(Yosemite National Park)
Distance: 5-mile loop
At Yosemite, the shallow Mirror Lake is fed by melting mountain snow. When the water is calm, it lives up to its name, reflecting Half Dome (a colossal rock formation hovering 5,000 feet above) and Mount Watkins rising in the distance. A shuttle will bus you to the trailhead, paved for the first mile until you reach the unpaved loop along the rushing water of Tenaya Creek—a nice spot for a snack and a drink. Visit late spring to early summer; by late July, the lake dries up.
Related: Healthier Meals at 5 National Parks
Distance: 5 miles
One of the Smokies' most popular hikes, the trail follows a creek through dense pine and oak forest, where whitetail deer, elk and fox frolic. About 2½ miles in you'll reach Abrams Falls—a roaring 20-foot waterfall (strong currents make swimming dangerous; don't do it). An open area near the falls is a fine spot to lounge and lunch.
(Acadia National Park)
Distance: 4.5 miles
Tourists visit Apostle Islands for the famous sandstone sea caves carved by centuries of wave action on Lake Superior. A paved boardwalk for the first mile, this super-accessible trail allows you to find your own rhythm. From there, a dirt path meanders over the caves. Two miles in is the first lookout point to the artfully carved, red-orange sea caves.
Distance: 4.4 miles
The majestic combination of ocean, mountains and wildlife makes Acadia a top-visited park. This out-and-back trail rambles along the Mount Desert Island shore and provides many places to rest and test. Two must-sees: Thunder Hole, an inlet named for crashing waves; and Otter Cliff, where pink granite juts out 110 feet above sea level. Extend your step count on short side trails along the way.
(Grand Canyon National Park)
Distance: up to 13 miles
Take in miles of Grand Canyon views on the easy South Rim trail. Scenic overlooks such as Hopi Point (great sunset views) and Yavapai Point (glass observation area) offer awe-inspiring resting retreats for photos and blood glucose checks. Simply pick a starting point with the shuttle service.
Find more national park hikes at nps.gov. Look for trails rated easy or moderate.
Keep blood sugar in check during a hike with these diabetes essentials:
Water: Drink 12–24 ounces per hour.
Snacks: Choose good sources of carbohydrate: granola bars, trail mix, fresh fruit. Sports drinks offer carbs, electrolytes and hydration. A rule of thumb is 30–60 grams of carb per hour, but talk with your health care provider for specifics.
Fast-acting carb source: Think glucose tablets, glucose gel or fruit juice.
Monitoring supplies: Bring extra. You'll need to check your blood sugar more often and should have backups in case of emergency (batteries for devices, too).
Any prescribed medications or insulin
Wear synthetic fiber socks to wick moisture from your feet.
Source: Don Kain, M.A., RD, LD, CDE, diabetes program education and outreach manager at Oregon Health & Science University in Portland.