What training program to find maximum heart rate?

The only real way to determine your max HR is the painful way - do something that gets you there.

Outside a lab test, hill repeats are probably good.
After a decent warm up, run hard up a hill that takes at least a minute.
Does this a few times and observe what HR you get. Should be close to your max.

What you actually get can depend on how tired/fresh you are (generally if you are tired won't get it up so high) and how warm it is (tend to higher HRs on warmer days) and indeed how hard you actually try.

You also can get pretty close to max HR at the end of say an all out 5K race.

The only real way to determine your max HR is the painful way - do something that gets you there.

Outside a lab test, hill repeats are probably good.
...
You also can get pretty close to max HR at the end of say an all out 5K race.

Lol, I knew you were gonna say that about the painful way :) (So I was prepared ;) )
I live in the Netherlands, unfortunately it's about the flattest part of the planet so no hills around in a 250km radius...
But an intensive 5km run giving all I have I can do.
Any rules on how to read the max? Just take the highest value my watch shows?

How do you guys know your maximum heart rate?

From reviewing the heart rate statistics from my activity records.

Do you use the 220-age formula?

Definitely not. The formula gives me a maximum heart rate of 175, and I exceed that on most runs that are faster than a jog.



In my Garmin Connect user profile, I've set my maximum heart rate to 186, based on past efforts last year when I was less fit.

But I have no clue what's a reliable workout to get a more accurate heart rate setting myself.

I think you can do without the impact on your bones and joints if you're only trying to give your heart a maximal effort workout, so I'd suggest tracking your HR while using an indoor bike, starting with five to ten minutes of warm-up at a cruising speed, then increase the resistance in steps every three minutes or so while keeping the speed steady over the next fifteen to twenty minutes – or until you can take no more. The resulting HR graph will probably be less subject to spikes (than, say, running uphill and downhill repeatedly), and you can see at which level it plateaus.

Ah, I didn't notice the Reports feature on Garmin Connect, that's a nice way to see your stats!

Here's my stats (only have the watch for 10 days now :) )
2017-03-12 171 bpm
2017-03-15 193 bpm
2017-03-17 171 bpm
2017-03-19 162 bpm
2017-03-20 176 bpm
2017-03-22 174 bpm

220-age gives me 177, in none of the above wokoutouts I gave it all I had.
The 193 is a bit of a lonely spike during that workout, not really trusting that.
I'll see what a heavy 5k next weekend will bring me.

you probably want to use a HR strap if you can beg/borrow/steal one. Otherwise you might get some spikes.

Otherwise you might get some spikes.

Thanks for mentioning that. It just occurred to me to look at the activities with the highest HR recorded lately, since I've moved to an FR630 five weeks ago and aren't expecting any spikes… and it turned out that my activities have been ‘contaminated’ by entries from my old FR235, which my girlfriend has been using in that time, when I charged the FR235 with my Mac the other day using the USB docking cable, even though I've removed the device from my Garmin Connect account and she registered it against hers.