Walking is a very good exercise-both in the morning and evening. It should be done in fresh air. Mild exercises, and 'yogasanas' affecting spine to keep it straight are also recommended.
Walking barefoot on earth and on grass wet with morning dew is beneficial. The earth sucks most of negativity through feet and clears Mooladhara 'chakra' . Sole 'chakra' is an extension of Mooladhara 'chakra' and is related directly to it. Sole chakra is also said to be related to heart 'chakra' .