Tens of millions of Koreans now track their daily steps through reward apps such as Cashwalk, Toss, and Samsung Health, making 10,000 steps a day a staple of personal health management. But experts warn that treating walking as the sum total of health care could backfire, particularly for those over 50.
Walking does not build muscle, according to the medical community on Wednesday. Aerobic exercise burns calories but has no direct link to muscle synthesis. As muscle mass declines, joints absorb the full force of impact, triggering a cascade of deterioration — osteoporosis in one's 60s, pelvic deformation in the 70s, and falls in the 80s.
Hong Jung-ki, a sports medicine specialist, appeared recently on "Slow Aging," a YouTube channel run by Jung Hee-won, a professor of geriatric medicine at Asan Medical Center. "People mistakenly believe walking alone will improve their health, but if you only burn energy without synthesizing muscle, you lose muscle," Hong said. "The ankles and knees lose their capacity to absorb impact, which is why so many people run once and then cannot run again for five months."
Citing U.S. research showing that a significant share of hip fracture patients over 70 die within a year, Hong stressed that building muscle from a young age is directly tied to survival in old age.
After age 50, the focus of exercise must shift. "Too many patients who come to my clinic say, 'I exercise — I walk 10,000 steps a day,'" Hong said. "They need to quickly abandon the illusion that walking 10,000 steps will build muscle."
Jung agreed. "If you go to Olympic Park, you still see many people walking diligently, but walking alone cannot prevent sarcopenia," she said. Strength training should come before aerobic exercise. Muscle should be built from the bottom up — starting with the calves, then the hamstrings, thighs, glutes, and erector spinae — by making simple daily movements such as heel raises and half squats into habits.
Arthritis is no exception. "It is a misconception that people with bad joints should only walk," Hong said. "Even light bodyweight movement can reduce pain, and you can gradually increase intensity by 20 to 30 percent while keeping range of motion limited."
He also noted that descending stairs engages 30 percent more muscle than climbing them. Muscle soreness that disappears within two days after exercise is a sign of growth, but if it lasts more than three days and is accompanied by swelling, intensity should be reduced immediately.
Speed and impatience are also warning signs. "Chasing visible results too quickly is the trap of the Korean style of exercise," Hong said. "If you have neglected your body for the 20 years since age 35, you need to build mobility slowly and conservatively."
The recent running boom is welcome, but suddenly ramping up intensity by comparing one's pace with others is a shortcut to injury. Adding a single set of squats to the time spent walking 10,000 steps can reshape the health trajectory of those in their 50s and beyond.
