The research, published in the August edition of Clinical Endocrinology suggests a causal link between naturally occurring hormone levels and strengthening of the heart muscle in professional rowers. Elite rowers were found to have higher levels of insulin-like growth factor 1 (IGF-1) compared to healthy sedentary volunteers. In these athletes, IGF-1 values correlate with enlargement and strengthening of heart muscle cells.
Researchers, led by Dr Giovanni Vitale (University of Milan, Italian Auxologic Institute, Italy) and Professor Gaetano Lombardi (University of Naples Federico II, Italy), measured circulating IGF-1 levels in blood samples from 19 top-level male rowers and 19 age-matched healthy sedentary controls. IGF-1 is a hormone that is produced by the liver in response to growth hormone stimulation.
Each subject had their cardiac structure and function measured using standard echocardiography and ‘pulsed Tissue Doppler’, a more effective way of accessing and recording activity, particularly from the right side of the heart. For the rowers, examinations took place during a period of intense physical training, but at least 24 hours following the last athletic activity.
The rowers had higher serum IGF-1 levels compared to controls, but in both groups IGF-1 levels were within the normal range. The rowers’ hearts were also much larger, showing increased cavity dimensions, increased wall thickness, and enhanced muscle function, in both the left and right sides of the heart, compared to controls. In the rowers, IGF-1 levels correlated significantly with several echocardiographic parameters of myocardial contractility. Importantly, these associations remained significant when adjusted for age and heart rate. There were no significant differences in terms of height, weight and blood pressure between the two groups, although as expected, the rowers had significantly lower resting heart rates compared to the control group.
This is the first study to show an independent association between IGF-1 levels and remodelling of the right side of the heart in competitive rowers, and provides clues as to how the body responds and adapts to prolonged physical exercise. IGF-1 promotes muscle growth, and is known to be activated during exercise; IGF-1 levels often remain elevated following a training period1. This research provides a potential mechanism for cardiac remodelling in rowers, whereby an increase in IGF-1 may activate biochemical pathways, which trigger heart muscle growth, resulting in increased cardiac strength and output.
Researcher Dr Giovanni Vitale said:
“Cardiac hypertrophy, or enlargement of the heart muscle cells, is a hallmark of top athletes, especially rowers, and is a physical adaptation to increased cardiac load during prolonged periods of exercise. Our results show both the left and right sides of the rowers’ hearts are larger, and function at an enhanced capacity compared to those of the controls. The causes of this strengthening of athletes’ heart muscle are not completely clear. It could be due to the production of growth factors (such as IGF-1) during training. In fact, physical exercise is associated with cardiac haemodynamic changes (pressure and volume overload) able to stimulate the production of growth factors by stretching myocardial fibers.”
“To this end, we investigated levels of the hormone insulin-like growth factor-1 (IGF-1), and found significantly increased levels in the rowers compared to the control group, although in both groups IGF-1 levels were within the normal range. Furthermore, higher IGF-1 levels in the rowers’ bloodstream correlated significantly with better heart performance.
These results highlight a possible biochemical mechanism for cardiac hypertrophy in elite rowers and suggest a potentially beneficial role for IGF-1 in the remodelling of the heart muscle. This could mean that naturally increased production of IGF-1, occurring as an adaptation to prolonged training, influences biochemical processes that control contraction of the heart muscle in rowers. Further research is now needed to determine the exact relationship between higher production of IGF-1 and cardiac output in elite rowers.”
Rebecca Dixon | alfa
The end of pneumonia? New vaccine offers hope
23.10.2017 | University at Buffalo
Scientists track ovarian cancers to site of origin: Fallopian tubes
23.10.2017 | Johns Hopkins Medicine
Salmonellae are dangerous pathogens that enter the body via contaminated food and can cause severe infections. But these bacteria are also known to target...
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
23.10.2017 | Event News
17.10.2017 | Event News
10.10.2017 | Event News
23.10.2017 | Life Sciences
23.10.2017 | Physics and Astronomy
23.10.2017 | Health and Medicine