The U.S. Surgeon General told Americans last week that walking is one of the keys to health. An average of 22 minutes of daily moderate physical activity — roughly about 2.5 hours a week — could significantly reduce your risk of heart disease and diabetes, he said. Regular physical activity also can reduce symptoms of depression and mental illness. A fun way to start might be the 24th annual American Heart Association Heart & Stroke Walk 7 a.m. Saturday, Sept. 19 in Balboa Park. The event inspires participants to embrace a renewed commitment to heart-healthy living through walking and other healthful habits while hoping to raise more than $1 million to invest in research to discover new ways to treat and prevent cardiovascular disease and stroke. The non-competitive 4.1-mile route features teams of employees from local companies as well as community teams. Friends and family members of all ages are invited to join. Heart disease and stroke survivors will receive special survivor caps to distinguish them from the rest of the pack. There will also be a special one-mile course for survivors. Participants are invited to stick around for the expo afterward to sample Subway sandwiches, healthy snacks, entertainment and other wellness booths and activities, including free health screenings provided by UC San Diego Health. To register for the Heart Walk, visit sdheartwalk.org or call (858) 410-3849.