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'Exercise-In-A-Pill' Boosts Athletic Endurance By 70 Percent, Study Finds (sciencedaily.com)
An anonymous reader quotes a report from Science Daily: Salk Institute scientists, building on earlier work that identified a gene pathway triggered by running, have discovered how to fully activate that pathway in sedentary mice with a chemical compound, mimicking the beneficial effects of exercise, including increased fat burning and stamina. The study, which appears in Cell Metabolism on May 2, 2017, not only deepens our understanding of aerobic endurance, but also offers people with heart conditions, pulmonary disease, type 2 diabetes or other health limitations the hope of achieving those benefits pharmacologically. Previous work by the Evans lab into a gene called PPAR delta (PPARD) offered intriguing clues: mice genetically engineered to have permanently activated PPARD became long-distance runners who were resistant to weight gain and highly responsive to insulin -- all qualities associated with physical fitness. The team found that a chemical compound called GW1516 (GW) similarly activated PPARD, replicating the weight control and insulin responsiveness in normal mice that had been seen in the engineered ones. However, GW did not affect endurance (how long the mice could run) unless coupled with daily exercise, which defeated the purpose of using it to replace exercise. In the current study, the Salk team gave normal mice a higher dose of GW, for a longer period of time (8 weeks instead of 4). Both the mice that received the compound and mice that did not were typically sedentary, but all were subjected to treadmill tests to see how long they could run until exhausted. Mice in the control group could run about 160 minutes before exhaustion. Mice on the drug, however, could run about 270 minutes -- about 70 percent longer. For both groups, exhaustion set in when blood sugar (glucose) dropped to around 70 mg/dl, suggesting that low glucose levels (hypoglycemia) are responsible for fatigue.
I'm wondering why that genetic pathway isn't active for all mice, but suspect it's because they don't live as long during a famine. I also wonder why mice evolved to be able to run for 160 minutes straight, considering they tend to move in bursts, and hide.
Corruption is convincing someone that the selfless ideal is the same as their selfish ideal.
... they didn't evolve it as mice, it was already there when they evolved INTO mice and it presumably doesn't reduce their survivability (and even may help on rare occasions) so natural selection hasn't removed it.
If natural selection could have found a way of dramatically increasing our stamina and/or strength without reducing our lifespan or causing other issues that reduce our breeding ability
You don't even have to look for really nasty side effects. Most likely the steady state energy consumption of the body goes up when fitness is enhanced. Given a limited food supply, there's an optimum point on the fitness/energy curve. I assume the natural mice are already close to that optimum. When the environment changes, the optimum may shift, and the metabolism can quickly adapt, because the pathways are already there.