Hypertension

Definition: Hypertension, also known as high blood pressure, refers to a condition where the blood exerts greater than normal force against the inner walls of the blood vessels.
Nickname: Often referred to as the "silent killer" due to mild symptoms until serious health issues arise.
Consequences: Can lead to significant damage to vital organs including the heart, brain, kidneys, and eyes, primarily due to circulatory issues related to blood vessel damage. Major risks involved include death by stroke or heart attack.

Primary Causes:
- Increase in Stroke Volume: This refers to the amount of blood the heart pumps with each beat. An increase in stroke volume directly contributes to higher blood pressure.
- Increase in Peripheral Resistance:
- Decreased Vasodilation: Resistance from blood vessels due to thickening arterial walls which become inelastic and less responsive, thus increasing blood flow resistance.
Conclusion: Either of these two mechanical causes, if sufficient, can lead to increased blood pressure.

Variability by Age: The incidence of hypertension significantly varies with age.
Statistics from Canada:
- Approximately 20-25% of Canadians are affected by hypertension.
- 1/3 of these individuals are unaware of their condition.
Symptoms: Typically, mild and moderate hypertension presents no symptoms. When severe, it can manifest with symptoms such as blurred vision, severe headaches, and confusion.
Statistics Reference: Data sourced from Statistics Canada pertaining to high blood pressure diagnosis prevalence by age group and sex.

Sphygmomanometer: Used to measure blood pressure, providing two key readings:
- Optimal Blood Pressure: Approximately 120/80 mmHg
- 120 mmHg: Systolic pressure (pressure during heart contraction).
- 80 mmHg: Diastolic pressure (pressure during heart relaxation).

Factors Cause Temporary BP Rise: Activities or factors such as stress, smoking, exercise, and caffeine can cause fluctuations.
Seasonal Variations:
- Blood pressure generally rises in winter (due to cold temperatures causing vessel constriction) and decreases in summer.
Weight Gain: Increased caloric intake and decreased physical activity during colder months contribute to these variations.

Primary or Essential Hypertension:
- Represents about 90% of hypertension cases where no specific medical cause can be identified. It is believed to be approximately 50% genetic and 50% environmental.
Secondary Hypertension:
- Factors associated include pregnancy, coarctation of the aorta, obesity, smoking, physical inactivity, high-fat diets with excess sodium intake, excessive alcohol consumption, and stress.

Effect on Arteries: High blood pressure can lead to swelling and stretching of artery walls.
Endothelial Injury: Creates conditions favorable for the accumulation of LDL cholesterol and white blood cells (WBC), significantly increasing the risk for stroke and heart attacks due to plaque formation (atherosclerosis).

Classification and Handling for Children: Risk factors include obesity, poor nutrition, and family history. Guidelines for managing blood pressure consider different stages and severity.
Blood Pressure Categories must be clearly understood, particularly when systolic and diastolic pressures fall into different stages; the higher stage is to be selected.

Normal Response:
- During aerobic exercise, systolic blood pressure typically rises between 30-60 mmHg with diastolic pressure remaining relatively unchanged.
Aerobic Training:
- Regular aerobic exercise can reduce systolic blood pressure by 5-7 mmHg and diastolic BP by 3-5 mmHg.
Dynamic Resistance Training: Shows a decrease of 2-3 mmHg in both systolic and diastolic pressures.
Isometric Resistance Training: Considered not recommended due to increased risks of medical complications from excessive spikes in blood pressure during exercise.
Clinical Implications: Reductions in systolic and diastolic pressure have been associated with decreases in stroke risk (14% and 17%, respectively) and coronary artery disease (9% and 6%, respectively).

Study Overview: Subjects with a body mass index (BMI) over 25 kg/m^2 participated in a 20-week supervised diet program.
- Result: BMI decreased from 31.9 kg/m^2 to 28.2 kg/m^2 and overall weight reduced by 11.5%.
Outcomes:
- Lower systolic BP noted at rest and during exercise.

Program Design:
- Type: Endurance training focusing on large muscle groups.
- Frequency: 3 to 7 days per week.
- Duration: 20-60 minutes.
- Intensity: 50-85% of peak heart rate; lower intensities of 40-70% are also beneficial.

Contraindications for Exercise:
- Resting blood pressure exceeding 180/110 mmHg and exercise-induced blood pressure exceeding 250/115 mmHg should avoid high-intensity activities.
Medication Effects: Consider how antihypertensive medications impact blood pressure during and after exercise, particularly in relation to peripheral resistance and post-exercise hypotension.

Primary Goals: To maintain blood pressure below 130/80 mmHg while using the least invasive methods. Recommended strategies include:
- Medications: Various classes are prescribed to control hypertension.
- Dietary Recommendations: Emphasize fruits, vegetables, low-fat dairy, and reductions in dietary salt.
- Exercise: Regular physical activity is essential.
- Stress Management: Effective control of emotional stress.
- Weight Control: Essential for overall management.

Beta Blockers: Work by blocking nervous and hormonal signals that contribute to heart and blood vessel activity to lower blood pressure.
Diuretics (Water Pills): Help lower blood pressure by flushing out excess water and sodium, often sufficient for stage 1 hypertension management when combined with lifestyle alterations.
Calcium Channel Blockers: Prevent calcium absorption in cardiac and vascular smooth muscle cells, causing relaxation and, consequently, lowering blood pressure.