Exercise as it relates to Disease/Safe Exercise for Gestational Hypertension

Cardiovascular disease (CVD) is one of the leading causes of death in Australia, accounting for 34% of all deaths in 2007-08. The 2007-08 National Health Survey (NHS) reported Hypertension as the most common CVD, reported by 9% of the population. The Australian Bureau of Statistics (ABS) reported CVD as the highest health expenditure of all disease groups, accounting for 11.3% of Australia’s total allocated health spending

Hypertension is a cardiovascular disorder characterised by a systolic blood pressure of at least 140 mmHg and/or a diastolic blood pressure of at least 90 mmHg. To avoid ‘white coat’ hypertension, it is commonly measured using 24 hour ambulatory methods. Gestational hypertension is the new-onset of hypertension, typically presenting 20 weeks after gestation, and involves little to no urine protein content. Some women progress from Gestational hypertension to Preeclampsia. Preeclampsia is defined as gestational hypertension, plus proteinuria (300 mg or more per 24-hourperiod). This complication occurs in roughly 2-8% of women but however is manageable upon early detection. A complication exists here because physical symptoms often present late or not at all. Literature has reported that insulin resistance in early stages of pregnancy may serve as predisposition marker for gestational hypertension.

Pregnancy and Hypertension
Gestational hypertension is different to pre-existing Hypertension; however both carry risks for the mother and the baby. Hypertension in pregnancy can cause strokes, seizures, renal damage and cardiovascular disease. Different demographics will experience higher instance of hypertension during pregnancy. The Australian Bureau of Statistics (ABS) found that in 2008, 14% of birth-mothers of Aboriginal and Torres Strait Islander high blood pressure during their pregnancy.

Foetal Risk
Due to the high pressure in the vascular network, capillary walls are damaged and blood flow is hampered. Neural tube defects and lack of blood flow can also cause maternal hyperthermia. Capillaries to the womb and placenta carrying blood and therefore oxygen and nutrients to the foetus are therefore not efficient. Sufficient blood flow is needed to ‘feed’ the growing foetus. Complications here can result in poor growth, pre-term birth or even loss of pregnancy.

Treatment
Women diagnosed with Gestational Hypertension and/or Preeclampsia require close monitoring of both maternal and foetal conditions. Management of gestational hypertension includes: Commonly the mother’s blood pressure will return to normal within the first week postpartum. If blood pressure is still elevated, supplemented magnesium sulphate and antihypertensive drugs are given. Daily blood pressure measurements are conducted, until there are no signs or symptoms of hypertension.
 * Bed Rest
 * Blood Pressure Medications (anti-hypertensive drugs)
 * Foetal and Maternal Monitoring (daily blood pressure readings)
 * Hospitalisation (severe)

Exercise Prescription for Gestational Hypertension
Current literature suggests that women with gestational hypertension need to limit physical activity. However, the American College of Obstetricians and Gynaecologists (ACOG) listed pregnancy induced hypertension in a list for absolute contraindications to aerobic exercise during pregnancy. Literature suggests that regular physical activity within the first 20 weeks of gestation may prevent or reduce the risk of developing Hypertension and related hypertensive disorders during the latter period of gestation.

Hypertension and Exercise
Non aerobic-exercise such as yoga has been shown to decrease blood pressure in non-pregnant hypertensive patients. It has been suggested this and other antenatal exercises could also reduce the risk of developing gestational hypertension along with aerobic exercise preconception. Further research could be conducted into the effects of yoga and antenatal exercises on blood pressure in pregnant women to possibly predict the effects on pregnant hypertensive patients

Pregnancy and Exercise
Exercise should not involve ballistic movements or too much thermal/environmental stress. As the gestational period continues, exercise intensity can decrease as long as physical activity is maintained. Too much exercise or high intensity exercise causes skeletal muscle and the foetus to compete for blood flow and is related to pre-term births. Most studies predicted exercise intensity using % max heart rates varying depending on age and period of gestation. It is important to note that in healthy individuals, exercise during pregnancy is considered beneficial to both mother and foetus, and is encouraged. The American College of Sports Medicine (ACSM) recommend moderate intensity aerobic exercise for a minimum of 30 minutes per day.

Exercise during pregnancy with non-hypertensive subjects not only reduces the risk of developing hypertension but has a number of other benefits including: decreased adipose tissue accumulation associated with pregnancy due to increased sedentary activity, decreased labour pain, decreased triglycerides and inflammatory cytokines, decreased insulin resistance, enhanced placental growth and vascularity, increase in plasma volume and cardiac output, reduction in emotional stress and anxiety

Recommendations

 * Exercising with Gestational Hypertension is not encouraged as it only increases blood pressure and can causes damage to mother and foetus
 * Monitoring of blood pressure, rest and anti-hypertensive drugs are the main therapy for Gestational Hypertension
 * Best strategy is prevention through light aerobic exercise pre-conception and most importantly, during 1st half of pregnancy
 * Possible room for research into other coping strategies (non-aerobic exercise)
 * Contact your physician/obstetrician and seek medical evaluation and clearance before undertaking any exercise regime