Thanks for contacting us with your question. I have a few questions for you.
You say you have been training consistently for 6 years with no improvement. What have you been doing for training?
Do you use strength training?
How are you determining the intensity zones you mention? Z1<140. Z2 < 150 etc?
Nose breathing only works well for those with a good history of aerobic training. That is why 162 feels too fast.
When I run flat to keep my HR low I have to go very slow and is not much difference between zone 1 or 2, feels super slow and easy. But as soon as I start going faster or uphill my HR goes up super fast above 160 so I am avoiding uphill to keep my HR low.
This is typical for people with aerobic deficiency syndrome. Please read this: https://uphillathlete.com/what-is-it-that-enables-endurance/
I have been reading the forum and I don’t know if I am doing things right. I wonder if I have the ADS.
Yes I am pretty sure you have ADS. You should do all aerobic training in Z2, close to your aerobic threshold.
I don’t know if I should keep on running at that pace or should I go faster or should I go easier.
The only way to fix ADS is to train a lot in the aerobic zones 1 and 2
Should I keep on running that amount of hours or should I increase the amount of time? (I can train as many hours a days as it is needed, as long as it helps me to improve).
Duration is the biggest stimulus to aerobic adaptation. The more hours you spend in these zones the bigger the training effect. If you can train more hours in Z1-2 you will see greater improvements.
I hope this helps.