Couch-potato workout pill? Not so fast
It sounded so good just three days ago. "You're getting the benefits of exercise without having to do any work," said David Mangelsdorf, a pharmacologist at University of Texas Southwestern Medical Center in Dallas, who was not connected with the research. That's what he told the Los Angeles Times in an Aug. 1 story about a chemical compound, known as AICAR, which allowed sedentary mice to run farther on a treadmill than their placebo-taking couch-mice peers. And when the mice were dissected, the ones who took AICAR had 29% more high-efficiency muscle fibers than those on a placebo.
As you can well imagine, rodents worldwide were popping out the good, high-fat cheese to celebrate. So were humans, even without proof the drug will ever have any benefit for their species.
So now here comes a killjoy, Frank Booth, a University of Missouri-Columbia researcher who has studied inactivity in humans for 40 years. It seems that changing the physical composition of muscle -- transforming the tissue from sugar-burning fast-twitch fibers to fat-burning slow-twitch ones -- as the chemical compound did for the mice, doesn't even get close to providing all the benefits of exercise.
Booth, in a news release from the university, lists 26 benefits of exercise not touched by the compound AICAR:
- Decreased resting heart rate
- Increased heart stroke volume at all exercise workloads
- Increased maximum 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 functioning of the cells lining blood vessels
- Decreased incidence of heart attack
- Less damage if you do have a heart attack
- Improved balance of oxygen in the blood
- Decreased inflammation
- Improved immune function
- Decreased fatty liver disease
- Reduced risk of Type 2 diabetes
- Improved psychological well-being
- Better cholesterol numbers
- Improved cognitive function in the elderly
- Improved blood flow in the brain
- Prevention of loss of brain volume in the elderly
- Delay in decline of multiple organ systems with aging
Looks like it's back to the old treadmill.
-- Susan Brink
Photo: Salk Institute, La Jolla. Lab mouse working out.