Fastpacking the JMT isn't just for the lunatic fringe: Summer conditions make it a perfect place for any hiker to go light. That said, our group found seven days pretty brutal. More reasonable? Take 10. Fit backpackers who avoid the worst afternoon heat and keep their packs under 25 pounds can average 22 miles a day without killing themselves. Here's how.
Hike north to south to adjust gradually to the highest elevations.
Start early every day. Hike in the cool morning and evening hours, and rest during the afternoon heat.
Plan fewer miles on days when your pack is heaviest, and more miles when you're traveling light.
Hiking southbound, the hardest climbs are to Mather Pass, Glen Pass, Forester Pass, and Trail Crest/Mt. Whitney. If possible, avoid these in the afternoon.
From Yosemite Valley, carry only hydration packs for the 22 miles to Tuolumne. Have your backpacking gear and food waiting. Eat a big meal in the Tuolumne café.
At Red's Meadow (800-292-7758 or 760-934-2345, redsmeadow.com/the-resort), resupply for the next 50 miles by mailing or delivering packages in advance (for a fee). Or have a buddy meet you. Eat at the Mule House Café.
Resupply a final time at Muir Trail Ranch (209-966-3195, muirtrailranch.com/resupply), about a mile off the JMT near the path's midpoint. Ship non-perishable food in advance; a fee is charged.
Eating and Drinking
Go liquid light. Water is plentiful along the JMT, so carry only 1 to 1.5 liters (2-3 lbs.). Bring energy drinks to keep your body primed with electrolytes.
Don't overpack food. You won't eat more than 4,000 calories a day. Weigh your food and keep it to 2 lbs./day–or less.
Really slash weight. Ditch the stove and fuel in favor of dry foods: peanut butter, tortillas, cheese, pepperoni, dried fruits, nuts, sesame sticks, and peanut M&Ms. You'll appreciate the convenience when you're tired.
The JMT has 40,000-plus feet of uphill and 36,000 feet of down. You can't do it off the couch.
Establish a program. At least three months prior, begin a four-week cycle, building up from a "rest" week of 3-4 light workouts to a "peak" week of 5-7 hard workouts. Plan a rest week to fall right before your hike.
Wear a pack. Carry 10-20 lbs. on training hikes, stairs, or machines, or 5-6 lbs. for running.
Cross-train. Do 2-3 hours per week of core exercises, yoga/stretching, and weight training.
Hit the trail. Schedule two or more steep dayhikes a month; push your pace. Build up to a shakedown overnight hike with consecutive 25-mile days carrying your thru-hiking gear and food.
Train your mind. Break down big-mileage days into pieces that seem less daunting–how far you'll go by mid-morning, by your afternoon rest, by dinner, by camp.