Exercise in Health and Disease SPHK-412 (Exam 2)

What is the equation for oxygen uptake?

VO₂ = Q × (a-v)O₂ difference (Fick equation)

What is the equation for minute ventilation?

VE = tidal volume (mL) × breaths (min^-1)

What does a V/Q ratio < 1.0 indicate?

Good blood flow but inadequate ventilation

What does a V/Q ratio > 1.0 indicate?

Good ventilation but inadequate blood flow

What is the ideal ventilation-perfusion ratio?

About 0.95

What is required to calculate oxygen uptake (VO2)? 

Concentrations of FeO2 and FeCO2 

To calculate energy expenditure, indirect calorimeters use what equation? 

Weir Equation

-Metabolic Rate = [(3.941 x VO2) + (1.11 x VCO2)]  1444

Why is sarcopenia a health risk?

It predisposes to insulin resistance and reduced functional ability

What happens to TEE with age?

Declines, increasing fat mass and sarcopenia risk

What has fat mass (FM)

Non-essential fat, Essential fat.

What has lean body mass (LBM)? 

Skeletal Muscle, Organs, Water. 

What has fat free mass (FFM)? 

-Bones, Skeletal Muscle, Organs, Water 

What is a major modifiable factor for maintaining TEE with age?

Physical activity (NEAT/AEE)

What is sarcopenia?

Age-related muscle wasting, coinciding with a loss in force + power. 

-Decrease in muscle mass, myofiber atrophy, and motor unit function.

What is TEF and what percent of TEE does TEF account for?

The increase in energy expenditure above the basal metabolic rate (BMR) after consuming food. It is the process by which the body digests, absorbs, and metabolizes nutrients. 

-10%

What is AEE/NEAT and what percent of TEE does AEE/NEAT account for?

The amount of energy your body uses for all forms of physical movement, including voluntary exercise and daily activities like fidgeting or maintaining posture. 

-15-30%

What is REE and what percent of TEE does REE account for?

The minimum amount of energy required by the body to maintain essential functions at rest, such as breathing, circulation, and digestion. 

-60-70%

What are the 3 components of total energy expenditure (TEE)?

REE (Resting Energy Expenditure), AEE/NEAT (Activity Energy Expenditure), TEF (Thermic Effect of Food)

What factors influence diffusion according to Fick's Law?

Pressure differential, surface area, diffusion constant, tissue thickness

Which gas diffuses faster—CO₂ or O₂?

CO₂ because it’s more soluble

Oxidative Stress

Imbalance between free radicals and antioxidants.

-Is involved in endothelial disfunction.

Endothelium

Thin layer of cells that lines the inside of blood vessels.

What is postprandial lipemia?

Increase in blood triglycerides and triglyceride-rich lipoproteins (TRLs) after consuming a high-fat meal.

What is the difference between cholesterol and triglycerides?

Cholesterol: Waxy substance vital for cellular membranes, hormones, and production of vitamin D.

-Classified as LDL ( may contribute to plaque build-up) or HDL (exhibit anti-antherogenic properties)

-Produces in the liver and found in animal products.

Triglycerides: Most common fat; stored as unused calories to provide energy.

-Originate from both fat and carbohydrates; excess calories are converted to triglycerides. 

What is LDL cholesterol's effect on arteries?

Contributes to plaque build-up (atherogenesis)

What does HDL do?

-Removes cholesterol from tissues to prevent plaque formation.

-Doesn’t stick to endothelial layer.

What are apolipoproteins?

-Not fats, but proteins that bind to fat.

-Help maintain structural integrity + help regulate fat uptake.

What enzyme does Apolipoprotein C-II activate?

Activates lipoprotein lipase to breakdown triglycerides in lipoproteins.

When does postprandial lipemia peak?

Around 4 hours after eating

What effect does high-fat eating have on endothelium?

Causes transient endothelial dysfunction via oxidative stress

How does acute exercise affect vascular function post-meal?

improves endothelial function, especially when timed 2h post-meal

What is hypertension known as?

The "silent killer"

-Reflects the insidious nature of hypertension which is often undetected for extended periods. 

What are the new AHA hypertension thresholds?

130/80 mmHg (previously 140/90)

What is the normal adult GFR range?

90-120 mL/min

What GFR level indicates chronic kidney disease?

<60 mL/min for 3+ months

Renin

Enzyme produced and secreted by the juxtaglomerular cells. Principle role is to initiate the RAAS system to regulate blood pressure.

