Dennis Beggs did his first marathon the same year he started running.Now 63, he is running seven marathons in seven days on seven continents.He said taking it slow and stretching helped him get into running marathons.Dennis Beggs hated his first run. He was 55 years old and had been walking a lot to clear his mind while caring for his mom, who had Alzheimer's disease. He wanted to start running instead to "waste less time," he told Business Insider, so ran a quarter of a mile in spring 2017 and thought he'd never do it again.But the next week, Beggs, a farm owner from Wisconsin, decided to try again and began running incrementally longer distances each day. He didn't know exactly how far or long he was running because he never took a watch or a phone. So when his neighbor invited him to join a 10k race on Independence Day, he was surprised to come second. Beggs started running to clear his head while caring for his mother. Dennis Beggs At the race, a man encouraged him to run his first marathon. Looking back, his first marathon in October 2017 was a "disaster," but it motivated him to keep dedicating time to running.Now, at 63, he has completed many running challenges, including 10 marathons in 10 weeks. And on January 31, he started the World Marathon Challenge, which involves running seven marathons on seven continents in seven days, to raise money for the Alzheimer's Foundation of America.Beggs shared how he got so fit at 63 with BI.Beggs started with short runs"You start out small, and then you work your way up," Beggs said.He started out walking, and when he started running, he slowly increased the length of his runs. He was already fit from managing a farm, so he quite quickly was able to run for longer periods of time, while setting achievable milestones.Sohee Lee, a personal trainer, previously told BI that easing into working out by doing sessions a few times a week and not pushing yourself too hard is the most sustainable approach. Beggs in Johannesburg, where he completed a marathon. Dennis Beggs He appreciated the physical and mental benefits of runningBeggs said his lifestyle changed when he got fitter."You're going to see your body transform. You're going to lose weight, you're going to feel fitter, you're going to have much more energy. It'll lead to better nutrition, too, because it's like, 'Wow, I feel good. I don't really need a doughnut every day,'" he said.Plus, running is a great opportunity to clear his mind and think without distractions. Beggs might consider what he needs to do that day, pray, or mull over tough decisions."I always feel cleansed after I run. It relaxes me and gives me stability," he said. The runner's high is a feeling "like no other," he said, and has helped build his confidence.One 2024 study published in the journal Sports (Basel) found that people who ran regularly saw greater improvements in their mood after a run than those who ran occasionally. Beggs ran in the 2023 Tokyo Marathon. Dennis Beggs He does yoga and has massagesBeggs uses Thai massage to stretch out his muscles. Thai massage doesn't involve the kneading and rubbing associated with other forms of massage, but entails yoga-like poses and stretches with the assistance of a massage therapist, instead."It really helps with my stretching, and I feel like it means I have less chance to sustain injury because it's a more intense form of stretching," he said.A small 2024 study by researchers at Mae Fah Luang University, Thailand, found that participants with muscle fatigue recovered faster after 30 minutes of traditional Thai massage compared to participants who did one minute.He also does yoga in the winter when he's not doing as much physical farm work.What is known as active recovery, such as walking or gentle yoga, can improve blood flow, improve fitness performance, and soothe muscles.