Passage 1
from “Exercise Builds Brawn—and Brains” by Esther Landhuis
1
Got an exam coming up? Head to the gym. It won’t just tone muscle and keep you fit. It could also rev up your
memory.
2
Plenty of research has shown that moving the body—whether jogging, lifting weights or even playing fitness
video games—helps the mind. However, many of those studies reported mental benefits only after participants
exercised regularly for months or years. Now there’s hope for couch potatoes: Just one 20-minute session of simple leg
exercises can give the brain a lift, a new study finds.
3
Its lead scientist, Audrey Duarte, works in the Memory and Aging Laboratory at the Georgia Institute of
Technology in Atlanta. As a neuroscientist, she’s interested in why memory starts slipping as people age. And she
suspected exercise might slow that decline. “We wanted to find simple things people can do to boost their memory,
even just a little bit,” she told Science News for Students.
4
Many earlier studies had asked volunteers to really move around. They assigned people to do various types of
aerobic exercise, such as walking for an hour three times a week. Aerobic exercise makes the heart and lungs work hard.
That helps to build muscle and improve blood flow. Duarte’s team set the bar far lower. They assigned participants to do
leg lifts—a type of resistance exercise. Such exercises rely on the contraction of muscles to build strength in particular
tissues. Leg lifts have a second benefit: ease. “Anyone can do a 20-minute bout of moving their legs up and down,”
Duarte says.
5
Indeed, these leg lifts would be easy enough for grannies to do — even patients with dementia. However, for
its initial study, Duarte’s group worked with college students. Recruiting them for research tends to be easier. The
researchers didn’t want gym rats or athletes, though. They wanted to see if a single session of leg lifts might benefit
even people who don’t exercise regularly.
6
Before, during and after the leg exercises, the researchers measured heart rate and blood pressure in each of
their 46 young recruits. They also took a small sample of saliva from each. From that they could measure an enzyme
called amylase. This enzyme helps to digest starch. It also increases during times of short-term stress—such as keeping
your hand submerged in cold water or getting filmed while giving an impromptu speech.
7
Research subjects in prior studies have faced those very stressors. The result? Increased stress hormones and
higher amylase levels—but better memory.
8
The leg lifts were performed using weights that targeted the quadricep muscles. The weight lifted was
adjusted to match each person’s maximal ability. Just 20 minutes of leg lifts produced amylase boosts similar to those
produced during short-term stress, Duarte’s team found. (Half the participants served as the control group. They moved
their legs up and down on the same machine. Here, though, a researcher lifted each person’s legs instead of relying on a
recruit’s muscles to do it.)
9
Before doing lifts, each recruit viewed a series of 90 pictures. Then they went home with the instruction to do
no more exercise. Two days later, they returned to the lab for a test. A researcher showed each person 180 photos—half
from the initial set—and then asked the subjects to indicate which ones looked familiar. The group that had done leg
lifts scored about 10 percent higher than the control group.
10
“What we found was on par with studies looking at how psychological stress can benefit memory in the short
term,” says Duarte. She thinks the magic happens during the “consolidation” phase. That takes place after learning. It’s
when memories are getting laid down in the brain.
11
Other scientists who study exercise and brain activities find the new results compelling. “Aerobic training has
taken center stage as the type of exercise for improving brain health,” says Teresa Liu-Ambrose. She’s a cognitive
scientist at the University of British Columbia in Vancouver, Canada. She notes, however, that “resistance training is
emerging as an equally good option . . . and you can reap the benefits quite quickly.”
Excerpt from “Exercise Builds Brawn—and Brains,” by Esther Landhuis, from Science News for Students.
October 2014.
Passage 2
Strong Body Helps the Mind by Stephen Ornes
12
A good workout doesn't just make the body stronger. It also produces a chemical that may keep depression
away, scientists report. Their findings come from a new study of mice and another in a small group of people. Doctors
have often prescribed exercise to help treat people with depression. The new data points to why that can work.
13
“This paper really emphasizes ‘strong body, strong mind,’” Andrew Miller told Science News. A psychiatrist at
Emory University in Atlanta, Ga., Miller did not work on the new study.
14
The researchers mapped out the protective activity of one chemical that the body makes during exercise.
These data may help explain why exercise can heal a person in different ways, Miller says. The study also may point to
new ways to treat brain disorders, he adds.
15
After a good workout, muscles produce a chemical called PGC-1 alpha 1. It signals the body to make more
blood vessels and more mitochondria (My-toh-KON-dree-ah). Those mitochondria are important features of cells. They
convert food into the energy that powers cells.
16
The new study shows that this ramp-up in PGC-1 alpha 1 has benefits that reach all the way to the brain. In
one set of tests, the scientists exposed mice to several things that cause stress. For instance, they cut back on how much
food the mice got to eat. They also exposed the animals to strobe lights and loud noises. After five weeks, the stressed
mice showed signs of depression. Their symptoms: They consumed less sweet water and did not try to swim when
placed in a tank of water.
17
The researchers then conducted the same tests on mice that had been genetically altered to produce high
levels of PGC-1 alpha 1. These mice did not show signs of depression after five weeks of stress. “Nothing happened,”
said Maria Lindskog, a neuroscientist at the Karolinska Institute in Stockholm, Sweden. The animals seemed unaffected,
she told Science News. It appeared, she concluded, that “the brain was completely protected.”
18
But her team didn’t stop there. They turned to a chemical called kynurenine (KY-nure-EN-een) that the body
produces during stress. When they injected this chemical into their mice, the animals showed signs of depression—such
as drinking less sweet water.
19
But the researchers found that PGC-1 alpha 1 helped transform kynurenine into a different chemical. That
new chemical had trouble reaching the brain. So mice whose muscles had produced high levels of PGC-1 alpha 1 no
longer became depressed. These animals seemed immune to the negative effects of kynurenine. The scientists found
that PGC-1 alpha 1 protected their brains from depression.
20
The new study shows that muscles can have a strong influence on other organs, Lindskog told Science News.
Muscle, she concludes, “is like a detoxifying organ.”
21
Her team looked for the same effects in people. After volunteers exercised for three weeks, their muscles
produced PGC-1 alpha 1 and other chemicals that helped lower kynurenine levels in the brain.
22
The study may point to better treatments for depression. Some people may benefit strongly from more
exercise, Miller says, or from drugs that stop toxic compounds from getting to the brain.
“Strong Body Helps the Mind,” by Stephen Ornes, from Science News for Students. October 2014.
Write an argumentative essay for a health magazine in which you take a position on whether or
not young people should exercise more. Your essay must be based upon ideas, concepts, and
information that can be determined through analysis of the two passages. Use evidence from
both passages to support your response.
Manage your time carefully so that you can
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
Plan your essay
Write your essay
Be sure to
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Include a claim
Address counterclaims
Use evidence from multiple sources
Avoid over relying on one source
Your written response should be in the form of a multi-paragraph essay.