Korrekt træning kan vende tendensen til ældning af hjertet.

DALLAS – 8. januar 2018 – Motion kan vende skader, som skyldes stillesiddende livsstil med aldrende hjerte og forhindre risikoen for hjertesvigt – hvis det er tilstrækkeligt meget motion, og hvis det er påbegyndt i tide, ifølge en ny undersøgelse foretaget af kardiologer ved UT Southwestern og Texas Health Resources.

For at høste mest gavn bør træningsprogrammet begynde før 65 år, hvor hjertet tilsyneladende har bevaret en vis plasticitet og evne til at ombygge sig selv, ifølge resultaterne fra forskere ved Institut for Motion og Miljømedicin (IEEM), som er et samarbejde mellem UT Southwestern Medical Center og Texas Health Presbyterian Hospital Dallas.

Og øvelserne skal udføres fire til fem gange om ugen. To til tre gange om ugen var ikke nok, påviste forskerne i en tidligere undersøgelse.

"Baseret på en række undersøgelser udført af vores team i løbet af de sidste 5 år, er denne "dosis" af motion blevet min recept for livet," sagde seniorforfatter Dr. Benjamin Levine, institutleder og professor i intern medicin ved UT tex. "Jeg tror, at folk skal gøre dette som en del af deres personlige hygiejne – ligesom at børste tænderne og tage et bad."

Træning skal udføres fire til fem gange om ugen, generelt i 30-minutters sessioner, plus opvarmning og nedkøling:

En af de ugentlige sessioner omfatter en højintensiv 30-minutters træning, som f.eks. Aerobic-intervallet, hvor hjertefrekvensperioderne er 95 procent af toppunktet i 4 minutter, med 3 minutters perioder på lavere intensitet, gentaget fire gange (en såkaldt "4 x 4 ").

Hver interval-session bliver efterfulgt af en session med relativt lav intensitet.

En dags session varede en time og var af moderat intensitet. Denne længere session kunne være en sjov aktivitet som tennis, aerobic, dans, gåtur eller cykle.)

En eller to andre sessioner blev udført hver uge med moderat intensitet, hvilket betyder, at deltagerne ville svede, blive lidt kortåndede, men stadig være i stand til at holde en samtale – "taletest".

I undersøgelsen blev træningsforløb individuelt ordineret baseret på træningstest og pulsovervågning.

En eller to ugentlige styrketræninger med vægte eller motionsmaskiner blev inkluderet på en separat dag eller efter en udholdenhedssession.

Studiedeltagere blev bygget op på disse niveauer, der begyndte med tre, 30 minutters moderate træningssessioner i de første 3 måneder og toppede til 10 måneder, hvor to aerobic-intervaller med høj intensitet blev tilføjet.

De mere end 50 deltagere i undersøgelsen blev opdelt i to grupper, hvoraf den ene modtog to års overvåget træning og den anden gruppe, en kontrolgruppe, blot deltog i yoga og balancetræning.

Ved udgangen af den toårige undersøgelse viste det sig, at de, der havde udøvet træningen, havde en 18 procent forbedring i deres maksimale iltindtag under træning og en mere end 25 procent forbedring i elasticitet af hjerteets venstre ventrikulære muskel.

Levine sammenlignede forandringen i hjertet med et strakt, nyt gummiband i forhold til et, der var blevet stift af at ligge i en skuffe i lang tid.

Træningen kan også føre til forstærkning af musklerne i hjertets venstre ventrikel, kammeret, der pumper iltrigt blod tilbage til kroppen,

"Når musklerne stivner, får du et højt tryk, og hjertekammeret fyldes ikke så godt med blod. I sin mest alvorlige form kan blodet løbe tilbage i lungerne. Det er, når hjertesvigt udvikler sig," sagde Dr. Levine

Tidligere undersøgelser fra UT Southwestern kardiologer viste, at venstre ventrikulær stivhed ofte optræder i middelalderen hos mennesker, der ikke træner.

Forskerne fandt imidlertid også, at hjertekammeret i konkurrencedygtige mestre-niveau-atleter forbliver stort og elastisk, og at selv fire til fem dage med engageret motion over årtier er nok for ikke-konkurrencedygtige atleter at høste størstedelen af denne fordel.

I den nuværende undersøgelse ønskede forskerne at vide, om motion kan genoprette hjertets elastcitet hos tidligere stillesiddende individer – især hvis de er begyndt at træne i middelalderen.

Tidligere undersøgelser fra Dr. Levines forskningsprogram har vist betydelige forbedringer i hjerteoverensstemmelse hos unge personer efter et års træning, men overraskende lille ændring, hvis træningen blev startet efter 65 år.

For at starte undersøgelsen rekrutterede forskere 53 deltagere i alderen 45 til 64. Mange kom fra Dallas Heart Study, som omfatter 6.000 Dallas beboere og er det eneste single-center hjerteundersøgelse af sin størrelse og multietniske sammensætning.

Dallas Heart Study er designet til at forbedre diagnosen, forebyggelsen og behandlingen af hjertesygdomme.

Den nye undersøgelse er publiceret i Circulation, et tidsskrift fra American Heart Association.

