Even if you're a runner or swimmer, hiking can work a different set of muscles that involve climbing and balance. You'll feel it.

In addition to the workout you'll get from hiking, local trails stimulate the senses with the sights, smells and sounds of nature. Whether the journey takes you through a bamboo grove, past Norfolk pines or overlooking sweeping vistas of Oahu that you would never see from sea level, hiking offers a temporary escape from urban life.

Lost in the midst of birdsong and the occasional waterfall, you just might forget how many calories you've been burning along the way.

Oahu offers more than 80 trails ideal for a day hike with a wide option of terrains — valley hikes and ridge hikes — that can give you varying workouts.

Try carrying a backpack and hiking Waiau, a 12-mile ridge trail to the Koolau summit with plenty of ups and downs that will give your legs the ultimate workout while offering you some stunning views along the way.

For a good, upward climb, you can try cardiac hill at Waimano Falls, the ascent to Mount Olympus (Waahila Ridge) or the switchbacks at Kealia near Dillingham Airfield on the North Shore.

If it's hiking outdoors that you enjoy, without the specific focus on fitness, there are plenty of other options. A leisurely hike will still give you a workout, and can burn several hundred calories even at a moderate pace.

If you want to explore various trails throughout the island of Oahu, check out the Hawaiian Trail & Mountain Club, which is getting ready to celebrate its 100th anniversary in April. HTM organizes hikes every weekend, ranging from novice, 3-mile hikes along gentle slopes to intermediate 12-mile up-and-down scrambles along narrow ridges.

On New Year's Day it's HTM's tradition to hike up the makai side of Koko Crater (including a scramble over a narrow rock arch) and then down the tram tracks, which offers a different point of view. Nonmembers are asked for a $3 donation. For more information on club membership and a schedule of hikes, go to http://www.htmclub.org.

The Sierra Club also organizes weekend hikes on Oahu, Maui, Kauai and the Big Island, but requires participants to stay together. A $3 donation is requested for nonmembers, $1 for members. Go to www.sierraclubhawaii.com for more information.

CALENDAR

» Kaunala: Six miles, intermediate ridge, with the Hawaiian Trail & Mountain Club. Drive to the North Shore for this pleasant woodsy stroll on Saturday. Coordinators: Dayle and Jacque Turner. Donation: $3 for nonmembers 18 and older. Visit htmclub.org.

» Waimea Valley Hike Series: Weekly Saturday hikes begin promptly at 9 a.m. Register at 8:30 a.m. at the Waimea Valley Visitor Center. Children 15 and younger must be accompanied by an adult. Admission fee extra. Reservations required. Call 638-7766. Family hikes, including children at least 7 years old, also offered. A strenuous hike is offered the last Saturday of the month for ages 12 and older, with a five-person minimum and at a cost of $15 per person.

» South Ridge Lookout: Two-mile, moderate trek up South Ridge takes you above the waterfall for beautiful views looking down into Waimea Valley, Saturday. Duration is three hours; for ages 12 and older. Fee: $5.

» Palehua-Palikea at Makakilo: Four miles, easy ridge hike with the Sierra Club on Sunday. Not for those uneasy about heights. This hike offers views of native plants, scenic panoramas and tree snails. Reservations and completed waiver forms required. Visit www.hi.sierraclub.org/oahu/outingsched.htm.