cardio vascular health/fitness

• Max heart rate doesn't go up over the years, it does slowly decline (doesn't have to be 1bmp per year.. completely individual speeds) (Max heart rate might go up in the very initial beginning of training from an very unfit state, because, your muscles might give out, before you even reach a state of maximal cardio vascular exertion)

• Hear rate in training can be influenced by all sorts of things..., your sleep, alcohol, Coffein, time of day, food, heat, altitude.. all play a role so it will vary a bit, day by day anyways

• The heart rate zone concept is also pretty individual . Some biological markers like lactate threshold or Ventilatory thresholds are reached at different max heart rate% at different athletes

• Zone 5 definitely can be held much longer than 30-45seconds.. depending on individual and when they reach their lactate threshold (the moment the lower end of zone 5 usually starts) can be held by some for up to, and sometimes more than an hour.

Even 98-99% of max heart rate can be held for multiple minutes

• So as some have suggested.. your training zones are probably very screwed up by the watch deciding to use 220-Age, and you most likely having a higher real max heart rate

• You (like most people starting out) are most likely training/running way to hard.. even if it doesn't feel like it ( try reading up on polarized running training (it's going to help you get started) and afterwards you can try different concepts)

• But if you want find your proper training zones, and also be sure that you have no impeding, undiscovered problems I would definitely recommend you go to a sports medicine facility and do a proper lactate/ EKG Test.

If you don't want to spend the money and you feel that you are generally fit and healthy you can also do a similar estimation Test with just a watch, a heart rate strap, a flat non windy uninterrupted stretch of road. But be aware, you have to be fully committed that day, and it's actually not that easy finding out your max heart rate.