Just one hour a week of brisk walking may stave off disability in older adults with arthritis pain, aching or stiffness in a knee, hip, ankle or foot, according to a study unveiled on Monday.
"This is less than 10 minutes a day for people to maintain their independence. It's very doable," said," said Dorothy Dunlop, a professor at Northwestern University in the US.
"This minimum threshold may motivate inactive older adults to begin their path towards a physically active lifestyle with the wide range of health benefits promoted by physical activity," said Dunlop, lead author of the study published in the American Journal of Preventive Medicine.
About two in five people with osteoarthritis -- most of whom have it in their lower joints -- develop disability limitations, researchers said.
The study found an hour of weekly moderate-to-vigorous physical activity allowed older adults to maintain their ability to perform daily tasks like getting dressed or cross a street before a traffic light walk signal changed.
The weekly hour of exercise reduced their risk of mobility disability by 85 per cent and their risk of activities of daily living disability by almost 45 per cent.
Four years after the start of the study, 24 per cent of adults who did not get the weekly hour of brisk physical activity were walking too slowly to safely cross the street, and 23 per cent reported problems performing their morning routine.
The researchers analysed four years of data from more than 1,500 adults in the national Osteoarthritis Initiative from Baltimore, Pittsburgh, Columbus and Pawtucket, Rhode Island.
All the adults had pain, aching or stiffness in lower extremity joints from osteoarthritis but were free of disability when they began the study. Their physical activity was monitored using accelerometers.
"Our goal was to see what kind of activity would help people remain free of disability," Dunlop said.
Guidelines in the US recommend older adults with arthritis should participate in low-impact activity.
For substantial health benefits including reducing the risk for heart disease and many other chronic diseases, these guidelines recommend older adults participate in at least 2.5 hours a week of moderate-intensity activity.
However, that level of activity can be daunting for inactive older adults with lower extremity pain, Dunlop said.
"We hope this new public health finding will motivate an intermediate physical activity goal. One hour a week is a stepping stone for people who are currently inactive. People can start to work towards that," Dunlop said.