Week 10 Flashcards
(23 cards)
Relationship Between Physical Activity and Mortality?
Studies show a significant inverse relationship between fitness levels and mortality rates:
Higher fitness levels = Lower mortality rates.
The largest effects are observed with initial increases in MET (Metabolic Equivalent of Task) levels.
For example, individuals with higher fitness may have mortality rates as low as 18.6 per 10,000 person-years, compared to 64.0 per 10,000 person-years in those with lower fitness.
Mortality risk factors?
Obesity
Smoking
Low Cardiorespiratory fitness
Hypertension
High cholesterol
Diabetes
Highest risk of mortality is low CRF
Physical Activity Guidelines for Adults?
- Adults should aim for:
- 150-300 minutes of moderate-intensity aerobic physical activity per week, or
- 75-150 minutes of vigorous-intensity activity per week
- Additional benefits arise from exceeding these guidelines.
- Muscle-strengthening activities are recommended at least 2 times per week.
What is exercise prescription and what are its key components?
Exercise prescription is similar to a medical prescription, based on dose-response principles to achieve specific health or performance outcomes.
Key Parameters (FITT):
Frequency (F): Number of exercise sessions per week
Intensity (I): Effort level, often measured by %VO₂ max or perceived exertion
Time (T): Duration of each exercise session
Type (T): Mode of activity (e.g., running, cycling, swimming)
Extended Model – FITT-VP: Added for comprehensive training
Volume (V): Total exercise load = Frequency × Intensity × Time
Progression (P): Gradual increase in workload to improve fitness and gain further benefits
What are exercise dose-response relationships? Concepts? Types?
Exercise dose-response relationships help determine how much exercise (dose) is needed to achieve a specific benefit (response).
Key Concepts:
Potency: How little exercise is needed to elicit a response (less important clinically—does it work?)
Slope: How much the response changes with increasing exercise dose
Maximal Effect: The greatest benefit achievable (efficacy)
Variability: Responses vary between and within individuals
Side Effects: Potential adverse effects (e.g., injury, overtraining)
Types of Responses to Exercise:
Acute: Immediate response after a single session
Rapid: Benefits appear quickly but plateau (e.g., blood pressure reduction)
Linear: Steady improvements over time with consistent training
Delayed: Results that emerge after weeks or months (e.g., increased VO₂ max)
Physical Activity Intensity Thresholds?
- Physical workloads should be assigned to meet individuals abilities, goals and preferences.
- Physical workloads are often measured in METs:
- Low-intensity: 1.1 - 2.9 METs
- Moderate-intensity: 3.0 - 5.9 METs
- Vigorous-intensity: ≥6 METs
- Recommended weekly MET-minutes: 500-1000 for substantial health benefits.
Eg 5 Mets x 30 mins per day x 4 days per week = 600 Met-Min
High-Intensity Interval Training (HIIT)?
- HIIT involves short bursts of intense activity followed by rest or low-intensity exercise.
- Provides time-efficient cardiovascular benefits.
- Studies show HIIT can double cardiorespiratory fitness gains compared to moderate-intensity training.
- Caution advised for individuals with high CVD risk.
Light Intensity Physical Activity (LPA) and Step Counts?
- LPA includes daily activities (e.g., walking) and contributes to overall health.
- Step count classifications:
- Sedentary: < 5,000 steps/day
- Low active: 5,000 - 7,900 steps/day
- Active: 7,500 - 9,000 steps/day
- Highly active: ≥10,000 steps/day
Exercise Guidelines for Different Populations?
- Moderate physical activity is generally safe with low adverse event risk.
- Clinical populations may require personalized exercise prescriptions.
- Cardiorespiratory fitness (CRF) improvements are more pronounced in low-fit individuals.
3 Major risk factor categories?
Genetic: Age, Sex/gender, race, susceptibility to disease.