Renin Angiotensin Aldosterone System (RAAS) 

A vital complex hormonal system that regulates blood volume, blood pressure, and electrolyte balance in the body, primarily by increasing blood pressure and blood volume in response to low blood pressure or fluid volume

What is angiotensinogen?

Precursor protein produced/released by the liver. Serves as a substrate for renin. Renin cleaves angiotensinogen to produce angiotensinogen I. 

What is angiotensin I?

Biologically inactive form consisting of 10 amino acids. No direct effect on Blood pressure/water retention. Precursor to angiotensin II. 

What is angiotensin II?

Biologically active hormone and primary effector of the RAAS system. Role is to elevate blood pressure and regulate fluid/electrolyte balance.

Vasoconstriction (angiotensin II) 

It constricts blood vessels, increasing systemic vascular resistance and thus elevating blood pressure.

Stimulated aldosterone release (angiotensin II)

Stimulates the adrenal glands to secrete  aldosterone, a hormone that promotes sodium and water reabsorption in the kidneys, increasing blood volume and pressure.

ADH (Vasopressin) secretion (angiotensin II)

Stimulates the release of antidiuretic hormone (ADH), to promote water reabsorption in the kidneys.

Increases sympathetic activity (angiotensin II)

Activates the SNS, which further raises blood pressure through increased heart rate and vascular tone. 

What is aldosteron and its function?

Steroid hormone that primarily increases sodium reabsorption, with water following passively which increases blood volume and pressure.

Electrolyte Balance (Aldosterone)

Aldosteron influences the balance of both sodium and potassium by reabsorbing sodium and excreting potassium. 

Triggers (Aldosterone)

Aldosterone mainly released in response to angiotensin II— activated by low blood pressure or low sodium. 

What is vasopressin and its function?

Hormone that directly increases water reabsorption without sodium involvement which increases blood volume pressure. 

Electrolyte Balance (Vasopressin)

Vasopressin is not (directly) involved in sodium or potassium levels and instead targets water reabsorption. 

Triggers (Vasopressin)

Vasopressin released in response to changes in blood osmolality or low blood pressure/volume. 

What triggers renin release?

Low blood pressure or sodium levels

How does aging affect blood pressure?

Causes vascular remodeling, increasing stiffness and BP

What are the NIH age definitions for mid-life and older adults?

Mid-life: 50-64 years; Older: 65+ years

What happens to muscle and aerobic fitness with age?

both decrease

What happens to oxidative stress and inflammation with age?

both increase

What is the SUPERNOVA phenotype?

individuals with "super-normal" vascular aging—40% lower CVD risk than peers

What are AGEs and what do they do?

Advanced glycation end-products—formed when proteins and lipids between from chronic exposure to sugars. 

List modifiable hypertension risk factors.

Obesity, poor diet (high Na/low K), inactivity, alcohol, tobacco

List non-modifiable hypertension risk factors.

age, sex, genetics

Left Ventricular Hypertrophy 

Left ventricle (main pumping chamber of the heart) becomes thickened and enlarged. 

Define systolic dysfunction.

Myocardium is weak, can’t contract normally and leads to reduced ejection fraction.

Define diastolic dysfunction.

Myocardium is stiff and cannot relax → increased filling resistance

-Ischemic heart disease: Arteries that supply blood to the heart become narrowed and blocked. 

-Chronic Kidney Disease

Factors affecting Excessive Post Oxygen Consumption (EPOC)

Resynthesis of ATP/ PCr/Glycogen

Elevated heart rate/VE/Temperature, thermogenic effect of catecholamines

Metabolic Interia

Finite amount of time needed to activate relavant reducing equivalents. (NADH,FADH2)

Oxygen Limitation 

Conductive and/or diffusive constraints of oxygen delivery to mitochondria for aerobic ATP synthesis. 

What does intensity-dependent increase in? 

Increases in ventilation, cardiac output, and redistribution of blood volume.

What do the medulla/ pons do?

-Govern a normal respiratory cycle.

-Chemical state of blood detected by chemoreceptors. 

-Partial pressure of carbon dioxide (PCO2) in arterial blood is tightly regulated. 

-CO2 is a metabolic by-product of our metabolism, triggers a reflexive rise in ventilation. 

Obesty and Opiates

Can suppress responsiveness to changes in CO2. 

Norepinephrine

Released from postganglionic sympathetic nerve terminals. 

Epinephrine

Releases from the Adrenal Medulla.

Finite amount of blood?

5 Liters

Can cardiac output be increased sufficiently solely by increasing heart rate and contractility? 

No, we are reliant on the skeletal muscle + ventilation pumps for ensuring adequate venous return to overcome orthostatic changes.