Today I'll point out a couple of recent research publications on the topic of the molecular mechanisms of exercise: how it might work to improve health, how it extends healthy life span but not maximum life span in animal studies, and how the response to exercise might be safely improved or otherwise manipulated. Researchers nowadays tend to comment on future directions for drug discovery based on their investigations of exercise, and in that this slice of the field is becoming much like calorie restriction research ten to fifteen years ago.
Take a moment to think about how much work and funding has gone into investigations of calorie restriction and the search for drug candidates that can mimic even just a fraction of the beneficial metabolic alterations and extension of healthy life spans that occur in response to calorie restriction: probably a few billion dollars and year after year of dedicated investigations by hundreds of scientists in the past decade alone. Yet at the end of all that, and after the collection of enormous amounts of data, there is only a small number of drug candidates, few of which are anything other than marginal in animal studies, none of which can reproduce all of the beneficial changes observed in calorie restriction, and there is still no comprehensive accounting of how calorie restriction works under the hood, just an outline of ever-growing complexity.
It has taken fifteen years to get that far. Processes like the reaction to restricted calorie intake and exercise are enormously complex. They impact near every aspect of metabolism and cellular biology, and the quest to understand them well enough to manipulate them is more or less the same thing as the quest to understand cellular biology completely. This and the past history of calorie restriction mimetic drug research is why I'm not holding my breath waiting on exercise mimetic drugs. Researchers will talk about this as a goal, just as they have talked about calorie restriction mimetic drugs, but the reality is that the inherent complexity involved makes this is a very long-term project, one that tends to produce marginal outcomes at great expense. Exercise mimetics and calorie restriction mimetics that are safe and reliable would be a pleasant thing to have around, to be sure, but it seems to me that at the present time there are better and more cost-effective approaches to the treatment of aging as a medical condition.
Excessive caloric intake and limited physical activity contribute to the current explosion of 'modern' chronic diseases such as obesity, type 2 diabetes, muscle atrophy, and cardiovascular diseases. By contrast, regular physical exercise maintains glucose homeostasis and induces physiological adaptations that effectively prevent, and often reverse, these diseases. Recognizing the human and economic burdens these diseases cause, and taking into account the health benefits of exercise, have led many exercise scientists to suggest that physical exercise may be the preferred method in the treatment and prevention of these 'modern' chronic diseases.
Unfortunately, exercise compliance levels are almost universally low, especially for people using home-based exercise programs. A variety of factors including poor physical condition, weakness, sickness, lack of time, and poor motivation contribute to low exercise compliance. The much publicized poor compliance begs the question: is there an alternative approach that both induces the health benefits of physical exercise and overcomes the problem of low compliance rate? Regular physical exercise activates a number of molecular pathways in whole organ systems and reduces the risk of developing numerous chronic diseases. Although nothing can fully substitute for physical exercise, candidate exercise pills that have emerged in recent years may be an attractive alternative.
Researchers exposed a thousand molecular changes that occur in our muscles when we exercise, providing the world's first comprehensive exercise blueprint. "Exercise is the most powerful therapy for many human diseases, including type 2 diabetes, cardiovascular disease and neurological disorders. However, for many people, exercise isn't a viable treatment option. This means it is essential we find ways of developing drugs that mimic the benefits of exercise." The researchers analysed human skeletal muscle biopsies from four untrained, healthy males following 10 minutes of high intensity exercise. Using a technique known as mass spectrometry to study a process called protein phosphorylation, they discovered that short, intensive exercise triggers more than 1000 changes.
"Exercise produces an extremely complex, cascading set of responses within human muscle. It plays an essential role in controlling energy metabolism and insulin sensitivity. While scientists have long suspected that exercise causes a complicated series of changes to human muscle, this is the first time we have been able to map exactly what happens. This is a major breakthrough, as it allows scientists to use this information to design a drug that mimics the true beneficial changes caused by exercise. Most traditional drugs target individual molecules. With this exercise blueprint we have proven that any drug that mimics exercise will need to target multiple molecules and possibly even pathways, which are a combination of molecules working together. We believe this is the key to unlocking the riddle of drug treatments to mimic exercise."