How does Exercise Affect the Left Ventricular Systolic & Diastolic Heart Function in Sedentary Women?

Aerobic Exercises Such as Walking Work Wonders on Heart Health

Extra leg space, extra-large dresses, extra cheese pizzas and extra seating space in aircrafts have become a normalcy these days. We can see a greater number of obese/overweight individuals compared to those with a normal weight. Eateries and restaurants selling buttery chicken wings and juicy cheeseburgers have only been rising in proportion. Humans today live in a world where leading life has become easier due to technological advancements and scientific discoveries, all of which have led to a greater increase in global inactivity. Such inactivity has paved way for more and more people to engage in a sedentary lifestyle that prevails as one of the biggest health problems in today’s world. That’s because, the body becomes weak due to continuous inactivity and this reduces the resistance to various diseases such as type 2 diabetes, obesity, hypertension and coronary heart disease. Time and again health experts have been insisting on the importance of physical activity to ensure leading a healthy and nutritious life but we don’t bother to pursue such advices to ensure well-being of our body until some disease or infection strikes us.
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Cardiovascular disease is widespread worldwide and sadly, its not only the older generation but younger adults too who are becoming victims of this grave disease. Research shows that inactivity, rising obesity rates and lifestyle behaviors are serious threats to heart health and we do have positive research studies showing that cardiovascular risk factors greatly improve with heart-related changes that occur as a result of regular exercise sessions. Exercise is treated to be the nonpharmacological way of treating cardiovascular patients undergoing cardiac rehabilitation (CR) programs to improve their heart health and overall body fitness. Generally, all CR programs recommended heart patients to take up continuous moderate intensity aerobic training (CAT) such as walking and cycling as it is believed to reduce mortality rates, both cardia and other cause-mortalities. Generally, heart patients were always advised against performing strenuous exercise programs as it might be risky for the heart but of late, there have been more intense aerobic programs tested on cardiac patients that are proven to be safe and more effective than CAT in improving the patient’s overall cardiac outcomes. While aerobic training has been around for years, resistance training was not something that was a part of the exercise schedule of patients with heart conditions until the last two decades or so during which numerous advantages such as metabolic risk factors, functional capacity and psychological well-being were unraveled.

Left Ventricle’s Prominent Place in Determining Heart Health
Exercise training helps improving exercise capacity and cardiac output by increasing left ventricular functioning. There are studies that show that structural and functional changes in the left ventricle during exercise are prominently witnessed than changes in the other parts of the heart. Performing exercise elevates left ventricular stroke volume by increasing intrinsic cardiac contractility and improving left ventricular filling. The type of sport/exercise performed determines the framework adaptations in the left ventricle. Endurance training is one of the four types of exercises alongside strength, balance and flexibility that includes activities such as jogging, swimming, walking and cycling. Also known as aerobic training, practicing it regularly helps causing different changes in the structure and function of the heart and skeletal muscles. Resistance training helps in developing both left ventricular (LV) diastolic and systolic functions. Its been established that left ventricular training helps promote heart function but it would help further if we determine whether step-aerobic or core exercises help in improving left ventricular cardiac function development and also to minimize heart-related risk factors during middle age and beyond and the study below discusses this possibility.
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The study involved 45 healthy, sedentary women who were not involved in regular physical activity (more than 60 minutes a week), did not take any anti-pregnancy drugs, cigarettes or medications and were also devoid of diseases such as heart disease, respiratory, metabolic and inflammation disorders. Each of the participants were put into one of the two groups: step-up aerobic group (SAG) consisting of 25 participants and core exercise group (CEG) consisting of 20 participants. The study happened for four months and the exercise programs allocated for the two groups happened 4 days a week on all 16 weeks consecutively. Target heart rate (THR) was controlled using a heartbeat monitor and exercise intensity was also progressively increased every week from HR 60% to up to 70% (such as between 1st and 4th week it was HR 60%, between 5th and 8th week it was HR 65% and between 9th and 16th week it was HR 70%). Every exercise session happened for a full 60 minutes consisting of warm-up exercises (10 min), primary exercises (30-40 min, basic movements step-aerobic) and cool down exercises (10 min) in the case of SAG and for CEG warm up and cool down remained the same while primary exercises practiced for 40 minutes composed of core exercises that help in building more strength for lower and upper extremities that includes 3 sets/day, 10 repetitions/set with 1-2 minutes resting interval.

