[tweezy]

Alertness early in the day seems to do the trick for me. I think of deep sleep as reaction to how alert I was earlier in the day. So on days I make an effort to activate myself early in the day, I will fall into longer deep sleep that night (2+ hours according to my fitbit). If I just kind wake up and laze around the house without getting much activity, then I I get under and hour of deep sleep, even with the same amount of total sleep.

What seems to work for me is immediate sunlight exposure right when I wake up, 5 - 10 mins of being outside, 16 oz of cold water right around that time, 2-5 mins of an activity that gets my heart rate up (jumping jacks, burpees, jump rope). If I can muster it, a cold shower also helps.

There are other things like getting exercise, avoiding caffeine after a certain time, avoiding light exposure prior to bed, avoiding alcohol, sleeping in a cool room that I think also help. But for me it's the making myself super alert right when I wake up that has the biggest bang for my buck.

This is anecdotal, n = 1 kind of stuff though. And I don't do it every day, and it doesn't work 100% of the time. But I definitely notice that I am far more likely to get a lot of deep sleep when I do those things than when I don't. Hope it helps you in some way.