Alston Keith Jr. celebrated his 40th birthday by running 40 miles. He ran 50 miles on his 50th birthday.

Now, to mark the occasion of his 60th birthday, the Selma attorney plans to up the ante one more time by running 60 miles. In one day.

He’ll start at midnight tonight (which in itself would be a challenge for many sexagenarians) at Memorial Stadium and plans to finish &uot;I hope by noon Friday.&uot;

If he survives, family and friends plan a toast and a roast in his honor at Brownstone Manor from 6 to 9 p.m. Sunday.

Keith began running back in 1979 to lose weight. &uot;I was up to about 185 and I wanted to take off a few pounds,&uot; he says.

Always health conscious, Keith claims he hasn’t missed a single day of work due to illness. He can’t remember being sick a single day of college, either. &uot;I’m very healthy,&uot; he says modestly.

Today, he maintains his weight at a svelte 158 pounds.

Sunday, he ran 30 miles as a sort of tune up for the big day tomorrow. Afterwards, he went to church and otherwise resumed what he calls &uot;my normal activities.&uot;

Keith says he has entered 26 marathons and completed all but one of them. He usually finishes at around three hours, a respectable time for men half his age. He has run all the name marathons, from New York to Boston to Chicago to Honolulu. In New York he was one of 28,000 participants.

He attributes his one failure to complete a marathon to poor preparation. &uot;I don’t think I trained adequately,&uot; he says, frowning slightly.

As a marathoner, Keith says he has experienced &uot;the wall,&uot; that mythical barrier of physical exhaustion that strikes virtually all runners who make it to the 20-mile mark of a 26.2 mile marathon.

Unlike some runners, who experience shin splints and other painful ailments, Keith insists he rarely suffers any ill effects from his running. He explains, &uot;I have a natural footfall.&uot;

He explains his dedication to running as &uot;a way to use up nervous energy.&uot;

Keith says he hasn’t missed a day of running since 1979. It is, he concedes, &uot;sort of addicting.&uot;

Barring any unforeseen difficulties with his 60 at 60 run, Keith already is making plans to run 70 miles on his 70th birthday.