Environmental: Physical factors (eg air water noise etc), socioeconomic factors(education, income), family (divorce, death of loved ones etc)
Behavioural: Smoking, poor diet, physical inactivity, overuse of meds.
What is the Web of Causation in epidemiology?
A model used to explain the complex, multi-factorial causes of chronic diseases.
Shows how genetic, environmental, and behavioral factors interact to contribute to disease development.
Example: Atherosclerosis—influenced by multiple interrelated risk factors (e.g. diet, genetics, lifestyle).
Makes it hard to pinpoint a single cause, as many factors contribute simultaneously or indirectly.
What is Coronary Heart Disease (CHD)? Risk factors?
Associated with atherosclerosis which is the thickening of inner lining of arteries which is leading contribution to heart attacks or stroke death.
Each risk factors magnifies CHD eliminating a risk factor causes reduced chance of CHD.
Risk factors include:
Age, Family History, Cig smoking, Sedentary lifestyle, Obesity, Hypertension, Dyslipidemia, Prediabetes
Hypertension?Prevalence? Effects of Activity?
- Defined as systolic BP >130 mmHg or diastolic BP >80 mmHg.
- Major independent risk factor for coronary heart disease (CHD).
Prevalence:
- Progressive condition; blood pressure often increases over time.
- Increasingly common in young adults (20–30 years).
Physical activity is the most effective lifestyle intervention:
- Regular training can lower resting systolic BP by 3–10 mmHg and diastolic BP by 2–6 mmHg.
- Even a 2 mmHg drop in systolic BP is linked to a 10% reduction in stroke risk and 7% reduction in CHD risk.
Obesity and Physical activity? Prevalance? health risks? Role of PA?
Overweight/obesity Refers to excess body fat, usually related to increased weight for height. Measured by Body Mass Index (BMI scale)
Prevalence:
- UK: 1 in 4 adults, 1 in 5 children are obese
- UK adults: 63% overweight or obese
- US adults: 66.3% overweight or obese
Health Risks of Obesity:
- Coronary Heart Disease (CHD)
- Stroke
- Hypertension
- Type 2 Diabetes
- Cancer
Role of Physical Activity:
- Activities like walking, running, swimming, tennis can help with weight loss
- Requires 2.5–3 hrs/week of moderate-to-vigorous activity
- Exercise alone may not be enough—must be combined with a caloric deficit or controlled diet
- High volume/intensity may be challenging for overweight individuals
Hypotension?
Post exercise hypotension is a common benefit from regular exercise.
Is a key mechanism in stimulating expansion if plasma volume.
Caused by extenuating of exercise induced vasodilation
Physicians often pair/combine exercise with lower dose of hypertensive meds to initiate post exercise hypotension symptoms.
Inflammation and diseases?
Inflammation is a key driver of many chronic diseases:
Atherosclerosis:
- Chronic inflammation remodels blood vessels
- Leads to plaque buildup → potential rupture → heart attacks, strokes, vascular disease
Obesity-related inflammation:
- Adipose tissue (especially visceral fat) secretes cytokines
— Pro-inflammatory: IL-6, TNF-α
— Anti-inflammatory: Adiponectin - Promotes insulin resistance → increases risk of Type 2 diabetes, CVD, metabolic syndrome
Inflammatory biomarkers:
- Chronic low-grade inflammation shown by elevated TNF-α, IL-6, CRP
- Predictive of long-term disease risk
Drugs, diet and Exercise effects on Inflammation?
Statin drugs.
• Lower LDL-C and CRP.
• Can reduce risk of cardiovascular disease and death.
Mediterranean diet.
• Fruits, vegetables, legumes, whole grains, olive oil.
• Reductions in CRP and IL-6.
Physical activity and/or fitness.
• Lower levels of inflammation.
• IL-6 produced has an anti-inflammatory effect. (Good and bad, depends how it enters system)
Definition of the Metabolic Syndrome? How is it acquired?
