Passage 1
from “Exerci
se Builds Bra
wn—
and Brains”
by Esther Land
huis
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Got an exam coming up? Head to the gym. It won’t just tone muscle a
nd keep you fit. It could also rev up your memory.
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 mo
nths or years. Now there’s hope for couch potatoes: Just one 20minute session of simple leg exercises
can give the brain a lift, a new study finds.
Its lead scientist, Audrey Duarte, works in the Memory and Aging Lab
oratory at the
Georgia Institute of Technology in Atlanta. As a neuroscientist, she’s inte
rested in why
memory starts slipping as people age. And she suspected exercise might s
low that
decline. “We wanted to find simple things people can do to boost their m
emory, even just a little bit,” she told Science News for Students.
Many earlier studies had asked volunteers to really move around. The
y assigned
people to do various types of aerobic exercise, such as walking for an hou
r three times a
week. Aerobic exercise makes the heart and lungs work hard. That helps t
o build muscle
and improve blood flow. Duarte’s team set the bar far lower. They assign
ed 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 ben
efit: ease. “Anyone can do a 20minute bout of moving their legs up and down,” Duarte says.
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 coll
ege students.
Recruiting them for research tends to be easier. The researchers didn’t wa
nt 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.
Before, during and after the leg exercises, the researchers measured he
art rate and
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blood pressure in each of their 46 young recruits. They also took a small s
ample 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 shortterm stress—such as keeping your
hand submerged in cold water or getting filmed while giving an impromp
tu speech.
Research subjects in prior studies have faced those very stressors. The
result? Increased stress hormones and higher amylase levels—
but better memory.
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 2
0 minutes of leg
lifts produced amylase boosts similar to those produced during shortterm stress, Duarte’s
team found. (Half the participants served as the control group. They mov
ed their legs up
and down on the same machine. Here, though, a researcher lifted each per
son’s legs instead of relying on a recruit’s muscles to do it.)
Before doing lifts, each recruit viewed a series of 90 pictures. Then th
ey 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.
“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 hap
pens during the
“consolidation” phase. That takes place after learning. It’s when memorie
s are getting laid down in the brain.
Other scientists who study exercise and brain activities find the new re
sults
compelling. “Aerobic training has taken center stage as the type of exerci
se for improving brain health,” says Teresa LiuAmbrose. She’s a cognitive scientist at the University of
British Columbia in Vancouver, Canada. She notes, however, that “resist
ance training is
emerging as an equally good option . . . and you can reap the benefits quit
e 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
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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 prescrib
ed exercise to
help treat people with depression. The new data points to why that can w
ork.
“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.
The researchers mapped out the protective activity of one chemical tha
t the body
makes during exercise. These data may help explain why exercise can he
al a person indifferent ways, Miller says. The study also may point to ne
w ways to treat brain disorders, he adds.
After a good workout, muscles produce a chemical called PGC1 alpha 1. It signals the
body to make more blood vessels and more mitochondria (My-toh-KONdree-ah). Those
mitochondria are important features of cells. They convert food into the e
nergy that powers cells.
The new study shows that this ramp-up in PGC1 alpha 1 has benefits that reach all
the way to the brain. In one set of tests, the scientists exposed mice to sev
eral things that
cause stress. For instance, they cut back on how much food the mice got t
o eat. They also
exposed the animals to strobe lights and loud noises. After five weeks, th
e 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.
The researchers then conducted the same tests on mice that had been g
enetically altered to produce high levels of PGC1 alpha 1. These mice did not show signs of
depression after five weeks of stress. “Nothing happened,” said Maria Li
ndskog, a
neuroscientist at the Karolinska Institute in Stockholm, Sweden. The ani
mals seemed
unaffected, she told Science News. It appeared, she concluded, that “the b
rain was completely protected.”
But her team didn’t stop there. They turned to a chemical called kynur
enine (KY-nure-ENeen) that the body produces during stress. When they injected this chemic
al into their mice, the animals showed signs of depression—
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such as drinking less sweet water.
But the researchers found that PGC1 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 PGC1 alpha 1 no longer became depressed. These
animals seemed immune to the negative effects of kynurenine. The scient
ists found thatPGC-1 alpha 1 protected their brains from depression.
The new study shows that muscles can have a strong influence on othe
r organs,
Lindskog told Science News. Muscle, she concludes, “is like a detoxifyin
g organ.”
Her team looked for the same effects in people. After volunteers exerc
ised for three weeks, their muscles produced PGC1 alpha 1 and other chemicals that helped lower
kynurenine levels in the brain.
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 co
mpounds from getting to the brain.
“Strong Body Helps the Mind,” by Stephen Ornes, from Science News for Students. Oct
ober 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


Plan your essay
Write your essay
Be sure to



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 multiparagraph essay. Spend about 90minutes on this essay, incl
uding the time you spend reading the passage(s), planning,
and writing your essay.
Type your answer in the space provided.