Hiking at high altitudes pushes the heart to work harder to pump blood more efficiently due to the decreased oxygen levels.

Start with a moisture-wicking base layer to keep sweat in check. Next, add a lightweight fleece or wool for insulation, and top it off with a waterproof, breathable outer layer. Shailene regularly ...

The Darn Tough Light Hiker Micro Crew is another great lightweight option. We like the thin cushioned footbed and seamless ...