Height and weight measurements were taken, BMI readings were calculated, waist circumference, hip circumference and waist-to-hip ratio were also measured. BP measurements were taken and blood samples were taken in the morning after an overnight fast before and after the study. Two-dimensional echocardiography was performed before and after the 16-week study period, and variables such as LV end-diastolic dimension (LVDD), end-systolic dimension (LVSD), interventricular septum thickness (IVS), left ventricular posterior wall (LVPW) MDT-mitral deceleration time, left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) were measured.

Results showed that:

1. Comparisons before and after 16 weeks of exercise showed that there was substantial decrease in weight, BMI, fat mass, waist, hip, SBP and DBP values of SAG and CEG
2. Echocardiography taken after 16 weeks showed that left ventricular cardiac structural parameters of SAG improved better than CEG.
3. Left ventricular diastolic function was observed in Mitral A and Mitral E/A. Also, it was seen that left ventricular posterior wall parameter of CEG improved better than CEG
4. It was seen that CEG program helped better in improving hip value compared to SAG as core exercises provide more force production to the upper and lower limbs
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Regular step-aerobic and core exercises reduce the risk of cardiovascular disease in sedentary women while improving both, systolic and diastolic blood pressures. Left ventricular cardiac parameters and systolic function was observed in both exercise types and step-aerobic exercise improved left ventricular diastolic function more effectively.

Improving Left Ventricular Systolic & Diastolic Function in Adolescents with Type 1 Diabetes
Diabetes is one of the biggest public health problems that’s been attacking humanity inconsolably and the best means to curb this epidemic is to eat nutritious diets and exercise regularly. But what we lack is enough knowledge on whether exercise improves cardiac hemodynamics in adolescents with type 1 diabetes. Researchers have tried to analyze left ventricular volume at rest and also during exercise in individuals with type 1 diabetes compared to those without diabetes before and after a 20-week exercise training program. Adolescents aged between 14 and 18 years who were free of problems such as hypertension, neuropathy, retinopathy or microalbuminuria and suffered only from diabetes were involved in the study. 38 (20 males) participants with diabetes and 22 control participants were involved in the study. BMI, body composition, height, weight and abdominal obesity were measured. Exercise sessions lasted for 60 minutes each four times a week over a 20-week period. Exercises were modified to achieve 85% of the participant’s heart rate. During the 1st-12th week participants performed three days of aerobic exercises and one day of resistance training whereas from weeks 12-20 all of them were involved in 4 sessions of combined aerobic and resistance training. During the study period three participants dropped due to time commitments and finally only 72 participants remained: 37 of them with type 1 diabetes in exercise training group, 13 of them with type 1 diabetes in the control group and 22 adolescents without diabetes in the exercise training group.

Though both groups with diabetes increased total body weight it was more of fat-free mass compared to the control group with type 1 diabetes that gained weight due to fat deposition. The exercise sessions had a positive impact on body composition and helped in reducing percentage body fat and increasing fat free mass and bone mineral density. Exercise training had no impact on the resting and maximal exercise systolic, diastolic and mean arterial pressure but there was an increase in arterial pressure in the control group with type 1 diabetes after 20 weeks. The study showed that exercise improved the left ventricular function of both training groups at rest and also the submaximal exercise cardiac output, stroke volume, end-diastolic volume and ejection fraction. While improvements were witnessed in both training groups maximal effects were seen in the group with diabetes. Also, left ventricular filling and contractility improved after exercise training in adolescents with diabetes proving that exercise helps in preventing/postponing left ventricular function impairment in those patients with diabetes. Hence, this study clearly shows that regular practice of exercise over a period of 20 weeks was associated with improvements in left ventricular function. In trained teens with diabetes the results were similar to that achieved in untrained controls without diabetes.

References
The Effect of Exercises on Left Ventricular Systolic & Diastolic Heart Function in Sedentary Women: https://www.sciencedirect.com/science/article/pii/S1728869X17300953
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Exercise Training Improves but does not Normalize Left Ventricular Systolic & Diastolic Function in Adolescents with Type 1 Diabetes: https://care.diabetesjournals.org/content/40/9/1264