Just two weeks ago I made the plunge and decided to join one of my most fearless friends on another high-altitude excursion across the world: Aconcagua in Argentina. At 22,841 ft., this mountain will be the highest (and hardest) summit we’ve ever pursued, and I couldn’t be happier to be embarking on this expedition with one of my bravest, most driven and adventurous friends.

When I tell people I’m leaving in a week to climb the tallest mountain outside of the Himalayas, the highest point in the Western hemisphere, and the Seventh Summit of South America – the first question I get is inevitably: How are you training for high altitude while you’re here at sea level?

The easiest (and only) answer: You simply can’t prepare for altitude. But you can condition your muscles and mind to be ready once you arrive.

Here are the main ways I’ve been amping up my cardio, strength, and endurance training for Aconcagua the last three weeks…

(1) Trail Running

Despite its notorious rain, Portland is one of the top destinations for runners in the country, partly due to the trails it has right within its city blocks.

Hands down, my new favorite running trail has been Leif Erikson Drive. Super accessible from anywhere in NW Portland as well as right off of the freeway, this wide, gradual, and feet-friendly trail is over 11 miles long. Plus: this route features distance markers every 1/4 mile, which make it super easy to track your progress. I started out at 10 miles, then onto 12, and on my latest trip I reached 15 miles round-trip. It’s definitely my go-to spot for upping my mileage week after week as my climb approaches.

This has been my first winter back in Oregon since high school, and the adjustment from a California climate to the snowy season we’ve been having has been a learning lesson for my layering system. I’d read some time ago that cold air makes your lungs work harder to metabolize oxygen, so frigid temperatures should get you used to these same effects at high-altitude and help enhance your ability to acclimatize. So in a way, the winter weather is really doing me a favor.

(2) Strength Training

Because I already love running, the first to-do of my training list was a cinch. I knew that my biggest challenges would come in strength training, which I hadn’t done since before I left on my worldwide trip in February (nearly a year ago). So I got to dust off my weights, and I now dedicate 3-5 days per week on different arm, abdominal, and leg muscles during 20-40 minute HIIT (high intensity interval training) sessions.

My strength training regimen also includes weighted walking, which is when the photo above was taken. On this brisk Friday afternoon I loaded my backpack up with 40 lbs of Nalgene water bottles, handheld weights, and heavy books to hike out of Lower MacLeay Park. I was not paying attention to how far I could go; I knew that distance and pace mattered little to me today. I simply set out with a goal of spending at least 2.5 hours without dropping my pack, continually moving, to get my entire body used to the strain that would be put on it on the slopes of Aconcagua.

At altitude, every little detail is over-exaggerated. Weight feels heavier, breathing feels harder, muscles are more sore and headaches are more severe. The more I can get my body used to this agony  while stuck in the city, the better I’ll perform in the mountains.

(3) Duration Over Distance

Throughout all of my training, no matter where, when, or what; my main focus has been on endurance. Endurance Athletics is all about how long you can last under extreme physical strain – and that all comes to how well you are prepared for it.

That’s why when you’re training to do a seriously intense athletic feat, it’s important to place a huge emphasis on duration over distance. Even if you find yourself trotting downhill and hiking slowly uphill (as I did on the day that this photo was taken), the most important part of training is to work through the hurt. And trust me, your training should hurt. After all…

Progress doesn’t happen within your comfort zone.