Turning 30 is a big milestone for a lot of people, one of those markers of our transition from capricious youth into responsible adult. I just celebrated my 30th birthday, and I think every single one of my friends made some comment along the lines of, “You must feel really old now!” Well I have to say, I don’t really feel that old, though I’m not entirely sure what being old is supposed to feel like. Maybe I’m not as strong or fast as I was back in high school when I was lifting weights and playing sports everyday, but I think that’s more a consequence of a lack of exercise over the last few years, rather than an effect of aging. And I probably lose my keys more often now than I did when I was younger, but I think that’s probably because I have a lot more places to lose them than I did when my life was confined to a dorm room or studio apartment.
Of course, as a wannabe scientist, I know that a question like “Is 30 old?” can’t be answered with a few anecdotes and personal intuitions. First, we need to clearly specify what we mean by “old.” In this context, old is definitely not being used as a compliment; in that case, I think most people probably associate the pejorative connotations of old with the kinds of physical and cognitive declines that are associated with normal aging (more on that later). So our question can be refined a bit - we can ask, “Do 30-year-olds suffer from the same kinds of physical and cognitive ailments as older adults?”
Lets look at the physical side first. We know from many studies that there are age-related declines in physical attributes like muscle strength, balance, coordination, etc., such that older people tend to have less strength, worse balance, and poorer hand-eye coordination than younger people. But as it turns out, these declines don’t really kick in until people are in their mid- to late-30s, and sometimes not until people are in their 50s. According to one study, some of these declines affect men before they affect women, which doesn’t bode well for me, but probably makes my wife pretty happy.
We get a similar picture of aging from the cognitive side. Though some of our perceptual faculties, like seeing and hearing, start to gradually wear out in our mid-20s, most research on broader cognitive attributes like intelligence suggests that we’re in just as good of shape at 30 as we are in our early 20s. One well-known study showed that adults tend to hit their “peak” intelligence by around age 26, but that 30-year-olds are generally more intelligent than people in their late teens and early 20s (take that, you whippersnappers!). This isn’t a totally cut and dry question, however. Scientists are still arguing about the correct way to measure cognitive decline across the lifespan. The jury may be still be out, but for the time being, it seems safe to conclude that my mind is no worse for the wear at 30.
So, to everyone who called me old on my birthday - well, first of all, thanks for thinking about me; but second, it doesn’t look like you’ve got science on your side in this one. We get older every moment of every day, but we don’t really start to show any significant effects of aging at 30. Now, if you’ll excuse me, I have some decaf tea to drink before Matlock starts, and I have to make sure I get to bed at a reasonable hour if I want to beat all the other walkers to the mall.