Can Aerobic Exercise Help Diastolic Dysfunction?

When the heart beats, it squeezes and relaxes. The squeezing phase of the cycle is when the heart muscle contracts and ejects blood into the arteries and it is called systole. The relaxation phase is when the heart fills with blood to prepare for the next heartbeat and it is called diastole.

Sometimes, a stiffening of the heart muscle affects the diastolic phase of the heartbeat, making it more difficult for the relaxing heart muscle to completely fill with blood. This problem is known as diastolic dysfunction, which can eventually lead to diastolic heart failure. As some studies indicated, up to 75 percent of elderly women had diastolic dysfunction. While it is less common in men, its risk increases with age and studies have shown prevalence of 50 percent in men older than 70.

High blood pressure is the most common cause of diastolic dysfunction. Abnormal rhythms, fast heart rate, sudden increase in blood pressure, increased salt intake, excessive fluid consumption and insufficient blood flow to the heart muscles may stress the heart and lead to diastolic dysfunction.

Patients with diastolic dysfunction typically have a limited exercise capacity. They tend to complain of dyspnea (shortness of breath) easily on activities which they could do comfortably in the past. But recent evidence strongly suggests that a program of aerobic exercise can actually improve the symptoms of diastolic dysfunction and enhance quality of life. Patients may begin to reverse the stiffness of the heart muscle and prevent the onset of diastolic heart failure.

Randomized trials in patients with diastolic dysfunction have demonstrated that regular aerobic training (but not weight lifting or strength training) for 3 to 4 months can significantly improve exercise capacity, symptoms of shortness of breath with exertion, and quality of life measures. There is evidence indicating that strength training may worsen the problem by causing the heart muscle to hypertrophy (thicken) in a way that increases cardiac stiffness. Aerobic exercise, including walking, cycling, or jogging, is a form of exercise in which the energy demands of the muscles are met by consuming oxygen.

The latest findings published January 8, 2018 in journal ‘Circulation’ reported that exercise can reverse damage to sedentary, aging hearts and provide protection against future heart failure by preventing the increase in cardiac stiffness with sufficient exercise, and if it is begun in time. The study was conducted 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.

Researchers pointed out that heart stiffening often shows up in middle age in people who do not exercise and are not fit, leaving them with small, stiff chambers that cannot pump blood as well. At the end of the 2-year study, those who had exercised for 30 minutes 4 to 5 times a week 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. 

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Why Is Excessive Blood Clotting Dangerous?

As one gets a cut or wound, the body forms blood clots that help stop bleeding and slow blood loss. Proteins in the blood called fibrins work with small blood cell fragments called platelets, to form the clot. This is called coagulation. After bleeding has stopped and healing has occurred, the clots should be removed by the body. Sometimes blood clots form too easily or do not dissolve properly and travel through the body so as to limit or block blood flow. This is called excessive blood clotting or hypercoagulation. 

Hypercoagulation can be very dangerous. The blood clots formed can travel to the arteries or veins in the brain, heart, kidneys, lungs and limbs. This in turn can cause heart attack, stroke, kidney failure, venous thromboembolism (VTE), peripheral artery disease (PAD), pregnancy-related problems or even death. 

VTE includes deep vein thrombosis (DVT) and pulmonary embolism (PE). PE occurs when a blood clot travels from a deep vein in the body to the lungs. It can damage the lungs and other organs and cause low oxygen levels in the blood. Blood clots formed in a vein deep in the arm or leg can cause deep vein thrombosis (DVT). People with DVT feels pain, and have swelling, redness, or increased warmth in the affected limb. DVT clots can break off, travel to the lungs and cause PE. Peripheral Artery Disease (PAD) is a narrowing of the peripheral arteries, most commonly in the arteries of the pelvis and legs. Blood clots can also cause pregnancy-related problems like miscarriages, stillbirths, preeclampsia, which is high blood pressure that occurs during pregnancy.

