At age 13, chess prodigy Magnus Carlsen became the third-youngest grandmaster in history. He didn't stop there. Carlsen won his first World Chess Championship in 2013 and has every year since. Later this month, the 25-year-old will again defend his world title.

To maintain this level of chess superstardom, one might assume Carlsen spends every waking minute behind the chessboard or running through gaming strategies in his head. But Carlsen attributes a second type of training as equally important to his success: staying in peak physical shape. He plays on a recreational soccer team in his hometown and practices yoga. The Norway-born chess champion told The Wall Street Journal that maintaining a healthy diet and staying active are crucial for optimal performance, the same way they are for other athletes.

When one chess match can take five hours, physical and mental stamina work hand in hand. Carlsen's time on the soccer field and on the yoga mat help him perform his best when he sits down to compete. The Wall Street Journal examined his training regimen and offered insight into why the chess master believes the soccer field and yoga studio are key to strengthening his chess game.

Build endurance

"No sport challenges your endurance like soccer, both mentally and physically," Carlsen says. Over a 90-minute game, a soccer player can run upwards of seven miles. With the coordination challenges mixed in from dribbling and passing the ball, researchers who study kinesiology report soccer as one of the best activities to activate brain blood vessels and increase blood flow to the brain.

Improve sleep

Sleeping poorly can be detrimental to any athlete, especially one whose matches can last for hours. A healthy regimen of physical exercise naturally helps to improve sleep. Keeping his body in peak physical shape helps Carlsen sleep better so he's refreshed and focused for his chess games. "Games are lost or won in the final hours due to mistakes caused by fatigue," he says.

Relieve tension between competitions

Many prodigies dedicate every spare minute to the sole activity in which they excel. Carlsen finds it's also important to carve out time for fun non-chess activities to relieve tension. Soccer isn't a doctor-prescribed activity. He genuinely enjoys playing, because he's competitive by nature. This helps to take the edge off when Carlsen sits down to compete, making him less likely to choke under the pressure.

Calm the mind

Though soccer is Carlsen's preferred off-the-board activity, he also incorporates yoga into his routine to help him settle his mind between matches. A calmer mind helps him better focus on game strategies. It's also easier to practice yoga than play soccer when he travels to compete. When he's on the road, Carlsen will look for hot yoga studios and pop into classes.

Physical fitness and brain health are unmistakably connected. Cardio exercise has recently been found to ward off depression, and a new study found that weightlifting could prevent cognitive decline and the development of dementia in older adults. Even if you have no plans (or the talent) to become a grandmaster chess champion, your brain and body will benefit from staying physically active. It doesn't have to be soccer or yoga, either. If you can find something you like doing that gets your heart rate up, increases blood flow to the brain, and encourages concentration, go for it. Your attention and focus will thank you.

To learn more about Magnus Carlsen's mental and physical training routine, read the full Wall Street Journal article.