Hypertension Flashcards
What is hypertension?
Hypertension is a condition where blood pressure is consistently elevated above normal levels (>140/>90 mmHg).
What is normal vs. hypertensive blood pressure?
Normal BP: <120/<80 mmHg
Hypertension: >140/>90 mmHg
Why is hypertension often called the “silent killer”?
It usually has no symptoms, making early diagnosis difficult and leading to low diagnostic rates.
How does hypertension impact health over time?
Damages blood vessels, heart, and kidneys.
Increases the risk of heart disease, aneurysm, stroke, and kidney failure.
Raising systolic BP increases stroke mortality.
How does body weight influence blood pressure?
More body fat requires more blood vessels (~400 miles per extra pound), increasing total blood volume and BP.
How is blood pressure related to blood volume and resistance?
Higher blood volume = higher BP
Increased resistance (narrower arteries, longer travel distance) = higher BP
What are the 2 nervous system controls of blood pressure?
Medulla oblongata (brainstem): Regulates heart rate and vessel constriction.
Baroreceptors: Detect BP changes and send signals to adjust vessel dilation.
What hormones regulate blood pressure, and how do they function?
Renin-Angiotensin-Aldosterone System (RAAS): Increases BP by retaining sodium and water.
Epinephrine & Norepinephrine: Increase BP during stress.
Antidiuretic Hormone (ADH/Vasopressin): Retains water to raise BP.
Atrial Natriuretic Peptide (ANP): Lowers BP by promoting sodium excretion.
How does diet play a role in managing hypertension?
First-line therapy before medication in uncomplicated cases.
Works best when hypertension is caused by modifiable lifestyle factors.
How does sodium intake influence blood pressure?
High sodium increases blood osmolarity, pulling water into the bloodstream and increasing blood volume and BP.
Sodium is regulated by RAAS (retains Na+) and ANP (excretes Na+).
How does potassium intake affect blood pressure?
Higher potassium intake is associated with lower BP.
Potassium counteracts sodium’s effects, helping to balance BP regulation.
What is the DASH diet, and how does it help hypertension?
Emphasizes: Vegetables, fruits, low-fat dairy, whole grains, fish, poultry, beans, nuts, and vegetable oils.
Limits: Sodium, red meat, sweets, sugary drinks, and trans/saturated fats.
Shown to lower BP and reduce chronic disease risk (heart disease, stroke, osteoporosis).
How much sodium is in salt?
Salt is 40% sodium by weight, meaning 1 teaspoon = 2300 mg sodium.
What are the sodium intake recommendations for adults?
Adequate Intake (AI): 1500 mg/day (ages 9-50).
Upper Limit (UL): 2300 mg/day (ages 14-50).
Target intake to reduce hypertension: 1200 mg/day.
How much sodium do most Canadians consume?
85% of men and 60-80% of women exceed the UL.
Young adults (19-30 years) have the highest sodium intake (~4000 mg/day).
92% of children exceed AI, and 85% exceed UL due to processed foods.
Where does most sodium in the Canadian diet come from?
Processed foods (largest contributor).
Naturally occurring sodium.
Salt added at the table.
Salt added during cooking.
How does sodium intake relate to CVD risk?
Higher sodium intake = higher BP = increased CVD risk.
Reducing sodium by 1800 mg/day could lower hypertension prevalence by 30%.
Why is there debate about sodium reduction in public health?
Some studies show no effect or increased mortality at very low sodium intakes.
Sodium response is individualized (salt-sensitive vs. salt-resistant populations).
Possible confounding factors (e.g., people reducing sodium may already be at high risk).
What is salt sensitivity, and why does it matter?
Salt-sensitive individuals: BP is significantly affected by sodium intake.
Salt-resistant individuals: BP does not change much with sodium intake.
Factors influencing salt sensitivity: Age, race, potassium intake, and RAAS system.
What are 4 potential limitations of studies on sodium and CVD?
Observational studies: Cannot establish causation.
Reverse causation: High-risk individuals may already be limiting sodium intake.
Measurement errors:
Urinary sodium excretion: Affected by hydration, sweat loss, and incomplete collection.
Dietary recall/FFQ: Inaccuracies in portion estimation and sodium content in food databases.
Short-term studies: Underestimate long-term BP effects.
What is the J-curve hypothesis regarding sodium intake?
Some studies suggest moderate sodium intake may be most protective, with both high and very low sodium levels increasing CVD risk.
What sodium intake levels are associated with increased CVD risk?
> 5 g/day sodium (≈12.5 g salt): Increased CVD risk.
Moderate sodium intake: Conflicting evidence on CVD risk.
Low sodium intake (<1.5 g/day): Some studies show higher mortality, but more research is needed.
What are 4 key dietary strategies to prevent and manage hypertension?
Reduce sodium intake (target: 1200 mg/day).
Increase potassium intake (fruits and vegetables).
Follow the DASH diet (low sodium, high fiber, healthy fats).
Maintain a healthy weight and engage in physical activity.
Why is individualized sodium reduction important?
Not everyone responds the same to sodium reduction. Personalized approaches based on genetics, lifestyle, and overall health may be needed.
