Cognition by numbers

Here’s some numbers for you.

In a study called Exercise for cognitive brain health in aging: A systematic review for an evaluation of dose, researchers performed what is called a meta-analysis of many studies on exercise and cognitive decline to see if they could determine a “dose” of exercise that is required to make a difference.  They found that the number was 52 hours over 6 months.  The subjects in the studies ranged from having normal cognition (59%) to mild cognitive impairment (26%) to dementia (15%) and were assessed for “improvement in cognitive performance.”  Since this was a compilation of many studies, one caveat is that each study may have measured cognitive performance differently.  So something on the order  of 2 hours per week is what it seems to take to make a difference.  This is basically in line with recommendations from the U.S. Office of Disease Prevention and Health Promotion which recommends 75-150 minutes of vigorous or moderate intensity exercise per week for general health.

Here’s another couple of numbers on sleep and cognition:  5 and 10.  In a study called Association Between Daily Sleep Duration and Risk of Dementia and Mortality in a Japanese Community, researchers followed 1500 Japanese subjects older than 60 for 10 years while surveying them on sleep duration.  They fond the highest rates of dementia or death in those that slept either less than 5 hours per night or more than 10 hours per night.  There was also an increased risk of dementia in those taking sleeping medications.

There you go.  52, 5 and 10.  To boil it down, exercise about 2 hours per week and if you’re sleeping less than 5 or more than 10 hours per night, talk to your doctor about it.  Maybe it’s just the way you are, but worth looking for an issue like obstructive sleep apnea or other nighttime issue that can interfere with sleep.

-DS (11-5-18)