Yesterday I continued with the 2min.run-2min.walk X 5times.
In that second day I felt i could regulate somehow better the pace and sync it with the self-assigned 70% of my max- 145bpm. Yet it is quite hard altogether. Does anybody know a sure way to accurately ascertain my max. heart rate? I would not like to pay for a treadmill test, but maybe the National Health would? ;-)

Hill sprints...? Find a relatively steep hill perhaps 200m long? and run up it 5 times hard, jogging back down each time, the last time should be completely flat out to the point where you honestly feel like collapsing at the top.

That's about as close as you'll get to finding out your max HR... Is it actually ever possible to find your max HR? surely if you were to exceed your 'max' then you'd die - so you'll never really know? Just a thought... lol.

Thanx Richard! I once made that test but I probably didn't push myself hard enough, for the max. rate I reached was 172. Theoretically and using the typical formula of substracting my age to 220, my max is about 180, but using the formula by John Parker in his book HR Training, it would be something like 185. I'll do the hill test again. :-)

I've done the hill test myself and found it hard to reach my max HR... I could feel that my legs were the limiting factor and I only reached 187bpm, whereas before that I'd managed 197bpm on the bleep test.