What kind of exercise we should be doing and how many days/time a week at the age of 57 ?

Exercise: Your exercise routine depends on your physical health. Please see your doc to make sure you are healthy enough to exercise or if there are any exercises to avoid. Beyond that, consider at least 20 minutes of brisk movement 3 times a week for a minimum. It can be quick walking or light jogging. Better yet, speak w/a trainer at a gym and he/she can create a program for you. Peace & good health

Moderate activity: Exercises of moderate intensity are typically recommended. These activities will have you breathing harder and your heart beating faster. Examples include ballroom dancing, light bicycling (slower than 10 miles per hour), lawn mowing, moderate walking (3 to 4 miles per hour), gardening, and yoga. Exercise for at least thirty minutes five days per a week is typically recommended.