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'Exercise Pill' Is No Replacement For Real Exercise, Expert Cautions


ScienceDaily (Aug. 6, 2008) -- Recently, researchers at the Salk
Institute for Biological Studies, a research organization focused on
biology and its relation to health, published a study in the journal
Cell on the results of a substance that increased exercise endurance
without daily exertion when tested in mice. Media reports have
described this substance as an "exercise pill," potentially
eliminating the need for exercise.

Frank Booth, a University of Missouri expert on the science of
inactivity, says the "exercise pill" study did not test all of the
commonly known benefits of exercise and taking the pill cannot be
considered a replacement for exercise.

In the Cell paper "Exercise Mimetics" the researchers demonstrated
that AMPK-PPARä pathways, which is a cellular messenger system, can be
targeted by orally active drugs to enhance training adaptation or even
to increase endurance without exercise. However, Booth cautions that
some of the commonly known benefits of exercise were not tested in the
Cell paper including:

Decreased resting and submaximal exercise heart rate
Increased heart stroke volume at all exercise work loads
Increased maximal exercise cardiac output
Lower blood pressure and arterial stiffness
Increased aerobic capacity
A complete list of the 26 benefits not tested in the paper is included
below.

The prevention of the increased risk of chronic disease produced by
lifelong physical inactivity also was not tested in the Cell paper.
According to Katzmarzyk & Janssen (Can J Appl Physiol 29:90, 2004),
human physical activity decreases the risk of:

Coronary artery disease (decreases risk by 45 percent)
Stroke (decreases risk by 60 percent)
Hypertension (decreases risk by 30 percent)
Colon cancer (decreases risk by 41 percent)
Breast cancer (decreases risk by 30 percent)
Type 2 diabetes (decreases risk by 50 percent)
Osteoporosis (decreases risk by 59 percent)
Until targeting AMPK-PPARä pathways by drugs is shown to have all the
above listed exercise benefits in humans, it is premature to use the
term "exercise mimetics" from the very limited observations of the
Cell paper, Booth said. Booth's expectation, based upon his more than
40 years of research experience in exercise and physical inactivity
adaptations, is that the drugs in the Cell paper will only partially
imitate exercise. In order for any "exercise pill" to counter physical
inactivity, the pill must be polygenic, or control many genes at once;
therefore the Cell drugs are not likely to provide all of the benefits
of comprehensive physical activity. In Booth's opinion, the drugs used
in the Cell paper were not conclusively proven to mimic exercise,
contrary to media reports.

Booth has more than 40 years of research experience in physiological,
biochemical, molecular and genetic adaptations that occur during
exercise. He is a professor in the MU College of Veterinary Medicine
and the MU School of Medicine and a research investigator in the
Dalton Cardiovascular Research Center. He is a member of the editorial
boards of Journal of Applied Physiology, American Journal of
Physiology: Cell Physiology, Physiological Genomics and
CardioMetabolic Syndrome.

Commonly known benefits of exercise not tested in the Cell paper were:

Decreased resting and submaximal exercise heart rate
Increased heart stroke volume at all exercise work loads
Increased maximal exercise cardiac output
Lower blood pressure and arterial stiffness
Increased aerobic capacity
Increased strength and cross-sectional area of skeletal muscle
Delayed loss of muscle mass and strength with aging and physical
frailty
Improved balance and coordination
Improved flexibility
Reduced osteoporosis
Reduced joint stress and back pain
Decreased gallstone disease
Improved endothelial function
Decreased incidence of myocardial ischemia
Less myocardial damage from ischemia
Decreased oxidative stress
Decreased inflammation
Improved immune function
Decreased liver steatosis and fatty liver disease
Improved insulin sensitivity and reduced risk of type 2 diabetes
Less likelihood of depression, anxiety, stress and poor psychological
well-being
Ameliorating hyperlipidemia: lower total cholesterol, higher HDL, and
decreased blood triglycerides
Improved cognitive function in the elderly
Increased blood flow and neurogenesis in the dentate gyrus of the
hypothalamus
Prevention of the loss of brain volume in the elderly
Delay in decline of physiological reserve in organ systems with aging

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Adapted from materials provided by University of Missouri-Columbia.

University of Missouri-Columbia (2008, August 6). 'Exercise Pill' Is
No Replacement For Real Exercise, Expert Cautions. ScienceDaily.
Retrieved August 8, 2008, from

http://www.sciencedaily.com- /releases/2008/08/080805124013.htm