I've never had an easy time getting eight hours of sleep each night. But, then again, it's never been a huge problem for me. I'm always fully alert and active throughout the day. What changes, seemingly at random, is how early into the evening I run out of juice. And then I got an Apple Watch and finally understood why that is.

I learned fairly quickly that how much sleep I'm getting (or not gettings) isn't what's important. It's how much deep sleep that I'm getting. If I get nine hours of sleep... ten hours even... it doesn't mean anything if I get under three hours of deep sleep. I'll be a wreck the next morning, get through the day okay, then have zero energy for anything except vegging out on the couch all night. On the other hand if I get four hours of deep sleep, I will be fully rested and have a full day of energy even if that's all the sleep I get.

For the past six months I did an analysis of what I eat, how much I eat, and when I eat it. I also kept track of how much deep sleep I got. The results were interesting.

Turns out that, for me, there's a simple checklist that gets me the best possible deep sleep...

• No caffeine after 1:00pm
• Light dinner before 5:00pm
• No food or drink after 6:00pm
• In bed by 10:00pm, and lights out by 11:00pm

If I stick to that schedule I'm usually asleep between 10:30 and 11:00, and wake up between 5:30 and 6:00. This usually results in six-and-a-half to seven hours of sleep with four hours of deep sleep. And that's my happy place for being well-rested.

Last night, for example, I was in bed by 10:30. Turned the lights off at 11:00. Fell asleep at 11:33. Woke up at 5:46. This got me 6 hours and 13 minutes of sleep. But 4 hours and 21 minutes of that was deep sleep, so I was absolutely golden all day long.

All this time all I need to do was to not worry about whether or not I was getting 8 hours of sleep and shift my eating to earlier in the day. Simple.

And do you know what happens if I stay up late drinking or eat dinner too late or have too big of a meal or drink caffeine after 1:00? If I'm lucky I'll get three hours of deep sleep. But usually one or more of those factors will result in my getting less than three.

And there you have it.

Took me 30 years to get here, but at least I've finally arrived.