For many people, running a few miles a day is a challenge. For Steve Knowlton , a few miles is merely a warm-up.

Starting June 1, the Prior Lake native will begin the journey of a lifetime -- running an average of 70 miles per day, for 45 consecutive days across America from west to east -- in order to break a world record. Incredibly, this will be his second run across the country.

Knowlton, 46, will run to raise money and awareness for Asperger's syndrome, a high-functioning form of autism. All funds he raises will be donated to Asperger's Network Support (ANSWERS), a Minnesota-based support network that advocates for research, education and assistance for families living with Asperger's syndrome.

In order to break the record, previously set by Frank Giannino in 1980, Knowlton will force himself to run about 5 miles per hour in order to keep up the vigorous pace. He will depart from San Francisco and plans to arrive in New York City on July 14, after running roughly 3,100 miles.

Knowlton, who has completed 46 marathons and seven ultramarathons, in 2010 ran alone from Seattle to Key Largo, Fla., in 100 days, averaging 37 miles per day and pushing a jogging stroller he estimates weighed 100 pounds for the majority of the trip.

Pushing the stroller convinced him he could break the record by running an extra 20 to 30 miles per day without it, so long as he has a crew to take care of his diet, nutrition and lodging needs. Knowlton estimates he will pound the pavement for 14 to 18 hours a day and burn through 12 pairs of shoes. He plans to eat whatever food is available along the way, whether it's fast food, gas station snacks or a home-cooked meal courtesy of the kindness of strangers. During the last run, he survived on the likes of oatmeal cookies, Snickers bars and 5-Hour Energy shots. He expects to drop a significant amount of weight.

"I by no means take this run lightly," he said. Knowlton said he takes on a "militant" mindset when he runs -- essentially, he doesn't think about running.

Because it's his second trip, Knowlton says he knows what to expect this time around -- "somewhat."

Knowlton, who often trains on County Road 42, says he talks to God to pass the miles and frequently finds himself relaxing, daydreaming or thinking about the future.

"At one point, when I was pushing the stroller, I found myself snoring," he said. It's not unusual for him to forget what the scenery looks like as the miles fly by.

Although he expects painful shin splints, intense heat, extreme weight loss and pinched nerves (he couldn't feel his toes for almost a year after the first run), Knowlton says he will refuse any days off.

"Once you stop, it's really hard to get started again," he said. "Your body gets used to relaxing."

Even when he finishes the run, like many runners he expects to battle major depression due to a sudden stoppage of endorphins that are released every day from the exercise. Despite all of this, he says his passion for his cause will keep him on the road.

Knowlton has loved ones close to him who suffer from Asperger's syndrome, a disability he admits he once misunderstood.

"I would think the person [with Asperger's] was being disrespectful, as far as not making eye contact or having any interest in what I was saying," he said. On the contrary, people with Asperger's are constantly dealing with "sensory overload" from the surrounding environment, said "ANSWERS" co-founder Theresa Gustafson. Her own son was diagnosed with Asperger's in 1997. Situations like going to the grocery store were once very difficult, she said. "The sights, smells, lights and sounds were just too overpowering for him."

Gustafson is working on securing an RV for Knowlton to sleep in, finding running clubs to accompany him along the way and setting up speaking engagements.

"He's more than just a banner-waver," she said. He exemplifies the struggles and triumphs we go through every day, she said.

To the many naysayers who call the endeavor impossible, Knowlton pays no heed.

"I think people, they limit what human beings can actually do. I think you'd be surprised what the mind can do," he said. "I know it's going to push me to the edge mentally and physically, but I think it's going to be worth it in the end."

Ashley Bray is a University of Minnesota journalism student on assignment for the Star Tribune.