Dr. Zab Mosenifar, professor and executive vice chair of the Cedars-Sinai Medical Center Department of Medicine, is a man of routines. He has spent his entire career at Cedars-Sinai, lived in the same house for 39 years and runs every day – rain or shine, without fail or exception.

Cedars-Sinai Medical Center’s Dr. Zab Mosenifar ran his 100th marathon Saturday, March 9, on Catalina Island. Mosenifar, 70, has run more than 135,000 miles. (photo courtesy of Cedars-Sinai Medical Center)

“I don’t remember a day I haven’t run in the last 50 years,” said Mosenifar, 70, who also serves as the Geri and Richard Brawerman Chair in Pulmonary and Critical Care Medicine and as medical director of the Women’s Guild Lung Institute.

On Saturday, Mosenifar ran his 100th marathon – the Catalina Island Marathon, rated the sixth toughest in the world, on a rugged course he had already conquered 37 times. By the time he completed this latest marathon, Mosenifar had run roughly 5.6 times around the Earth, a total of about 135,200 miles.

“Only my last car had more miles on it than my own knees,” said Mosenifar, although he admittedly shares that he has only owned three cars in his entire life – all black Porsches – that he drives until they can be driven no more. “I’m frugal.”

The same cost-saving approach comes into play when buying his running shoes, the biggest expense in his life. Mosenifar, who puts about 450 miles on each pair of shoes, shops various online retailers to see if his favorite brand, Hoka, is on sale.

Mosenifar laces up his Hokas by 5 a.m. each day, then he’s out the door running in the Santa Monica Mountains. Monday through Thursday he runs six miles. On Fridays, he’s alongside a group of men he’s trained with for years and runs eight miles. On the weekends, he goes 11 to 12 miles – a total of 50 miles per week.

After each run, Mosenifar enjoys a cup of black coffee and half a bagel. He’s in his office at Cedars-Sinai by 7 a.m., and by noon he’s sipping on vegetable soup for lunch. Without fail, he takes an espresso break at 3 p.m., using the same yellow mug his daughter – now 30 – made for him as a young child. And for dinner every night, Mosenifar enjoys a dinner of pasta with pesto and a salad with his wife of 35 years, though she eats a different meal altogether.

“I use running not just for my own solitude, but as a tremendous release of stress from work, because there can be some really tough, sad days,” said Mosenifar. “I am disciplined. I am not someone who will have a few drinks. I go home and go for a 10-mile run, even if I already ran in the morning. That’s my bar. That’s how I try to get over some of these stresses of my life.”

Before Saturday’s race, Mosenifar said he wasn’t focused on the milestone number of 100 completed marathons.

“I’m more impressed that I’ve been able to run all of these years,” said Mosenifar.