"If you wake up at 3 o'clock in the morning and you're wide awake, do not put on the television," triple Major winner Harrington warned at Riviera Country Club on Tuesday.
"That is the golden rule, do not put it on. Just lie there and look at the four walls, but the minute you put on the television, that's it. You ain't ever getting back to sleep."
The globe-trotting Irishman knows all about the potential pitfalls of jet lag, his most recent run of tournaments taking him to Singapore, Hong Kong, Dubai, South Africa, Abu Dhabi and then Arizona and California over the last four months.
Asked how he managed to shake off the effects of such a dizzying itinerary, Harrington replied: "You feel it if you're not working. So jet lag and travel, it's harder (to deal with) when you go home and you don't have a time scale to stick to.
"I've got to make an 8.10 am pro-am time tomorrow, so I'm getting up probably 2-1/2 hours before that. I've got to make a 7.50 am time on Friday, so I'm getting up three-and-a-bit hours before that time. I just have to get up and get on with it.
"One night's sleep deprivation has no effect on performance whatsoever. Two nights is extremely detrimental. So I know no matter how bad I sleep or how bad I feel, I can get through a round of golf. I can last that length of time. I'll be fine."
Harrington, known for his workaholic approach to the game, also recommended plenty of gym time to keep jet lag at bay.
"Getting into the gym always gets you back on track," said the 41-year-old, who is playing his fourth consecutive tournament at this week's Northern Trust Open at Riviera.
"That's probably one of the keys. We'll all do that. We'll all wake ourselves up by going to the gym. And there are other simple disciplines, being professional in the sense of hydrating and eating properly.
"If it's really bad, it just means you have to maybe curtail (golf) practice and catch up on your sleep."
Harrington, a five-times champion on the US PGA Tour whose most recent victory came at the 2008 US PGA Championship, will tee off in the company of Argentina's Angel Cabrera and Canadian Stephen Ames in Thursday's opening round.
- Sports & Recreation
- Riviera Country Club