Tag: cardiovascular

Categories : AgeingTags :

Leg Motion Can Protect Against Leg Swelling in the Elderly

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A study from Kanazawa University in Japan has shown that leg swelling can be reduced in the elderly as the muscle pumping action of the leg is as effective in people of all ages.

Chronic lower-limb oedema (CLO) — the permanent accumulation of fluid in the leg — often occurs in elderly people. The condition leads to various physical and mental problems, including difficulty in walking or moving, fatigue and anxiety. Lack of physical activity, associated with a decrease in muscle pump action is one of the causes of CLO.

Leg muscles can act as a blood pump: when contracted, the muscle squeezes veins together, forcing blood to flow. But it was not known whether muscle pump action changes as people age had not been thoroughly investigated. Now, Junko Sugama from Kanazawa University and colleagues have addressed this issue. In addition, they studied the effect of leg posture on the muscle pump action.

For their study, the researchers recruited 76 healthy volunteers, categorised into young, middle-aged and old, with average ages of 24, 47 and 72 years, respectively. To investigate blood flow and visualise the morphology of muscles and veins at a given position along the leg, the researchers used MRI cross-section images at 21 positions in the calf region.

To assess the effect of leg motion, subjects were asked to perform plantar flexion (pointing the foot downwards) every 2 seconds for a minute, and MRI images were taken before and after the exercise. This procedure was repeated over three different body positions: supine, sitting and standing.

The scientists found that for all postures, blood flow increased after the exercise, implying that the latter promotes muscle pump action. The blood flow velocity was observed to increase most for the standing posture (90-135%), followed by the supine (55-90%) and sitting (30-40%) postures. No age difference was seen in the flow changes, however the elderly patients had exercise habits, the researchers pointed out.

The researchers suggested that nurse measurement of muscle pump action is useful for deciding whether intervention exercise is necessary to prevent CLO but an easier measurement tool than MRI is needed.

Additional studies are needed, such as adapting the measurement equipment so that it can be applied to elderly people with reduced mobility. The scientists nevertheless concluded that for their set of subjects, “no difference was found in the changes in muscle pump action with age”, and that “elderly people may be able to maintain their muscle pump action when they have exercise habits”.

Source: News-Medical.Net

Journal reference: Fujii, T., et al. (2021) Gravity magnetic resonance imaging measurement of muscle pump change accompanied by aging and posture. Japan Journal of Nursing Science. doi.org/10.1111/jjns.12407.

Categories : General InterestTags :

Russian Doctors Perform Heart Surgery in Burning Hospital

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Russian doctors stayed behind in a burning hospital to complete open-heart surgery on a patient after a fire broke out on the roof while they were operating.

It took firefighters over two hours to put out the blaze in the city of Blagoveshchensk. Using fans to keep smoke out of the operating room where a group of eight doctors and nurses was working on the patient, they also ran a power cable in to keep it supplied with electricity.

The heart bypass operation was finished in two hours before removing the patient to another site, the emergencies ministry said.

“There’s nothing else we could do. We had to save the person. We did everything at the highest level,” surgeon Valentin Filatov was quoted as saying by REN TV. 

According to the ministry, when the fire broke out on the roof,  128 people were immediately evacuated from the hospital, which is extremely old. There were no reported injuries.

“The clinic was built more than a century ago, in 1907, and the fire spread like lightning through the wooden ceilings of the roof,” the ministry said. The fire was believed to have been started by a short circuit. The hospital is the only one in the region with a specialist cardiological unit.

“A bow to the medics and firefighters,” said the local regional governor, Vasiliy Orlov.

Source: Reuters

Categories : Cardiovascular DiseaseTags :

Study Reveals Additional Pathway From Brain to Cardiovascular System

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Researchers at  University of Tsukuba in Japan have uncovered a previously unknown pathway from the brain to the cardiovascular system.

Though the cardiovascular system has a degree of autonomy to allow their independent functioning from the brain, the brain still has some control over it in order to respond to life-threatening situations. This control is exerted through the sympathetic and parasympathetic systems of the autonomic nervous system.

“From an evolutionary standpoint, the brain has had an incredibly important function in protecting the individual from predators,” says the lead author of the study Professor Tadachika Koganezawa. “But even in the absence of predators, our bodies react to stressful situations. In this study, we wanted to determine how the brain regulated the cardiovascular system via the autonomic nervous system.”

