Wk 10 and 11 - Physical activity and health and clinical exercise physiology Flashcards
What is physical participation linked to?
- Lower rates of all-cause mortality
- All major forms of CVD
- Improved weight management
- Improved cardiometabolic health
- A lower risk of many major forms of cancer
- Decreased fall risk
- Improved brain and bone health
What is the relationship between moderate to vigorous PA and risk of all cause mortality?
Largest effect with initial increases in MET. No lower threshold for benefit. Pronounced benefits in individuals who did minimal exercise before
What are mortality risk factors?
Obesity, smoker, low CRF, hypertension, high cholesterol and diabetes. Low CRF was linked to mortality and was one of the highest risk factors.
Why is exercise capacity a powerful predictor of mortality?
Found in a study that those who had a lowered MET had a higher risk of mortality, whereas those with high METs had an increased chance of survival.
What are the PA guidelines key recommendations for adults?
- Move more, sit less each day -> Substantial health benefits accrue with weekly activity totals: 150-300 minutes of MVPA and 75-150 minutes of vigorous intensity PA.
- Some activity is beneficial over none at all -> No lower threshold of activity to receive health benefits. Additional health benefits for weekly activity >300 minutes.
- A dose-response relationship exists for most health outcomes -> More activity is generally better
- Moderate to high intensity strength activity should be performed 2 times/ week or more
How to understand the dose-response relationship:
- Potency – relatively unimportant characteristic (does the drug work?)
- Slope – how much change in effect comes from a change in dose
- Maximal effect – efficacy
- Variability – effect varies between and within individuals
- Side effect – adverse effects
What is the dose-response for exercise?
-> Exercise dose adheres to the classic FITT principle:
* Frequency – days per week, times per day
* Intensity - %VO2 max, % maximal HR, RPE and lactate threshold
* Time – number of minutes of exercise
* Type – resistance, CV endurance, swimming, running and rowing
What is the addition of volume and progression to FITT?
-> Volume (frequency x intensity x time) and Progression (transition from easier to harder exercise to gain further improvements and greater benefits)
What is the dose-response for exercise outcome?
the response pattern of physical activity (minutes to weeks) varies depending on the response outcome, includes ->
* Acute response – occur with one or several exercise bouts but do not improve further
* Rapid responses – benefits occur early and plateau
* Linear – gains are made continuously over time
* Delayed – occur only after weeks of training
What are the PA intensity thresholds?
- Physical workloads should be assigned to meet individual abilities, goals, preferences - workloads can be easily assigned in METs and relative VO2 can be estimated from METs
- MET physical activity intensity breakpoints reflect intensity-dependent health gains
- Low intensity PA 1.1. to 2.9 METs
- Moderate intensity PA 3 to 5.9 METs
- Vigorous intensity PA >6METs
- Moderate to vigorous PA is commonly abbreviated MVPA -> MET costs of various exercises, PA, and common activities of daily living are well described and can be prescribed according to reference materials
- PA volume and intensity goals can be achieved through the accumulation of MET-minutes
- Example: 5 METs x 30 min per day x 4 days per week = 600 MET-min (recommended 500 MET-minutes per week)
What is HITT?
HIIT exercise is a time-efficient means of improving cardiorespiratory fitness. Performed by repeated cycles of short duration high intensity exercise and interspersed recovery periods. HIIT is applied to clinical populations but caution is recommended for those with known disease of an accumulation of CVD risk factors. HIIT can be used to see ‘low responders’ and ‘non-responders’ in exercise.
Describe light intensity physical activity (LPA), step counts and health:
- LPA (1.1 to 2.9 METs) is generally not part of a structured exercise prescription programme
- LPA describes activities of the daily living
- Accumulation of LPA is generally associated with improved health outcomes
- LPA can be quantified by step counts
- Step counts are easily monitored with pedometers and modern wearables, including smart watches
- Generalized by step counts e.g. <5000 = sedentary, 5000-7,900 = low active, 7,500-9000 = active and 10,000+ = highly active
What are the general guidelines for improving fitness for healthy and clinical populations?
- Performing MPA reduced health-related problems – risk associated with PA is low
- Risk of cardiac arrest in vigorously active – cardiac event risk is acutely elevated during exercise, however overall cardiac event risk is lower as compared to sedentary
- Risk of deaths is inverse to VO2 max – death risk decreases most when the least fit become active, 1-MET increase is associated with 10-25% improvement in survival
What is the exercise prescription for CRF?
