Hey L.A. Marathoners: Don’t forget to change the clocks!

Runners have spent months training for the moment when the Los Angeles Marathon begins Sunday morning at Dodger Stadium. But the most important moment of preparation is still to come: Remembering to set their clocks forward Saturday night before they go to sleep.

For the first time, the Los Angeles Marathon is being held the same weekend that the nation is asked to move the clocks forward one hour and lose an hour’s sleep as part of our daylight saving time tradition. (Remember: Spring forward, fall back.)

It has the potential to wreak havoc on the 25,000 runners and joggers, walkers and woggers who will line up Sunday morning for the sold-out race. If they oversleep -- due to a buggy smartphone, a bobbled alarm clock, a missed wake-up call, whatever -- they are out of luck.

Tracey Russell, the marathon’s chief executive, told the Los Angeles Times on Friday that marathon officials have been doing everything possible to get the word out to competitors: “Remember to set the clocks forward an hour.”

She added: “We’ve really been messaging about this for the last two or three months,” she said. There will be additional reminders via social media, and at the expo before the race, as well as on official race material. “We’re doing the best we can to make sure they set their watches, their alarms, everything they have, an hour ahead, so they don’t miss the start.”

Russell said staging the race on the weekend when the nation tweaks its clocks was not ideal, but it was the best date possible given competing events that bring tourists into the city and gobble up hotel rooms.

So, what happens if someone does miss the message and arrives late at the starting line?

“Unfortunately, if people are late they are probably not going to be able to run with us this year,” Russell said.

That’s because race organizers must reopen city streets to through traffic at pre-designated times. Here’s a look at the race course, which runs from the stadium to the sea in Santa Monica.

Her final bit of advice: Competitors should “set their watches, their alarms, everything they have, an hour ahead, so they don’t miss the start.”

After all, you don’t to be like “Seinfield’s” Jean-Paul, right?

Are you racing Sunday? Tweet me @renelynch so I can cheer you on!

ALSO:

How the West was won: Animated map

Infographic: How often do we say “dude”?

Dove kills ad calling New Jersey “The Armpit of America”