In middle-aged adults, higher exercise blood pressures (BPs) and delayed blood pressure recovery after submaximal exercise may be significantly associated with higher risks of hypertension, subclinical and clinical cardiovascular disease (CVD), and all-cause mortality, according to a study published in the Journal of the American Heart Association.
Specifically, researchers found that higher exercise BPs — both systolic and diastolic — were associated with greater risks for hypertension after adjusting for important variables including age, sex, standing pre-exercise systolic and diastolic BPs, resting and peak heart rate, current smoking, BMI, total cholesterol and HDL-cholesterol levels, diabetes, and the use of lipid-lowering agents.
Higher exercise diastolic BP was, in turn, associated with a higher risk of CVD and all-cause mortality. In multivariable-adjusted analyses, both systolic and diastolic BP recovery were inversely associated with the risk of hypertension. Finally, systolic BP recovery was inversely associated with the risk of CVD and all-cause mortality.
“BP responses to exercise are significant markers of CVD and mortality risk in young to middle- aged adults. A number of studies have examined the association between BP responses to exercise in people aged 40 to 55 years and the risk of developing hypertension, stroke, myocardial infarction, CVD, and cardiovascular death. However, limited evidence exists on the associations of exercise BP measures in midlife or later (aged 55 years or older) and risk of outcome events in later life,” wrote these researchers led by Joowon Lee, PhD, of Boston University, Boston, MA.
In this analysis of data from the 1993 Framingham Offspring Study from 1,993 participants (mean age: 58 years; 53.2% women), Lee and colleagues assessed BP response to submaximal exercise and its relation to prevalent subclinical CVD, and the incidence of hypertension, CVD, and all-cause mortality.
At baseline, the prevalence of overweight was 44.2% and of obesity, 24.2%. Subjects had a mean body mass index of 27.4 kg/m2 and a mean total cholesterol of 203 mg/dL. Lipid-lowering mediations were used by 13.9%. In all, 33.6% had hypertension and 23.2% were treated with anti-hypertensive medications. Finally, 6.3% had diabetes and 12.2% were current smokers.
Submaximal exercise was comprised of the Bruce protocol on a treadmill, done in two stages for a total of 6 minutes, with each stage lasting 3 minutes. Exercise BP was recorded halfway through both the first and second stages, and BP recovery after exercise was recorded after each 60 seconds of the 4-minute recovery phase while participants were in a supine position.
During the 12-year follow-up, 44.4% of participants developed new-onset hypertension, 16.2% had an initial CVD event, and 15.1% died.
Upon analysis, Lee and colleagues found that every standard deviation (SD) increment of exercise BP was associated with the following:
- Higher log-transformed left ventricular mass (systolic BP: β=0.02, P ≤ 0.001; diastolic BP: β=0.01, P=0.004).
- Thickness of the carotid intima-media (systolic BP: β=0.08, P ≤ 0.001).
- Higher risk of incident hypertension (systolic BP HR: 1.40; 95% CI: 1.20-1.62; diastolic BP HR: 1.24; 95% CI: 1.11-1.40).
- CVD (diastolic BP HR: 1.15; 95% CI: 1.02-1.30).
In addition, for each SD increment, rapid BP recovery was associated with lower log left ventricular mass (systolic BPrecovery: β=−0.03, P ≤ 0.001) and carotid intima-media thickness (systolic BPrecovery: β=−0.07, P=0.003; diastolic BPrecovery: β=−0.09, P=0.003).
Upon multivariate, adjusted analysis, the hazard ratio for each SD increment of BP recovery was:
- 0.46 for hypertension (systolic BPrecovery 95% CI: 0.38-0.54) and 0.55 (diastolic BPrecovery 95% CI: 0.45-0.67).
- 0.80 for CVD (systolic BPrecovery 95% CI: 0.69-0.93).
- 0.76 for all-cause mortality (systolic BPrecovery 95% CI: 0.65-0.88).
Limitations of the study include that the variability in exercise BP responses was not assessed in relation to risk of outcomes due to lack of data, the inclusion of primarily white participants of European ancestry, and the need to confirm the associations between BP responses to submaximal exercise and the risk of future CVD outcomes in multiethnic cohorts.
“In the current investigation, we observed several important findings. First, exercise BP variables measured in midlife were associated with indicators of subclinical CVD. Additionally, [systolic BP] SBP and [diastolic BP] DBP during submaximal exercise, and SBP and DBP during recovery after submaximal exercise were strongly associated with the risk of developing hypertension after adjustment for potential confounders. Exercise DBP was also positively associated with the risk of CVD. Finally, SBP recovery was inversely associated with the risk of CVD and all- cause mortality in multivariable-adjusted models,” concluded Lee and colleagues.
According to Jim Liu, MD, FACC, of the Ohio State University Wexner Medical Center, Columbus, OH, the study conducted by Lee and fellow researchers was well-designed.
“This was a good-sized trial with nearly 2,000 participants. They also had sound statistical analysis and adjusted for other confounding factors, such as resting blood pressures, smoking status, cholesterol levels, presence of diabetes, body mass index, use of lipid-lowering medications, etc.,” he told BreakingMED.
Further, Liu noted, while these results may not change the way clinicians manage middle-aged patients, they may be useful in assessing CVD risks.
“The article provides an interesting observation, and while it won’t necessarily create any widespread, sweeping changes to current, well-established guidelines on hypertension or cardiovascular disease prevention, it may impact how some clinicians risk stratify patients. This article introduces BP response with submaximal exercise as potentially another useful variable that can help clinicians risk stratify their patients. If a patient was known to have a high BP response with exercise, perhaps that may make the clinician more vigilant in monitoring for cardiovascular disease or more aggressive in instituting lifestyle modification,” he said.
In middle-aged adults, a higher submaximal exercise BP and slower BP recovery after submaximal exercise could portend both clinical and subclinical cardiovascular disease (CVD) and mortality in later life.
Higher systolic and diastolic BPs during submaximal exercise were associated with higher risks for hypertension, as was longer recovery of both systolic and diastolic BPs after exercise.
E.C. Meszaros, Contributing Writer, BreakingMED™
Lee and Liu report no conflicts of interest.
The Framingham Heart Study was supported by the National Heart, Lung, and Blood Institute.
Cat ID: 914
Topic ID: 74,914,730,914,192,48