Women hiking
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There are many reasons we should be getting outside more often: Researchers have found that spending time in local and national parks can help us cope with stress and recover from illness and injury. It can even provide a morale boost. (A small British study in 2007 found that people who strolled through a park reported an increase in self-esteem, compared to those who were sent to a shopping mall—they actually felt worse about themselves.)

Because hiking isn't quite as simple as putting one foot in front of the other, we asked Mandy Pohja, a wilderness instructor with the National Outdoor Leadership School (NOLS), to give us the top mistakes that tend to trip people up.

1. They choose the wrong path.

Pohja sees this time and again. Not only do newbies wander onto trails that are too tough, but people looking for an intense workout accidentally choose an easy amble, get bored and go back to the treadmill at the gym. Hiking trails are usually ranked by difficulty on a scale of 1 to 5, with 1 and 2 presenting low risks of real danger. "In the third class, you might have to use your hands here and there to balance or scramble," says Pohja. "In the fourth class, you're using both hands to pull yourself up, and class 5 is basically rock climbing"—definitely not for beginners. Keep in mind, for a rough guide to your level of effort, you should add about two additional energy miles per every 1,000 feet of elevation gain. So if you're hiking one mile uphill on a mountain taller than 1,000 feet, it will feel like three miles.