If you can't hold a conversation, you're going too fast for an easy run.
Here is the thing nobody tells you when you start: most of your running should feel slower than you think it ought to. Not a bit slower. A lot slower.
The reason is that easy running and hard running do different jobs. Easy running builds the parts of you that take months to change — the capillaries feeding your muscles, the mitochondria inside them, the tendons, the bones, the sheer habit of being a person who runs. Hard running sharpens what you already have. You cannot sharpen what you have not built.
How easy is easy
The talk test settles it. If you can speak a full sentence without gasping, you are in the right place. If you can only manage three words, you are running a tempo session and calling it an easy run.
Most people find this humbling. You will be slower than you expect, and on the hills around Yerevan you may end up walking a little. Walk. Nobody is watching, and the run still counts — we settled that in March.
The split
A rough rule that has held up well: about four fifths of your running easy, one fifth hard. If you run four times a week, that is three easy runs and one where you actually work.
The trap is the middle. A run that is too hard to recover from but too easy to improve anything is the least useful run you can do, and it is the one most beginners do most often. It leaves you permanently a bit tired and never quite fitter.
What it buys you
Run easy on the easy days and the hard days get genuinely hard, which is the point. You also stop collecting the small injuries that come from never being fresh.
If you want a number to run to rather than a feeling, heart rate is a better guide than pace — especially here, where nothing is flat.