The cause of hypercoagulation can be acquired, meaning it is triggered by another disease or condition. Examples include smoking, overweight and obesity, pregnancy, use of birth control pills or hormone replacement therapy, cancer, prolonged bed rest, or car or plane trips. It can also be due to genetic defects, though less common. These genetic defects usually occur in the proteins needed for blood clotting and can also occur with the substances that delay or dissolve blood clots. While these acquired and genetic sources are not related, one can have both.

Excessive blood clotting can be treated with medicines, but sometimes emergency treatment is required. Doctor would examine the size and location of the clots to decide on the kind of treatment needed. Emergency treatment to prevent blood clot that could lead to serious problems like stroke and heart attack involves medicines called thrombolytics or clot busters, which can quickly break up clots. These medicines can cause sudden bleeding, so they are only used to break up large blood clots in life-threatening situations.

In non-emergency situations, blood thinners or anticoagulants are prescribed to keep existing clots from getting bigger and to prevent new clots from forming. Usually, both heparin and warfarin are prescribed at the same time. Heparin is given as an injection or through an IV tube and it acts quickly. Warfarin in pills takes several days before it starts to work. Once the warfarin starts to work, the heparin is stopped.

What Is Isolated Systolic Hypertension?

One is said to have hypertension if he or she has a blood pressure of 140/90 mmHg or higher. 140 is the systolic blood pressure, the force on the arteries as the heart pumps blood, and 90 is the diastolic blood pressure, the force on them when the heart is resting.

Hypertension or more commonly known as high blood pressure can put extra strain on blood vessels and organs including the brain, kidneys and eyes. People with hypertension are at a higher risk of developing several chronic diseases including heart disease, stroke and kidney disease.

For some people, the systolic stays consistently at 140 or higher but the diastolic number is below 90, which is not in a hypertension range. The condition is called isolated systolic hypertension (ISH), which is the most common subtype of primary hypertension in people over the age of 50, as reported in a March 2015 article in ‘Journal of the American Society of Hypertension’. Primary hypertension, also known as essential hypertension, means there is no underlying medical condition to explain the hypertension. 

In the United States, it is currently estimated that more than 30 percent of women over 65 and more than 20 percent of men have ISH. People with a family history of hypertension are more likely to have it as they get older. It is also possible for younger people to be affected by ISH.

A study by doctors from UT Southwestern Medical Centre’s Hypertension program found that otherwise healthy young people aged 18 to 49 with ISH are at greater risk for future artery stiffening linked to an increased risk of stroke and possible damage to the kidneys and brain. The study, which was published May 15, 2017 in the journal ‘Hypertension’, examined 2,001 participants in the Dallas Heart Study, a population-based study of more than 6,000 adults in Dallas County in USA. The researcher also warned that the occurrence of ISH in Americans aged 18 to 39 more than doubles over the last 2 decades.

While the cause may not be completely understood, ISH is believed to be associated with 

age-related stiffening of the aorta (the main artery in the body) and narrowing of the smaller arteries. These changes cause the heart pump blood more forcefully through these vessels, increasing the systolic pressure. Other possible reasons include increased age, smoking, excess dietary sodium, alcohol abuse, obesity and inactivity.

There are very few initial symptoms, but as the condition worsens, symptoms may start to emerge. People with ISH may develop symptoms pain in the joints of the hands, racing heartbeat, dry eyes, blurry vision, leg cramps, sore throat, nocturia (nighttime urination), headaches and irregular heartbeat.

Medicine may need to be prescribed to bring the blood pressure down if the systolic blood pressure is too high. Some drugs used to control blood pressure may include diuretics (water pills) to help remove water and sodium from the body; beta-blockers to slow the heart beat and make the heart beat less forcefully; angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), or calcium channel blockers to relax the blood vessels; renin inhibitors to keep the kidneys from making a chemical that can lead to higher blood pressure.

Besides taking medications, patients may also be required to stop smoking if they are smokers, lower the amount of salt in the diet, cut back on alcohol for drinker, get to or stay at a healthy weight, and of course, exercise regularly.