Putting on extra pounds may damage your mental, as well
as your physical, fitness but overweight middle-aged people who follow a
program of high-intensity interval training can lose weight and improve their
cognitive functioning. These are the
implications of two recent small studies, one headed by Timothy Verstynen, PhD
of Carnegie Mellon, the other by Dr. Anil Nigam of the University of Montreal
and the Montreal Heart Institute.
In the Carnegie Mellon study, researchers examined the
brains of 29 adults using functional magnetic resonance imaging. The subjects’ body mass index scores ranged
from normal to obese. In the overweight
and obese subjects there was evidence of hyper-connectivity in parts relating
to memory and decision-making, indicating that the brain needed to work harder
in those individuals. These parts
functioned normally in people of average weight. The obese subjects also needed more effort to
perform a decision-making task. “As people
put on unhealthy amounts of weight, the body’s energy systems begin to degrade
and you can start to see the negative effect on brain circuitry, particularly
areas that are important for controlling impulsive behaviors,” according to
Verstynen. The key factor seems to be
inflammation, which interferes with the body’s communication system.
The Canadian research involved six subjects in their late 40’s
with body mass index numbers in the “overweight” range. Dr. Nigam said, “We worked with six adults
who all followed a four-month program of twice weekly interval training on
stationary bicycles and twice weekly resistance training. Cognitive function, VO2max and
brain oxygenation during exercise testing revealed that the participants/
cognitive functions had greatly improved thanks to the exercise.” VO2max refers to the maximum
amount of oxygen that a person’s body can use during intense exercise; it is an
indicator of cardio-vascular fitness and aerobic endurance. Participants in the study lost inches around
the waist and reduced body weight but they also significantly improved
performance on cognitive tasks, such as remembering pairs of numbers and
symbols.
These studies suggest that exercise allows the body to recover
mental as well as physical functioning, even in middle age. Based on the descriptions I’ve read there
wasn’t a huge time commitment, just four sessions per week, but the exercise
was at a fairly intense level, interval training and weights. A leisurely walk might not have the same effect
on the brain, though it probably helps the body.