LIFT WEIGHTS IMPROVE YOUR MEMORY
Here's another reason why it's a good idea to
hit the gym: it can improve memory. A new Georgia Institute of Technology study
shows that an intense workout of as little as 20 minutes can enhance episodic
memory, also known as long-term memory for previous events, by about 10 percent
in healthy young adults.
The Georgia Tech
research isn't the first to find that exercise can improve memory. But the
study, which was just published in the journal Acta
Psychologica, took a few new approaches. While many existing
studies have demonstrated that months of aerobic exercises such as running can
improve memory, the current study had participants lift weights just once two
days before testing them. The Georgia Tech researchers also had participants
study events just before the exercise rather than after workout. They did this
because of extensive animal research suggesting that the period after learning
(or consolidation) is when the arousal or stress caused by exercise is most
likely to benefit memory.
The study began with
everyone looking at a series of 90 photos on a computer screen. The images were
evenly split between positive (i.e. kids on a waterslide), negative (mutilated
bodies) and neutral (clocks) pictures. Participants weren't asked to try and
remember the photos. Everyone then sat at a leg extension resistance exercise
machine. Half of them extended and contracted each leg at their personal
maximum effort 50 times. The control group simply sat in the chair and allowed
the machine and the experimenter to move their legs. Throughout the process,
each participant's blood pressure and heart rate were monitored. Every person
also contributed saliva samples so the team could detect levels of
neurotransmitter markers linked to stress.
The participants
returned to the lab 48 hours later and saw a series of 180 pictures -- the 90
originals were mixed in with 90 new photos. The control group recalled about 50
percent of the photos from the first session. Those who exercised remembered
about 60 percent.
"Our study
indicates that people don't have to dedicate large amounts of time to give
their brain a boost," said Lisa Weinberg, the Georgia Tech graduate
student who led the project.
Although the study
used weight exercises, Weinberg notes that resistance activities such as squats
or knee bends would likely produce the same results. In other words, exercises
that don't require the person to be in good enough to shape to bike, run or
participate in prolonged aerobic exercises.
While all
participants remembered the positive and negative images better than the
neutral images, this pattern was greatest in the exercise participants, who
showed the highest physiological responses. The team expected that result, as
existing research on memory indicates that people are more likely to remember
emotional experiences especially after acute (short-term) stress.
But why does it
work? Existing, non-Georgia Tech human research has linked memory enhancements
to acute stress responses, usually from psychological stressors such as public
speaking. Other studies have also tied specific hormonal and norepinephrine
releases in rodent brains to better memory. Interestingly, the current study
found that exercise participants had increased saliva measures of alpha
amylase, a marker of central norepinephrine.
"Even without
doing expensive fMRI scans, our results give us an idea of what areas of the
brain might be supporting these exercise-induced memory benefits," said
Audrey Duarte, an associate professor in the School of Psychology. "The
findings are encouraging because they are consistent with rodent literature
that pinpoints exactly the parts of the brain that play a role in
stress-induced memory benefits caused by exercise."
The collaborative
team of psychology and applied physiology faculty and students plans to expand
the study in the future, now that the researchers know resistance exercise can
enhance episodic memory in healthy young adults.
"We can now try
to determine its applicability to other types of memories and the optimal type
and amount of resistance exercise in various populations," said Minoru
Shinohara, an associate professor in the School of Applied Physiology.
"This includes older adults and individuals with memory impairment."
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