Fitness, Fatness, and Systolic Blood Pressure
Fitness, Fatness, and Systolic Blood Pressure
Background Modifying risk factors to delay or prevent hypertension is critical for subsequent cardiovascular risk reduction. Therefore, understanding the independent and joint associations between cardiorespiratory fitness, obesity, and systolic blood pressure (SBP) is of major significance. In this study, we assessed the relative contribution of body mass index (BMI) and cardiorespiratory fitness to SBP in a large, healthy population.
Methods Blood pressure, BMI, and cardiorespiratory fitness were measured in 35,061 patients seen for a preventive health examination (1990 to present). BMI was treated as a continuous variable and categorized into sex-specific quartiles. Cardiorespiratory fitness was defined as time achieved during maximal exercise testing and categorized into age- and sex-adjusted quintiles. Generalized linear models were used to determine the independent contribution of fitness and BMI on systolic blood pressure estimates.
Results The study group was predominately white men (69%) with an average age of 46 years. Normal-weight subjects had a mean SBP 12 mm Hg lower than in the obese (115 vs 127 mm Hg, P < .001), while being high- fit was associated 6 mm Hg difference in mean SBP comparing the highest and lowest fitness quintile (119 vs 125 mm Hg, P < .001). Normal-weight individuals with a cardiorespiratory fitness level greater than the first quintile (Q1) had the lowest mean SBP (P < .001). Both BMI and cardiorespiratory fitness were associated with SBP (P < .001 for both); however, when assessed simultaneously, BMI had a greater impact on SBP estimates than fitness.
Conclusion When comparing lifestyle risk factors BMI and cardiorespiratory fitness, BMI was a more important factor in predicting SBP. Importantly, only modest fitness levels among normal-weight individuals were associated with the lowest systolic blood pressure estimates.
Cardiorespiratory fitness, defined as maximal achieved exercise capacity on treadmill or bicycle ergometer, is a strong and independent predictor of cardiovascular disease mortality. The mechanism by which cardiorespiratory fitness confers protection has not been fully elucidated but has been hypothesized, in part, to be due to reductions in blood pressure. Epidemiological studies have shown that exercise and improved cardiorespiratory fitness are associated with lower hypertension risk independent of other risk factors. Intervention studies have confirmed these observational data, demonstrating absolute reductions in systolic blood pressure of 3 to 4 mm Hg achieved with exercise training.
In addition to cardiorespiratory fitness, other lifestyle factors are associated with hypertension, most notably obesity. However, few studies have studied the relative impact of body mass index (BMI) and cardiorespiratory fitness on systolic blood pressure. A key unanswered question is whether hypertension prevention should be focused on weight control by any acceptable intervention, or whether cardiorespiratory fitness, independent of BMI, is a more important first target for prevention of hypertension. This has significant implications for health-care providers and patients in creating the most effective first strategies to achieve optimal blood pressure control.
To this end, we assess the relative impact of BMI and cardiorespiratory fitness on systolic blood pressure among >35,000 predominately white men and women in the Cooper Center Longitudinal Study, a population well phenotyped for BMI, cardiorespiratory fitness, and systolic blood pressure.
Abstract and Introduction
Abstract
Background Modifying risk factors to delay or prevent hypertension is critical for subsequent cardiovascular risk reduction. Therefore, understanding the independent and joint associations between cardiorespiratory fitness, obesity, and systolic blood pressure (SBP) is of major significance. In this study, we assessed the relative contribution of body mass index (BMI) and cardiorespiratory fitness to SBP in a large, healthy population.
Methods Blood pressure, BMI, and cardiorespiratory fitness were measured in 35,061 patients seen for a preventive health examination (1990 to present). BMI was treated as a continuous variable and categorized into sex-specific quartiles. Cardiorespiratory fitness was defined as time achieved during maximal exercise testing and categorized into age- and sex-adjusted quintiles. Generalized linear models were used to determine the independent contribution of fitness and BMI on systolic blood pressure estimates.
Results The study group was predominately white men (69%) with an average age of 46 years. Normal-weight subjects had a mean SBP 12 mm Hg lower than in the obese (115 vs 127 mm Hg, P < .001), while being high- fit was associated 6 mm Hg difference in mean SBP comparing the highest and lowest fitness quintile (119 vs 125 mm Hg, P < .001). Normal-weight individuals with a cardiorespiratory fitness level greater than the first quintile (Q1) had the lowest mean SBP (P < .001). Both BMI and cardiorespiratory fitness were associated with SBP (P < .001 for both); however, when assessed simultaneously, BMI had a greater impact on SBP estimates than fitness.
Conclusion When comparing lifestyle risk factors BMI and cardiorespiratory fitness, BMI was a more important factor in predicting SBP. Importantly, only modest fitness levels among normal-weight individuals were associated with the lowest systolic blood pressure estimates.
Introduction
Cardiorespiratory fitness, defined as maximal achieved exercise capacity on treadmill or bicycle ergometer, is a strong and independent predictor of cardiovascular disease mortality. The mechanism by which cardiorespiratory fitness confers protection has not been fully elucidated but has been hypothesized, in part, to be due to reductions in blood pressure. Epidemiological studies have shown that exercise and improved cardiorespiratory fitness are associated with lower hypertension risk independent of other risk factors. Intervention studies have confirmed these observational data, demonstrating absolute reductions in systolic blood pressure of 3 to 4 mm Hg achieved with exercise training.
In addition to cardiorespiratory fitness, other lifestyle factors are associated with hypertension, most notably obesity. However, few studies have studied the relative impact of body mass index (BMI) and cardiorespiratory fitness on systolic blood pressure. A key unanswered question is whether hypertension prevention should be focused on weight control by any acceptable intervention, or whether cardiorespiratory fitness, independent of BMI, is a more important first target for prevention of hypertension. This has significant implications for health-care providers and patients in creating the most effective first strategies to achieve optimal blood pressure control.
To this end, we assess the relative impact of BMI and cardiorespiratory fitness on systolic blood pressure among >35,000 predominately white men and women in the Cooper Center Longitudinal Study, a population well phenotyped for BMI, cardiorespiratory fitness, and systolic blood pressure.
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