Kate Middleton's Hiking: A Physiotherapist Says an Hour-Long Morning Walk Can Burn 300 to 500 Calories

Kate Middleton, the Princess of Wales, doesn't run marathons for the photographers. She hikes. In June she completed the National Three Peaks Challenge - climbing three summits in 24 hours - to raise money for the Royal Marsden Cancer Charity, which supports cancer treatment. Besides the mountains, she plays curling and tennis and rides a bike - but of all her sports, walking uphill is the one anyone can do.

She's not alone. Gwyneth Paltrow calls hiking active meditation, Jennifer Aniston uses it to clear her head, Jessica Biel says it keeps her fit without feeling like exercise, and Oprah Winfrey says that on the trail she sees her problems at their real size again. When so many people with personal trainers and home gyms choose an ordinary trail, it's worth asking what they get out there that they don't get in the gym.

Physiotherapist Francisco Gómez, from a Spanish wellness clinic, lists the benefits one by one. Heart and circulation: better blood flow, lower risk of heart disease and possible help with blood pressure. Energy: according to him, an hour-long morning walk on an empty stomach can burn 300 to 500 calories, depending on pace and intensity. Muscles: slopes work the legs, glutes, abdomen and back.

Then there's what the gym struggles to give you. Gentle movement can help the joints of people with osteoarthritis, time in nature can lower cortisol, the stress hormone, and walking lets you talk while you exercise - which makes it a sport even for people who hate running with all their heart. In a survey by a Spanish self-care association, hiking was the Spaniards' third-favourite physical activity, right after the gym and ordinary walking.

Trainer Patricia Ingelmo adds two more arguments: exposing more of your skin to the sun helps the body produce vitamin D, and hiking is cheap and can be done alone or with company. The membership fee is zero, and you set the timetable yourself.

The princess has private trails and security. We have Vodno above Skopje and mountains visible from almost every town in Macedonia. If the royal family's fitness "secret" is simply walking up a hill, why are so many of us still paying a monthly membership to walk on a treadmill that goes nowhere?