According to a new report, exercise is one of the best studied ways to protect thinking skills as you age.  The best studied ways to slow the decline:

Exercise.  Physical activity studies in middle age and older adults show that those who step up their exercise routines improve their scores on thinking tests.

Improve cardiovascular health.  People with healthy hearts and blood vessels tend to maintain healthier brains and are at lower risk for strokes, a major cause of cognitive impairment.  So control your blood pressure, cholesterol and weight, and don't smoke.

Watch out for medical conditions and medications that can impair thinking.  Conditions from diabetes to sleep apnea and medications such as some sedating antihistamines, sleeping pills and antidepressants have been linked with cognitive decline.