How Body Fat And Muscle Is Affected By Endurance Running

To examine how endurance runners’ bodies reacted to the conditions of running for an extended period of time, researchers followed them for 2 months over a 4,500-kilometer course making use of a mobile MRI unit.

A huge amount of unique data was acquired regarding how the body’s body fat and muscle is affected by endurance running. A lot of the data collected is also applicable to the average runner.

Samples of blood and urine and also biometric data were gathered from 44 runners daily. They were also given other exams randomly, such as electrocardiograms, throughout the duration of the study. A whole-body MRI exam was administered to 22 of the runners approximately every 3 or 4 days throughout the race, 15 to 17 exams in total during a 64 day period. When the race finished, data was examined to determine, amongst other things, how endurance running affected stress-induced changes in the feet and legs. Measurements were taken of visceral fat, body fat, whole-body volume, abdominal subcutaneous adipose tissue, and lower extremity skeletal muscle and fat. State-of-the-art MRI techniques permitted the researchers to measure muscle tissue, cartilage and fat changes. The gold standard for evaluating runner’s musculoskeletal system is MRI.

The results revealed that an average of 5.4% body volume for the duration of the race was lost, the majority of being in the 1st 2,000 kilometers. 40% body fat was lost in the 1st half of the race and 50% during the course of the race. There was an average loss of 7% leg muscle volume.

It was found that regardless of the daily endurance running, the athletes’ leg muscles in fact degenerated due to the huge energy consumption.

While most individuals don’t run to this extreme, some of the other findings of the study are still significant for the recreational runner.

For instance, the results revealed that certain leg injuries can safely be “run through.” It’s usually possible to keep running with no risk of additional tissue damage if a runner has lower or upper leg intermuscular inflammation. Other injuries involving overuse, like joint inflammation, have more of a risk of progression.

One more important outcome of the research was that fat tissue was the 1st tissue impacted by running. Even more important, visceral fat loss took place a lot sooner in the running process than believed in the past. Visceral fat is associated with cardiovascular disease and is the most harmful fat. The results also showed that the largest amount of overall fat loss happened early on in the process.

When just starting to run, fat reduction effects are more pronounced compared to athletes who’ve been running their entire life. This sport should be done regularly over the years. If running is stopped for lengthy periods, caloric input needs to be reduced or alternative aerobic exercises chosen to prevent weight gain.

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References: PMID: 22812450