"Leaking" muscle cells are the cause of physical exhaustion
Scientists at Columbia University, working under the guidance of Dr. Andrew Marks, argue that there is much more in common between marathon runners who have reached the finish line and patients with chronic heart failure than one can imagine.
The results of their research indicate that the physical exhaustion experienced by marathon runners and other athletes at the end of grueling competitions or hours of daily training is caused by tiny "leaks" that pass calcium ions into muscle cells. This not only reduces the strength of muscle contractions, but also activates an enzyme that breaks down proteins and damages muscle fibers.
According to Marx, this does not mean at all that physical activity is harmful to the body. Scientists observed "leaking" muscle cells in experimental mice and athletes only after daily three-hour loads of high intensity for several days or weeks (depending on the magnitude of the load), leading to complete exhaustion. In addition, depleted muscles return to normal after a few days of rest, and cell damage is fully restored within a few days or weeks, depending on the severity of training.
To study the mechanisms of physical exhaustion during active sports, scientists were prompted by the results of earlier work, during which they observed a similar picture of the condition of the muscles of animals with heart failure. Unlike athletes, the muscles of patients with heart failure have no chance to recover, and patients constantly experience general weakness and malaise caused not by a deterioration in the supply of their tissues with blood and oxygen, but by the penetration of calcium ions into the cells, which reduces the ability of muscles to repeatedly contract.
As part of the work, the authors injected mice with an experimental drug blocking the penetration of calcium ions into myocytes before the start of a three-week experiment. In the control group mice, physical exhaustion occurred after three weeks of daily three-hour swimming. The experimental group animals remained energetic, and their muscles showed fewer signs of excess calcium ions, atrophy and cell damage.
The authors are already planning to conduct clinical trials in several medical centers on patients with heart failure. However, even if the test results demonstrate its ability to improve the condition of patients, it will take several more years for it to appear on the market.
Recently, physiologists have refuted a 100-year-old theory that the cause of muscle pain and weakness experienced by people after heavy physical exertion is the accumulation of lactic acid in the muscles. The results obtained by the authors provide a new explanation for these symptoms.
Portal "Eternal youth" www.vechnayamolodost.ru based on the materials of ScienceDaily
14.02.2008