At the beginning of 2010 I sent this email to my mom:
Mom,
I still don’t know if you’re receiving emails from me, but I will keep sending them just the same…
From the New York Times:
In a 2006 study of people aged 60 to 79, those who were assigned to walk briskly three days a week for 45 minutes a day experienced an increase in the brain’s volume, especially in regions involved in memory, planning and multitasking.