HEA 201 Chapter 9, Fall 2007

Cardiovascular Diseases 1. Heart anatomy & circulation  Human heart = 4 chambers: 2 atria + 2 ventricles - Right part: receives deoxygenated blood from body tissues - Left part: pumps oxygenated blood to body tissues through the aorta 2. Cardiovascular diseases Hypertension  Blood pressure = result of  contraction & resistance of vessels  Reading: systolic ( contracts) / diastolic ( relaxes), in mm Hg  Hypertension:  blood pressure, e.g. because of blood vessel constriction  Consequences of hypertension - Extra effort of the heart  must work harder to pump enough blood in narrowed vessels may lead to heart failure - Damage to vessels damage of delicate tiny vessels in eye, kidney, brain… rough spots on which fat can start depositing  atherosclerosis ( diameter) Atherosclerosis  Hardening/narrowing of arteries because of fat deposits (plaque) on walls  Blood clot may form on top of plaque and block the vessel  Continuous process that can start in childhood  Fats that deposit on walls of vessels are LDL - LDL = “bad cholesterol” because can stick to arteries & clog them (LDL =>  risk of atherosclerosis) - HDL = “good cholesterol” because bring back excess cholesterol to liver ( HDL =>  risk of atherosclerosis)  Consequences of atherosclerosis: Deprives vital organs of blood  cells deprived of nutrients & O2 die blockage of a heart-nourishing artery (coronary)  heart attack blockage of a brain-nourishing artery  stroke Heart attack  Blocked  artery   O2 & nutrients supply   muscle begins to die  Artery blocked by clot, plaque or spasm  Warning signs include - Heavy pain/discomfort in the chest - Pain that may radiate to shoulder, arm, neck, back & jaw - Dizziness/fainting, shortness of breath, sweating Stroke  Blood supply to a portion of the brain restricted or blocked  cell death  Cause: clot, rupture of weakened artery…  Damage slight/severe, temporary/permanent depending on - Size/nature of the damage area - How much other areas can take over the functions of the damaged area  Possible signs include - Dimness/loss of vision - Difficulty speaking or understanding - Sudden loss of strength, numbness… 3. Risk factors  Sedentarity Exercise helps: maintaining desirable body weight lowering LDL/HDL ratio lowering blood pressure  Overweight increases blood pressure increases LDL/HDL ratio  Diet high SFA (& to a lesser extent, cholesterol) intake:  LDL/HDL ratio low antioxidant intake favor oxidation of LDL  more sticky high sodium intake can increase blood pressure  Smoking nicotine over-stimulates the heart CO reduces O2 supply to muscles substances in smoke damage walls of arteries &  LDL/HDL ratio increases blood clotting  Age cholesterol plaques build up over decades heart function declines with age  Gender: ♂: higher incidence than ♀, particularly before age 40 estrogens  LDL/HDL ratio  protective effect against atherosclerosis in post-menopausal ♀, LDL/HDL ratio  in the absence of HRT  Hypertension:  risk of vessel damage  sites where fat can deposit  Diabetes: diabetic people have more damaged blood vessels  Psychological: hostile type A individuals have an  risk of heart disease  Heredity 4. Prevention & Treatments Lifestyle changes  Exercise: best are regular aerobic activities (cardiovascular training)  No smoking  Diet - Limitations (/day) cholesterol: max 300 mg total fat intake: max 30% of total energy intake & SFA: max 10% salt - Fruits & vegetables : high amounts are very low in fat (except avocados, rich in MUFAs  OK) include fibers:  blood cholesterol levels include antioxidants: prevent LDL oxidation Medical treatments  Medications - Blood cholesterol lowering drugs - Blood pressure lowering drugs - Blood clotting inhibitors & clot-dissolving drugs  Surgery