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Cardiovascular disease (CVD) is a leading cause of death globally, and hypertension, also known as high blood pressure, is a major risk factor for CVD. According to the Centers for Disease Control and Prevention (CDC), approximately 108 million adults in the United States have high blood pressure. The prevalence of hypertension increases with age, and it is estimated that nearly two-thirds of adults aged 60 years and older have hypertension.
What is high BP?
Blood pressure (BP) is the force of blood against the walls of the arteries. It is measured in millimeters of mercury (mmHg) and consists of two numbers: systolic BP and diastolic BP. Systolic BP is the pressure when the heart beats, and diastolic BP is the pressure when the heart rests between beats. High systolic BP, also known as systolic hypertension, is defined as systolic BP of 130 mmHg or higher. High systolic BP is a major risk factor for CVD, especially in older adults.
What is cardiorespiratory fitness?
Cardiorespiratory fitness (CRF) refers to the ability of the cardiovascular and respiratory systems to supply oxygen to the muscles during physical activity. It is measured by the maximum amount of oxygen that the body can consume per minute per kilogram of body weight (VO2max). The higher the VO2max, the higher the CRF. CRF can be improved through regular physical activity, such as aerobic exercise.
Physical fitness, specifically cardiorespiratory fitness, is known to be an important predictor of mortality and morbidity, independent of other risk factors for CVD, including hypertension. Cardiorespiratory fitness refers to the ability of the circulatory and respiratory systems to supply oxygen to the muscles during physical activity.
A recent study published in the Journal of the American College of Cardiology sought to investigate the relationship between cardiorespiratory fitness, hypertension, and CVD mortality in middle-aged and older men. The study included over 4,200 men aged 50 to 75 years who underwent a treadmill exercise test to measure cardiorespiratory fitness and were followed for an average of 10 years.
The researchers found that higher levels of cardiorespiratory fitness were associated with a lower risk of CVD mortality, regardless of the presence of hypertension. Interestingly, the protective effect of cardiorespiratory fitness was more pronounced in men with high systolic blood pressure (SBP) levels. Systolic blood pressure is the top number in a blood pressure reading, and a high SBP is considered to be 130 mmHg or higher.
Specifically, the researchers found that men with high SBP levels who had high levels of cardiorespiratory fitness had a 44% lower risk of CVD mortality compared to men with high SBP levels who had low levels of cardiorespiratory fitness. In contrast, men with normal SBP levels who had high levels of cardiorespiratory fitness had a 33% lower risk of CVD mortality compared to men with normal SBP levels who had low levels of cardiorespiratory fitness.
These findings have significant implications for public health, particularly in the context of the aging population. The study suggests that improving cardiorespiratory fitness may be an effective strategy for reducing the risk of CVD mortality, even in individuals with hypertension. Additionally, the study highlights the importance of maintaining a physically active lifestyle in middle-aged and older adults, particularly in those with high SBP levels.
However, it is important to note that this study was limited to middle-aged and older men and may not be generalizable to women or younger individuals. Additionally, the study was observational and cannot establish causality. Nevertheless, the study provides strong evidence for the importance of cardiorespiratory fitness in reducing the risk of CVD mortality in men with hypertension.
In conclusion, the findings of this study underscore the importance of physical fitness in reducing the risk of CVD mortality, particularly in individuals with hypertension. Maintaining a physically active lifestyle, including regular exercise, may be an effective strategy for reducing the risk of CVD mortality, even in individuals with high blood pressure. Future research is needed to investigate the relationship between cardiorespiratory fitness and CVD mortality in other populations, including women and younger individuals.