• Metabolic syndrome is the medical term for a combination of diabetes, high blood pressure
(hypertension) and obesity. It is a cluster of risk factors that promote the development of coronary heart
disease, stroke and other conditions that affect blood vessels (e.g. PAD).
An individual that has three or more of the following risk factors is considered to have the metabolic syndrome:
1. Abdominal obesity (e.g., Waist circumference >102 cm (men) and >88 cm (women).
2. Hypertriglyceridemia (triglyceride levels in the blood of ≥1.7 mmol/L (fasted) (≥150 mg/dl))
3. Low HDL cholesterol (men: <1mmol/L (40 mg/dl); women: <1.2 mmol/L (<50 mg/dl)).
4. High blood pressure (140/90 mm Hg or higher).
5. Inability to control blood sugar levels (insulin resistance; fasting blood glucose >5.6 mmol/L (100 mg/dl))
Prevalence
- Affects an estimated 1 in 3 older adults aged 50 or over in the UK.
- Similar in US (37% across all adults), but worrying signs in recent data
What Causes the Metabolic Syndrome? Prevention ?
Two major competing hypotheses - not mutually exclusive.
1. Low grade chronic inflammation.
• Increased levels of TNF-a, IL-6, CRP cause insulin resistance.
• Leads to obesity and type 2 diabetes.
2. Increased oxidative stress.
• Increased production of free radicals cause cellular damage
and inflammation.
Guidance on Physical activity to prevent and treat, it is recommended to:
i. Reduce sedentary time
ii. Moderate intensity exercise daily for a
minimum of 30 but preferably 60 minutes
Asthma? Causes?
A respiratory problem characterized by breathlessness, chest tightness, and a wheezing sound.
An estimated 300 million people worldwide suffer from asthma (WHO, 2015)
Has Early and Late phase.
Asthma cause by:
• Contraction of smooth muscle of airways.
• Swelling of mucosal cells.
• Hypersecretion of mucus.
Common asthma triggers include:
• house dust mites
• animal fur
• pollen
• cigarette smoke
• viral infections
• Exercise (can also induce asthma - EIA)
Exercise-induced asthma (EIA)?
Caused by respiratory tract cooling and drying.
• Increases osmolarity on surface of mast cell
• Triggers release of chemical mediators and airway narrowing
More prominent in some sports than others (e.g., aerobic exercise).
More common in asthmatics.
Does not necessarily impair performance if the condition is medically controlled.
• Diagnosed by exercise challenge.
• Strenuous running/cycling at 85 to 90% of max HR.
• ≥10% decrease in FEV1 indicates E I A.
Prevention and treatment of E I A
To reduce the chances of an E I A attack:
• Warm up.
• Perform short-duration exercise.
• Use scarf or face mask in cold weather.
Pharmacologic treatments include:
• Beta-agonist in case of attack during exercise.
Chronic obstructive pulmonary disease (COPD)
COPD is the term given to a group of lung diseases:
- Chronic bronchitis, Emphysema, and Bronchial Asthma
• Can create irreversible changes in the lung.
• Can severely limit normal activities (creates a cycle of patient inactivity)
• Physical activity level shown to be the strongest predictor of all-cause mortality in
patients with COPD (Waschki et al. 2011)
Testing for COPD.
• FEV1 (forced expiratory volume in one second)
• Graded exercise test.
• VO2 max.
• Maximal exercise ventilation.
• Changes in arterial PO2 and PCO2.
Treatment of COPD
Goals:
i. Reduced reliance on O2 and medications
ii. Improved ability to complete daily activities, increase exercise tolerance, lower BP etc
iii. Increased sense of well-being, QoL, reduce breathlessness anxiety and social isolation
Interventions:
i. Breathing exercises:
- Does not reverse the disease, but improves respiratory muscle strength and endurance
ii. Exercise training
- Does not reverse the disease, but can improve exercise tolerance and limits dyspnea
- HIIT maybe better than continuous training, may permit higher intensities
- Warm up and cool down very important (10-15 min)
