HR crosses MAF MAX HR zone during incline - Upto what % of run duration this is ok?

Hi, thank you for explaining MAF in very simpler way. After reading the blog, I have started MAF. When i started, my MAF Test pace was 09'30''/Km which is now around 08'10''/Km. What bothers me is that I live in area with incline n hills where my HR shoots up beyond MAF MAX HR Zone for few mins. I see that my tracker records on an average, 10% of the time above MAX HR. I'd like to understand is there any benchmark to what % this is ok, what i understand from blog is that it should be 100% within MAF limit; however it's challenging to run close to MAX HR and not crossing MAX HR Zone during incline.

Thanks.

Nicole's reply:
Normally you would stay within your MAF heart rate zone throughout the duration of your run.

You don't say how long that you have been doing MAF training but it is clear that you are making good progress which is great. Once you have been doing MAF training for 4 - 6 months (base building) and have started to plateau, then it is ok to add some time where you go over MAF, usually in the ratio of 80/20 (80% below MAF and 20% above MAF). Every year try and go back to doing the base building phase whereby you stick purely to MAF for a few months.

I too live in a hilly area and to start with I was crawling up the hills. I have improved over the years but I still have to walk some of the hills.