Introducing and maintaining increased cardiorespiratory fitness during early adulthood may reduce the risk of premature death and cardiovascular disease (CVD), findings from the ongoing CARDIA study showed.
Each 1-minute increase in cardiorespiratory fitness (via a maximal graded exercise test) at baseline was associated with a lower risk of all-cause mortality (HR 0.82, 95% CI 0.76-0.88) and fatal or non- fatal CVD events (HR 0.89, 95% CI 0.82-0.96), reported Kelley Pettee Gabriel, PhD, of the University of Alabama at Birmingham, and colleagues.
The effect size was larger for women (HR 0.73, 95% CI 0.64-0.82) than for men (HR 0.87, 95% CI 0.80-0.96).
In addition, each 5% increase in cardiorespiratory fitness maintained over the 20th year of follow-up was associated with a lower risk of all-cause mortality (HR 0.89, 95% CI 0.79-0.99), “with no evidence of effect change by race or sex,” the findings said in JAMA network opened.
“Together, these findings provide new evidence that the transition from early adulthood to midlife is a critical window for optimizing cardiorespiratory fitness to reduce the risk of premature death and non-fatal or fatal cardiovascular disease,” wrote Pettee Gabriel and co. authors.
The research aimed to close a gap in understanding cardiorespiratory fitness and its relationship to aging, the researchers explained.
“In all studies, the timing of cardiorespiratory fitness assessment across the adult life course has varied, with midlife being the most common period, likely due to its proximity to chronic disease outcomes and mortality,” the team wrote. “While this period has led to consistency in findings, it does not determine whether there are critical windows prior to midlife associated with risk of premature death and CVD events.”
In addition, “relying solely on evidence established in middle-aged and older adult populations may lead to erroneous conclusions placing greater emphasis on cardiorespiratory fitness during later life stages simply because cardiorespiratory fitness during earlier life stages was unknown,” the group wrote. “In addition to the premise, the current study also demonstrated the importance of how much cardiorespiratory fitness is maintained in early adulthood through middle age in relation to subsequent risk of premature death.”
Hermes Florez, MD, PhD, of the Medical University of South Carolina and the Ralph H. Johnson Department of Veterans Administration Medical Center in Charleston, and colleagues, wrote in an invited commentary, and colleagues said the results support previous studies showing a reverse association of fitness with all-cause mortality and CVD events, but “adds the value of assessing cardiorespiratory fitness in early adulthood.”
In addition, the commentators said, “the results may provide perspective for studies focusing on cardiorespiratory fitness, CVD and all-cause mortality. The CARDIA study provides evidence that when an individual starts exercising on cardiorespiratory fitness matters and that maintaining higher levels of cardiorespiratory fitness may have a protective association against and reduce the risk of cardiovascular disease.”
Improved cardiorespiratory fitness may also help explain the so-called “fat but fit paradox,” Florez and co-authors added, that the risk of all-cause and cardiovascular disease mortality did not differ between obese and obese subjects. of normal weight if they are both in the top 20% for cardiorespiratory fitness by age and gender.
CARDIA (Coronary Artery Risk Development in Young Adults) is an ongoing prospective cohort study conducted at clinics in Birmingham, Alabama; Chicago, Minneapolis; and Oakland, California. The participants were adults aged 18 to 30 years who completed a maximally graded exercise test at baseline (1985 to 1986) and have had regular follow-up assessments since then. The exercise test was performed at baseline, year 7 and year 20 to assess cardiorespiratory fitness.
The current analysis included 4,808 adults (mean age 24.8, mean body mass index 24.4) who were not taking beta-blockers at the time of exercise testing and who were alive and free of CVD at year 20. A majority (56%) were women, 51% were black and the rest were white. Over the course of 68,751 person-years of follow-up analyzed, 6.3% of participants died and 5.7% experienced a CVD event sometime after the 20-year follow-up assessment.
Study limitations, the researchers said, include the observational nature of the CARDIA study, the specific tests used to determine cardiorespiratory health, and that the specific age range studied could have influenced the findings.
Pettee Gabriel and co-authors reported no conflicts of interest.
Florez and co-authors reported no conflicts of interest.
JAMA network opened
Source reference: Pettee Gabriel K, et al. “Analysis of cardiorespiratory fitness in early adulthood and middle age with all-cause mortality and fatal or non-fatal cardiovascular disease” JAMA Netw Open 2023; DOI: 10.1001/jamanetworkopen.2023.0842.
JAMA network opened
Source reference: Florez H, et al. “Importance of optimizing cardiorespiratory fitness in early adulthood and middle age” JAMA Netw Open 2023; DOI: 10.1001/jamanetworkopen.2023.3637.