Human evolution; exercise helps the brain (Introduction)

by David Turell @, Friday, November 23, 2018, 21:03 (555 days ago) @ David Turell

We are still hunter-gatherers who evolved bodies to be maintained by exercise activities:

"Researchers have long recognized that exercise sharpens certain cognitive skills. Indeed, Maejima and his colleagues have found that regular physical activity improves mice’s ability to distinguish new objects from ones they’ve seen before. Over the past 20 years, researchers have begun to get at the root of these benefits, with studies pointing to increases in the volume of the hippocampus, development of new neurons, and infiltration of blood vessels into the brain. Now, Maejima and others are starting to home in on the epigenetic mechanisms that drive the neurological changes brought on by physical activity.


" Moses Chao, a molecular neurobiologist at the New York University School of Medicine, and colleagues recently found that mice that ran frequently on wheels had higher levels of BDNF and of a ketone that’s a byproduct of fat metabolism released from the liver. Injecting the ketone into the brains of mice that did not run helped to inhibit histone deacetylases and increased Bdnf expression in the hippocampus. The finding shows how molecules can travel through the blood, cross the blood-brain barrier, and activate or inhibit epigenetic markers in the brain.


"The result also offers support for the 58 clinical trials currently being done on exercise, cognition, and Alzheimer’s disease. There are nearly 100 ongoing trials, including Petzinger’s, investigating exercise’s role in easing Parkinson’s symptoms, and hundreds more looking at exercise as an intervention against depression. Some researchers are even testing the effects of exercise on aging.

“'An active lifestyle is not going to turn a 70-year-old brain into a 30-year-old brain,” says Petzinger. “But studying exercise’s effect on the nervous system could help researchers identify the best and most efficient strategy—whether it’s activity alone or activity paired with drugs—to maintain brain health as we age.'”

Comment: And the same thought applies to muscle health, since we are now not hunter-gatherers:

"In 1988, Tufts University’s Irwin Rosenberg coined the term “sarcopenia” from Greek roots to describe this age-related lack (penia) of flesh (sarx). Muscle aging likely has several underlying factors, including decreased numbers of muscle stem cells, mitochondrial dysfunction, a decline in protein quality and turnover, and hormonal deregulation. Loss of muscle mass is associated with—and possibly preceded by—muscle weakness, which can make carrying out daily activities, such as climbing stairs or even getting up from a chair, difficult for many seniors. This can lead to inactivity, which itself leads to muscle loss at any age. Thus, older people can enter a vicious cycle that will eventually lead to an increased risk of falls, a loss of independence, and even premature death.

"The good news is that exercise can stave off and even reverse muscle loss and weakness. Recent research has demonstrated that physical activity can promote mitochondrial health, increase protein turnover, and restore levels of signaling molecules involved in muscle function. But while scientists know a lot about what goes wrong in aging, and know that exercise can slow the inevitable, the details of this relationship are just starting to come into focus.


"Although the causes of muscle loss are numerous and complex, there is now copious evidence to suggest that exercise may prevent or reverse many of these age-related changes, whereas inactivity will accelerate muscle aging. Earlier this year, for example, Janet Lord of the University of Birmingham and Steven Harridge at King’s College London examined the muscles of 125 male and female amateur cyclists and showed that a lifetime of regular exercise can slow down muscle aging: there were no losses in muscle mass or muscle strength among those who were older and exercised regularly. More surprisingly, the immune system had not aged much either.

"Exercise’s influence on muscle health likely acts through as many mechanisms as those underlying age-related muscle loss and weakness. For example, the number of satellite cells can be increased by exercise, and active elderly people have more of these cells than more-sedentary individuals do. This is the reason why exercise prior to hip and knee surgery can speed up recovery in the elderly.

"Physical activity also affects the muscle’s mitochondria. A lack of exercise decreases the efficiency and number of mitochondria in skeletal muscle, while exercise promotes mitochondrial health.


"For now, regular exercise combined with good nutrition is still the most effective way to fight sarcopenia, and possibly aging overall."

Comment: The articles are filled with biochemical studies, if interested.

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