Why do we age? –Logan, 12, Pullman, Wash.
Dear Logan,
It’s usually later in life that we see the more dramatic signs of aging, like gray hair, wrinkles, and lots of birthday candles on our cake. But we really start growing older from the time we are born.
The way humans change across the lifespan fascinates my friend Cory Bolkan, an associate professor of human development here at Washington State University.
“There isn’t really one factor, one theory, or one line of research that can explain aging,” Bolkan said. “It’s kind of an exciting area with lots of opportunities to explore.”
For example, some scientists are really curious about how people age in space versus here on Earth.
NASA astronaut Scott Kelly recently returned from a year-long mission aboard the International Space Station. Scientists are curious if conditions of space, like living in weak gravity or being around particular particles from outside the solar system, might change the way a person ages.
They are also interested in the things we can’t always see right away.
Scientists think part of the answer to your question may lie in our genes. So, they want to look at Scott’s DNA.
“Our genes contain information about us that’s been passed down from our parents, grandparents and ancestors,” Bolkan said. They hold the instructions for hair color and skin color, for example.
Scientists are particularly interested in studying Scott because he also has an identical twin brother. That means they were born with DNA that is exactly the same. Scientists will zoom into the ends of their DNA and observe sections that we think might be linked to growing older.
But it’s not just our genes that play a part in why we age, Bolkan said.
“You can have two identical twins who share the exact same DNA,” Bolkan said. “You can look at them again decades later and you’ll see that genetically they are more different.”
She said this makes the answer to your question even more complex. Our environments interact with our genes, too.
There are certain things in our environment that can damage our genes. The damage can be a result of activities like smoking or not wearing sunscreen. This kind of activity can speed-up the aging process, Bolkan said. Our physical appearance changes as a result of “wear and tear” on our DNA.
While we haven’t pinpointed the exact answer to why we age, we are finding clearer answers to other questions about growing older.
For example, the power of our mind can change the way we age, Bolkan said. Studies have shown people with a positive outlook on aging actually tend to live longer.
“People say ‘I don’t want to get older, it doesn’t look like fun’,” Bolkan said. “But when you look at the research and you look at happiness, we are the happiest later in life.”
Perhaps some of your best birthdays will be the ones with the most candles on your cake.
Sincerely,
Dr. Universe
Why do we get brain freezes? –Hannah, 9, Monroe Elementary
Dear Hannah,
You’re enjoying some ice cream, when suddenly you feel a pain in your head that hurts a whole lot. It’s like it came out of nowhere, and in a matter of seconds, it’s gone.
These instant headaches, or brain freezes, often strike when we eat or drink something cold. And like you, some scientists are curious about why brain freezes happen. So they’re testing out some different ideas.
That’s what I found out from my friend Bill Griesar, a brain scientist at Washington State University.
One theory is that when you eat or drink something cold, it triggers a change in the blood vessels lining your mouth and throat.
Blood vessels are like little tubes carrying blood to the brain. A change in temperature can make these blood vessels grow wider.
“So you get this super painful rise and intense headache-y kind of feeling,” Griesar said. “The nice thing about ice cream headaches, is, very quickly, the vessels constrict. They go back to their normal size.”
As you experience a change in your blood vessels, it may set off other events in your brain and body.
Griesar said brain freezes might be connected to an important nerve in your face. Our nerves help us move, think, and feel in all kinds of ways.
It just so happens Griesar and his students are learning about one nerve that helps the brain and face communicate: the trigeminal nerve.
The nerve stretches out across your face in three branches.
“One goes to a part of your mouth, one goes below your mouth, one goes around your eyes,” Griesar said.
Along these branches there are clumps of neurons called ganglia that help carry information from your face to your central nervous system.
Nerves and ganglia can help different parts of your head and body communicate. Because it stretches across your face, the trigeminal nerve might be why you can feel an ice cream headache in your eyes or nose, too.
The narrowing and widening blood vessels appear to put a lot of pressure on ganglia near the trigeminal nerve. The trigeminal nerve sends a message to the brain that you are in pain.
It may feel like the brain freeze is inside the brain, but it’s likely being experienced as pain in the face, and the meninges, which are layers of tissue, with pain-sensing neurons, surrounding the brain.
Nerves often communicate pain to warn us of something dangerous. But the pain from brain freezes doesn’t appear to be harmful.
We’ve still got more investigating to do when it comes to why exactly we get brain freezes. I think I’ll go do an experiment of my own at Ferdinand’s Ice Cream Shoppe. Here at Washington State University, they make my favorite ice cream. I’ll have to eat a bunch of it—in the name of research of course.
Sincerely,
Dr. Universe
Got a science question? E-mail Dr. Wendy Sue Universe at Dr.Universe@wsu.edu.. Ask Dr. Universe is a science-education project from Washington State University.
