How might regular cardiorespiratory exercise affect hypertension?
Regular physical activity has been shown to affect cardiovascular risk factors, including hypertension significantly. The mechanisms underlying these effects are the subject of ongoing investigations. Still, regular exercise reduces blood pressure via alterations in cardiac output, stroke volume, and arterial compliance.
Cardiorespiratory fitness rather than physical activity per se appears to be the critical factor in reducing hypertension, with higher levels of fitness being associated with more significant improvements.
How might regular cardiorespiratory exercise affect diabetes mellitus?
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Fitness levels may have an essential role in reducing blood glucose concentrations in Type 2 diabetes mellitus by overcoming insulin resistance. Higher volumes of physical activity are associated with lower risks of developing diabetes.
Still, even small amounts can benefit many risk factors for cardiovascular disease and metabolic disorders. Improvements occur not only at the whole-body level but also within individual tissues, including skeletal muscle, where increased oxidative capacity enhances glucose uptake.
Regular physical activity has improved glycemic control over time, although results are variable since some individuals appear more resistant to the effects than others.
How might regular cardiorespiratory exercise affect obesity?
It is now recognized that adipose tissue plays an essential role in determining whole-body insulin sensitivity and glucose metabolism. Adiponectin, a protein secreted by fat cells, increases insulin sensitivity, whereas interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and retinol-binding protein 4 (RBP4), all secreted by adipocytes, decrease insulin sensitivity.
The secretion of these factors can be influenced by fitness level and body mass. A high volume of physical activity appears to increase IL-6 and adiponectin concentrations decrease TNF-alpha and RBP4 concentrations.
The combined effect of increased insulin sensitivity and reduced levels of other adipokines may assist in reducing obesity, but further research is required to determine the ideal volume and type of exercise necessary.
How might regular cardiorespiratory exercise affect non-alcoholic fatty liver disease?
Non-alcoholic fatty liver disease (NAFLD) encompasses a range of conditions, including simple hepatic steatosis and steatohepatitis, which can progress to cirrhosis and cancer. Studies have shown that increased fitness reduces NAFLD incidence, particularly among diabetes mellitus, but the mechanisms are not fully understood.
One hypothesis suggests that exercise improves glycaemic control, thereby preventing triglyceride accumulation and inflammation.
How might regular cardiorespiratory exercise affect cancer?
Aerobic capacity is inversely associated with cancer, with increased peak oxygen uptake (VO2peak) associated with longer survival rates. This may partly explain how physical activity reduces the risk of cardiovascular disease and diabetes mellitus since such conditions are also linked to reduced life expectancy.
Evidence shows increased fitness increases mitochondrial biogenesis within cells, enhancing their bioenergetic potential and reducing oxidative stress. However, there is no conclusive evidence that exercise alters cancer incidence directly, nor whether different types of exercise have varying effects on cellular processes that can lead to tumor formation or progression.
How does cardiorespiratory exercise affect hypertension??
It was believed that only severe hypertension could be affected by increased fitness for many years since mild to moderate elevations in blood pressure is often associated with other lifestyle factors.
Aerobic exercise has been shown to lower resting and stress-induced blood pressures while increasing coronary perfusion. However, whether this directly affects improved fitness or secondary to the impact on body weight and adipokines remains unclear.
However, there is emerging evidence that even low volumes of physical activity can reduce ambulatory blood pressure at rest, suggesting that cardiorespiratory fitness may have an essential role in lowering high blood pressure risk even before the overt disease appears.
How does cardiorespiratory exercise affect cognitive function?
Cognitive function and cardiac rehabilitation are relatively new, but research has shown associations between fitness levels and cognitive function. High-fit individuals have been found to perform better on standardized tasks involving working memory, executive function, and visuospatial ability compared to low-fit individuals.
Whether aerobic exercise can prevent the decline in cognition associated with normal aging is not yet clear, but there is some evidence from animal models that it may be beneficial. Collectively these studies suggest that regular cardiorespiratory activity may benefit several disease processes through its effects on adipokines and bioenergetic capacity.
However, further research is necessary to determine the ideal volume and type of exercise required for optimal benefits across multiple health outcomes.
The most important take-home messages from this:
Health benefits of physical activity contribute to extended life expectancy and lower risk of cardiovascular disease, Type 2 diabetes mellitus, and some cancers.
Regular cardiorespiratory exercise can reduce inflammation, improve glycaemic control and enhance mitochondrial bioenergetic potential, which independently may reduce the risk of non-alcoholic fatty liver disease (NAFLD), cancer, hypertension, and cognitive decline.
Further research is required to establish whether different types of exercise have varying effects on cellular processes that lead to tumor formation or progression. Since most studies involve relatively well individuals, it is essential to determine whether the relationship between fitness/physical activity levels and health outcomes in diseased individuals differs from their healthy counterparts.
Studies suggest that even low volumes of physical activity can lower blood pressure, and evidence suggests it can reduce ambulatory blood pressure at rest. Whether this directly affects improved fitness/cardiorespiratory or secondary to other beneficial effects such as reducing weight and adipokines remains unclear.