IMAGE

IMAGE: DR. LEVINE, SHOWN HERE IN FRONT OF HIS LABORATORY'S HYPER/HYPOBARIC ENVIRONMENTAL CHAMBER, WHICH IS USED TO SIMULATE HIGH ALTITUDE, DEEP DIVING, AND SPACE-LIKE CONDITIONS IN STUDIES OF HUMAN PERFORMANCE…. view more

CREDIT: UTSW

EurekAlert! – Breaking News49

Proper exercise can reverse damage from heart aging

DALLAS – Jan. 8, 2018 – Exercise can reverse damage to sedentary, aging hearts and help prevent risk of future heart failure – if it's enough exercise, and if it's begun in time, according to a new study by cardiologists at UT Southwestern and Texas Health Resources.
To reap the most benefit, the exercise regimen should begin by late middle age (before age 65), when the heart apparently retains some plasticity and ability to remodel itself, according to the findings by researchers at the Institute for Exercise and Environmental Medicine (IEEM), which is a collaboration between UT Southwestern Medical Center and Texas Health Presbyterian Hospital Dallas.
And the exercise needs to be performed four to five times a week. Two to three times a week was not enough, the researchers found in an earlier study.
"Based on a series of studies performed by our team over the past 5 years, this 'dose' of exercise has become my prescription for life," said senior author Dr. Benjamin Levine, Director of the Institute and Professor of Internal Medicine at UT Southwestern. "I think people should be able to do this as part of their personal hygiene – just like brushing your teeth and taking a shower."
The regimen included exercising four to five times a week, generally in 30-minute sessions, plus warmup and cool-down:

• One of the weekly sessions included a high-intensity 30-minute workout, such as aerobic interval sessions in which heart rate tops 95 percent of peak rate for 4 minutes, with 3 minutes of recovery, repeated four times (a so-called "4 x 4").
• Each interval session was followed by a recovery session performed at relatively low intensity.
• One day's session lasted an hour and was of moderate intensity. (As a "prescription for life," Levine said this longer session could be a fun activity such as tennis, aerobic dancing, walking, or biking.)
• One or two other sessions were performed each week at a moderate intensity, meaning the participant would break a sweat, be a little short of breath, but still be able to carry on a conversation — the "talk test." In the study, exercise sessions were individually prescribed based on exercise tests and heart rate monitoring.
• One or two weekly strength training sessions using weights or exercise machines were included on a separate day, or after an endurance session.

Study participants built up to those levels, beginning with three, 30-minute, moderate exercise sessions for the first 3 months and peaked at 10 months when two high-intensity aerobic intervals were added.
The more than 50 participants in the study were divided into two groups, one of which received two years of supervised exercise training and the other group, a control group, which participated in yoga and balance training.
At the end of the two-year study, those who had exercised showed an 18 percent improvement in their maximum oxygen intake during exercise and a more than 25 percent improvement in compliance, or elasticity, of the left ventricular muscle of the heart, Dr. Levine noted. He compared the change in the heart to a stretchy, new rubber band versus one that has gotten stiff sitting in a drawer.
Sedentary aging can lead to a stiffening of the muscle in the heart's left ventricle, the chamber that pumps oxygen-rich blood back out to the body, he explained.
"When the muscle stiffens, you get high pressure and the heart chamber doesn't fill as well with blood. In its most severe form, blood can back up into the lungs. That's when heart failure develops," said Dr. Levine, who holds the S. Finley Ewing Chair for Wellness at Texas Health Dallas and the Harry S. Moss Heart Chair for Cardiovascular Research. He also holds the Distinguished Professorship in Exercise Sciences at UT Southwestern, which is celebrating its 75th anniversary this year.
Earlier research by UT Southwestern cardiologists showed that left ventricular stiffening often shows up in middle age in people who don't exercise and aren't fit, leaving them with small, stiff chambers that can't pump blood as well.
However, the researchers also found that the heart chamber in competitive masters-level athletes remains large and elastic, and that even four to five days of committed exercise over decades is enough for noncompetitive athletes to reap most of this benefit.
In the current study, researchers wanted to know if exercise can restore the heart's elasticity in previously sedentary individuals – especially if begun in late middle age. Previous studies from Dr. Levine's research program have shown substantial improvements in cardiac compliance in young individuals after a year of training, but surprisingly little change if the training was started after age 65.
To start the study, researchers recruited 53 participants, ages 45 to 64. Many came from the Dallas Heart Study, which includes 6,000 Dallas residents and is the only single-center heart study of its size and multiethnic composition. The Dallas Heart Study is designed to improve the diagnosis, prevention, and treatment of heart disease.
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The new study appears in Circulation, a journal of the American Heart Association. Collaborators on the study included first author Dr. Erin Howden, Research Fellow with UT Southwestern's Graduate School of Biomedical Sciences and the IEEM and now a faculty member at the Baker Heart and Diabetes Institute in Melbourne, Australia. Funding came from the National Institutes of Health and the American Heart Association.
About UT Southwestern Medical Center
UT Southwestern, one of the premier academic medical centers in the nation, integrates pioneering biomedical research with exceptional clinical care and education. The institution's faculty has received six Nobel Prizes, and includes 22 members of the National Academy of Sciences, 18 members of the National Academy of Medicine, and 14 Howard Hughes Medical Institute Investigators. The faculty of more than 2,700 is responsible for groundbreaking medical advances and is committed to translating science-driven research quickly to new clinical treatments. UT Southwestern physicians provide care in about 80 specialties to more than 100,000 hospitalized patients, 600,000 emergency room cases, and oversee approximately 2.2 million outpatient visits a year.

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