Well, as I drift, one year at a time, further into the danger zone I can't say I've noticed any cognitive decline - but then again I don't suppose I
would. It's usually others that see we've gone from
The one thing I have noticed though is that aerobic exercise gets harder and harder as the years go by and you need to have some very strong underlying motivational reason to keep at it. Almost all of the reasons that worked when you were 20 (playing competitive sport, attract opposite sex etc) are pretty much irrelevant by 60 for many people and you have the additional worry that stressing your body during an aerobic workout might precipitate some catastrophic event.
Many people of mature years might weigh up the advantages of "modest improvements in attention and processing speed, executive function, and memory" to be gained by going out exercising on a cold, wet, winter's night and decide that they'll take advantages offered by a
and a curry instead.