- Dynamic, large muscle activities – walking, jogging, running, swimming, cycling, rowing and dancing
- ACSM recommendation – 3-5 sessions per week, 20-60 min per session, intensity of 40-89% HR range, should result in volume of 500 to 1000 MET-min per week
- Frequency - >5 days per week for MVPA, >3 days per week for VPA, minimum of 2 days per week, gains level off after 3-4 sessions per week, high frequencies associated with increased risk of injury
- Intensity – describes the overload needed to produce a training effect and CRF improvements at 60-80% of VO2 max (lower in those with low initial fitness level – as low as 30% VO2 max). Prescribed using HR target range – linear relationship between HR and VO2.
What are the risk factors for chronic diseases?
-Genetic – age, sex/ gender, race
-Environmental – physical factors, socioeconomic factors and family
-Behavioural (behaviours that increase risk of disease) – smoking, poor dietary habits and physical inactivity
-Physical inactivity is a major risk factors for numerous chronic diseases -> In the US, heart disease (~23%) account for almost half of recorded deaths. 5 of the top 6 leading causes have lifestyle-relates causes, including physical inactivity.
-Web of causation -> Epidemiological model used to establish cause’ of chronic diseases. Difficult to establish the cause of chronic diseases. Example – atherosclerosis – which underpins many of the issues with cardiovascular diseases. Genetic, behavioural and environmental factors interact to cause atherosclerosis.
What are the risk factors for coronary heart disease?
-Associated with atherosclerosis – thickening of the inner lining of arteries. Leading pathological contributor to heart attack and stroke death.
-Associated with risk factors – each risk factor magnifies the risk of CHD. Eliminating a risk factors causes a reduction in risk
-Risk factors include – Age, family history, cigarette smoking, sedentary lifestyle, obesity, hypertension, dyslipidaemia and prediabetes. Can change risk factors, such as reducing amount of cigarettes smoked per day.
What is hypertension?
130mm Hg or >80 mmHg. A major independent risk factor for CHD. A progressive condition, values often increase over time. Diagnoses in young people (20s and 30s) becoming more common. Pharmacologic and lifestyle interventions are affective in treating hypertension. Physical activity is among the most common lifestyle approaches to counter hypertension.
What is post exercise hypotension?
Post exercise hypotension is a common benefit to regular exercise participation. Caused by an extenuation of exercise-induced vasodilation. Physicians should consider a combination of exercise and lower dose hypertensive medications in order to minimise symptoms associated with post exercise hypotension. Can last up to 24-48 hours. Post exercise hypotension is a key mechanism that stimulates the expansion of plasma volume – exercise modality influences this response, but cause similar PV expansion.
Describe PA and hypertension:
Physical activity among the most potent non-pharmacological interventions to treat hypertension. Exercise training can lower resting SBP by an average of 3-10mm Hg and DBP 2-6 mmHg. Clinical relevance – A 2mmHg reduction in systolic blood pressure is associated with reductions of 10% and 7% in the risks of stroke and coronary heart disease, respectively.
Describe obesity risks and PA:
Overweight and obesity are terms that refer to an excess of body fat and they usually relate to increased weight-for-height. The most common method of measuring obesity is the BMI. In the UK, 1 in every 4 adults and around 1 in every 5 children aged 10 to 11 us classified as obese. In the US, 66.3% ate classified as obese or overweight. Obesity increases disease risk for: CHD, stroke, hypertension, type 2 diabetes and cancer. Exercise can promote weight loss. Exercise counters the negative effects of obesity and overweight independent of weight loss.
Describe obesity, inflammation and chronic diseases:
-> Inflammation is the cornerstone for many chronic diseases. In atherosclerosis, chronic inflammation promotes pathological remodelling of the blood vessel walls, resulting in plaque that occludes blood flow. Blood vessel plaques can eventually rupture, resulting in vascular events including heart attacks, strokes and peripheral vascular events.
How does obesity promote inflammation and accelerate the disease process:
- Adipocytes secrete cytokines – adiponectin is anti-inflammatory and IL-6 and TNF-a are inflammatory
- Visceral fat secretes more inflammatory cytokines – interferes with action of insulin (insulin resistance and leads to type 2 diabetes, CVD and metabolic syndrome
Describe blood markers of inflammation:
-Blood markers of inflammation can be predictive of pathological processes that cause chronic diseases -> Low-grade chronic inflammation – high levels of inflammatory cytokines (TNF-a, IL-6, C-reactive protein (CRP))
Describe drugs, diet and PA-impact on chronic inflammation:
Statin drugs (lower LDL-C and CRP can reduce the risk of CV disease and death) and Mediterranean diet (fruits, vegetables and legumes which can reduce CRP and IL-6). Physical activity and/ or fitness – Lower levels of inflammation and IL-6 produced has an anti-inflammatory effect.
