10.01 Why Exercise Flashcards
Why is exercise often described as a physical integration of the response to stress?
Because it is an expenditure of calories that leads to an increased heart rate, increased metabolic demand and challenge to homeostatic mechanisms both cardiovascular, respiratory and metabolic
Describe the ecological model of the determinants of physical activity
The levels include INDIVIDUAL (psychological factors, biological factors like genetics), INTERPERSONAL (w/ group training and social support and cultural norms highly influential), ENVIRONMENTAL like more parks, less buildings and social environment. REGIONAL and NATIONAL POLICY like transport systems, elevators, education and GLOBAL like media, economic development etc.
What is the general trend seen in many research articles between levels of activity and cardiovascular events?
With more levels of physical activity, there is a cardiovascular protective effect (also in all cause mortality)
Relate age related declines to physical inactivity
Age related declines have some association w/ physical inactivity and not to ageing itself (like skeletal muscle sarcopenia and reduced energy levels to do physical activity and co-morbidities associated with age)
What is a MET?
Called the METABOLIC EQUIVALENT: The ratio of the work metabolic rate to the resting metabolic rate.
ie. 1 MET is the resting metabolic rate and is roughly equivalent to the energy cost of sitting quietly (1 kcal/kg/hour)
What is the relationship between increased exercise capacity and mortality?
The larger the METs of individuals, the greater their survival curves across many causes of mortality (including Hypertension, COPD, Diabetes, Smoking, Obesity, Hypercholesterolaemia)
Is level the benefit of exercise directly correlated with the intensity of the activity?
Studies show that with more vigorous the exercise, there isn’t much health benefit c.f. moderate exercise intensity. There seems to be a plateauing of the protective health benefits w/ level of MET
What have the trends been in relation to occupation related physical activity?
There has been a large increase in light MET and sharp decline in Moderate MET (with increases in sedentary LOW MET) leading to overall decrease in protective effects and increase in physical inactivity due to the nature of work and urbanisation and technological advances.
Comparison of Leisurely Active vs. Inactive people (who work in the same office) showed that the time spent inactive counteracts the activity such that both groups were almost at the same level.
Large bouts of INACTIVITY is a problem as well (not just lack of exercise)
What are the biological consequences of physical inactivity?
Increasing abdominal adiposity causing increased macrophage infiltration leading to chronic low grade systemic inflammation leading to the health risks like atherosclerosis, insulin resistance, tumor growth and neuroegeneration
What are some pathways that have been looked at as potential “pills” for exercise
AMPK and PPARdelta agonists are being looked at as exercise mimetics as they have been seen to be activated in exercise leading to the peforance imporvements, adaptations to muscle and the multiorgan systemic effects.
BUT they have major side effects and are nowhere near reaching the benefit of exercise itself (more realistic to use as an adjunct to exercise)
How does Exercise exert its protective effects?
We don’t really know
What is the relationship of exercise to risk of diabetes?
It is significantly reduced by exercise (even more than seen with metformin/pharmacological intervention)
Describe the benefit of exercise compared to the benefit of their pharmacological/surgical counterpart interventions
Exercise shows to have a HIGHER BENEFIT for cardiac disease, angina, type II diabetes, breast cancer than their medial interventions.
It has an equivalent effect for major depression