Located deep within the brain, the lateral habenula (LHb) has been known to elicit strong behavioural and cardiovascular responses to stressful events. But how it did so was still unclear. so to find out the researchers electrically stimulated the LHb in rats. This resulted in bradycardia and increased mean arterial pressure (MAP). The researchers then turned off the parasympathetic system by means of cutting the main parasympathetic nerve, the vagal nerve, or using a drug to antagonise it. 
Though this suppressed the LHb’s effect on the heart rate, the MAP was unchanged. Antagonising the sympathetic system had the opposite effect—decreasing the MAP but there was no effect on the heart rate.

To understand the mechanism by which the LHb elicits these cardiovascular responses, the researchers focused on the neurotransmitter serotonin, which plays an important role in the brain in modulating mood, cognition, and memory, among other functions.

While blocking all serotonin receptors significantly reduced the LHb’s effect on both the MAP and heart rate, the researchers found that specific subtypes of serotonin receptors were particularly involved in the process.

“These are striking results that show how the lateral habenula controls the cardiovascular system,” said study author Professor Masayuki Matsumoto , University of Tsukuba. “Our results demonstrate the mechanism of a neural circuit that plays an important role in stress-induced behavioral responses.”

Source: News-Medical.Net

Journal information: Doan, T. H., et al. (2021) Lateral Habenula Regulates Cardiovascular Autonomic Responses via the Serotonergic System in Rats. Frontiers in Neuroscience. doi.org/10.3389/fnins.2021.655617.

Categories : ExerciseTags :

Intense Exercise Needed to Prevent Heart Changes in Space

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A study of an astronaut and an extreme long distance swimmer has shown that intense exercise is needed to prevent heart changes in space or situations of reduced weight, such as water immersion.

By comparing data from astronaut Scott Kelly’s year in space aboard the International Space Station and comparing it to information from Benoît Lecomte’s  extreme long distance swimming, which simulates weightlessness, researchers found that low-intensity exercise was not enough to counteract the effects of prolonged weightlessness on the heart.

In a sitting or standing position, gravity draws blood into the lower extremities, and removing this effect through water immersion, prolonged bed rest or zero gravity conditions causes the heart to shrink as it no longer has to pump against this effect. Researchers have used the lack of gravity in space to investigate the physiology of ageing and muscle and bone loss, and vice versa.

Researchers examined data from retired astronaut Scott Kelly’s year-long mission aboard the ISS from 2015 to 2016 and elite endurance swimmer Benoît Lecomte’s swim across the Pacific Ocean in 2018.

In this new study, researchers evaluated the effects of long-term weightlessness on the structure of the heart and to help understand whether extensive periods of low-intensity exercise can prevent the effects of weightlessness.

“The heart is remarkably plastic and especially responsive to gravity or its absence. Both the impact of gravity as well as the adaptive response to exercise play a role, and we were surprised that even extremely long periods of low-intensity exercise did not keep the heart muscle from shrinking,” said senior author Benjamin D Levine, MD, and a professor of internal medicine at UT Southwestern Medical Center and director of Texas Health Presbyterian’s Institute for Exercise and Environmental Medicine.

The research team examined medical data from Kelly’s year aboard the ISS and Lecomte’s swim across the Pacific Ocean to investigate the impact of long-term weightlessness on the heart. Water immersion is an excellent model for weightlessness since water offsets gravity’s effects, especially in the prone swimming technique used by long-distance endurance swimmers.

As part of the routine countermeasures to maintain physical fitness in space, Kelly exercised six days a week, one to two hours per day using a stationary bike, a treadmill and resistance activities. Researchers hoped Lecomte’s 159-day 2700km swim from Choshi, Japan, with almost six hours a day of swimming, would keep his heart from shrinking and weakening. Doctors performed various tests to measure the health and effectiveness of both Kelly’s and Lecomte’s hearts before, during and after each man embarked on his respective expeditions.

Both men and Lecomte lost mass from their left ventricles (Kelly 0.74 grams/week; Lecomte 0.72 grams/week). They also suffered an initial shrinkage in the diastolic diameter of their heart’s left ventricle (Kelly’s dropped from 5.3 to 4.6cm; 5 to 4.7cm for Lecomte).

Even the most sustained periods of low-intensity exercise were not enough to counteract the effects of prolonged weightlessness. Left ventricle ejection fraction (LVEF) and markers of diastolic function did not consistently change in either individual throughout their campaign.

Due to its exceptional nature, more study is required to understand how these results can be applied to the general population. 

Lecomte had cardiac MRIs from before and after his swim and analysis of these is forthcoming. These will be helpful for the researchers to further understand whether long-term effects of weightlessness are reversible. Kelly did not receive cardiac MRIs, and currently, there are no further follow up plans for him.

Source: Medical Xpress

Journal information: Circulation (2021). DOI: 10.1161/CIRCULATIONAHA.120.050418