Prof Pooh-Poohs “Exercise Pill” Reports

By Will Parker on August 6, 2008 in News

An expert in exercise and the human metabolic system has criticized recent media stories about the invention of an “exercise pill” as unrealistic and largely ignorant of the benefits that physical activity has on human physiology.

The reports in question were based on the discovery, by researchers at The Salk Institute, of a substance that increased exercise endurance (in mice) without daily exertion. But Professor Frank Booth, from the University of Missouri School of Medicine, says the reports neglected to consider all of the commonly known benefits of exercise and the pill therefore cannot be considered a replacement for exercise.

In the study in question – “Exercise Mimetics” published in Cell – the Salk researchers demonstrated that AMPK-PPAR� pathways (a cellular messenging 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
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

Additionally, Booth says the prevention of the increased risk of chronic disease produced by lifelong physical inactivity also was not tested by the Salk team.

Booth’s contention, based upon 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 exercise pill is unlikely 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.