High blood pressure and low fitness levels were each associated with an increased risk of CVD mortality independently of established and emerging risk factors in new findings.
High cardiorespiratory fitness levels may attenuate, but not eliminate, the increased risk of death from cardiovascular disease (CVD) in men with elevated systolic blood pressure, according to new research.1
Investigators from the University of Eastern Finland suggested high blood pressure and low fitness levels, in turn, are each associated with an increased risk of CVD mortality independent of established and emerging risk factors.
“This was the first study to evaluate the joint effects of fitness and blood pressure on the risk of dying from cardiovascular disease,” said Jari Laukkanen, MD, PhD, Institute of Public Health and Clinical Nutrition, University of Eastern Finland.2 “The results suggest that being fit helps protect against some of the negative effects of high blood pressure.”
Over 1 billion adults over the age of 30 globally have hypertension, a major risk factor for CVD and stroke, as well as a leading cause of premature death. Cardiorespiratory fitness, a measure of aerobic exercise capacity, is a strong predictor of all-cause and CVD mortality. It has been shown to modify the association between adverse levels of risk factors and adverse outcomes, with higher fitness levels linked to reduced risks of adverse outcomes.
To better understand this association, Laukkanen and colleagues examined the interplay between blood pressure, fitness, and CVD mortality risk in a prospective cohort of 2280 middle-aged and older men enrolled in the Kuopio Ischemic Heart Disease (KIHD) Risk Factor Study. The screening and baseline assessments were conducted between March 1984 and December 1989, including blood pressure and cardiorespiratory fitness.
Investigators assessed fitness as peak oxygen uptake (VO2peak) while riding a stationary bicycle. Study participants were grouped according to blood pressure level and fitness level: normal blood pressure–high fitness (reference comparison); normal blood pressure–low fitness; high blood pressure–high fitness; and high blood pressure–low fitness. Data showed the average age of participants at baseline was 53 years, mean blood pressure was 134 mmHg, and fitness level was 30.3 mL/kg/min, respectively.
Of the 2280 men followed up for a median duration of 29 years, there were 644 deaths due to CVD, according to investigators. Risk of death from CVD was analyzed after adjustments for age, body mass index (BMI), smoking status, type 2 diabetes (T2D), coronary heart disease, antihypertensive medication-use, alcohol consumption, physical activity, socioeconomic status, and high sensitivity C-reactive protein.
Upon analysis, results indicated high blood pressure was associated with a 39% increased risk of cardiovascular mortality (hazard ratio [HR], 1.39; 95% confidence interval [CI], 1.17 – 1.63). When considering fitness levels, compared with high levels, low fitness was associated with a 74% increased risk of CVD mortality (HR, 1.74; 95% CI, 1.35 – 2.23).
Individuals with high blood pressure and low fitness had more than double the risk of CVD mortality compared to those with normal blood pressure and high fitness levels (HR, 2.35; 95% CI, 1.81 – 3.04). When men with high blood pressure had high fitness levels, the data showed their elevated risk of CVD mortality persisted, but was weaker, being only 55% higher than those with normal levels in each category (HR, 1.55; 95% CI, 1.16 - 2.07).
Laukannen and colleagues noted the inability of higher fitness levels to fully eliminate the risk of CVD mortality in individuals with high blood pressure may have to do with the strong, independent causal relationship between blood pressure and CVD.
“Getting blood pressure under control should remain a goal in those with elevated levels,” Laukannen said.2 “Our study indicates that men with high blood pressure should also aim to improve their fitness levels with regular physical activity. In addition to habitual exercise, avoiding excess body weight may enhance fitness.”