Maximum Wellness, Episode 121: Midlife Cardiorespiratory Fitness Reduces Risk to Cardiovascular Disease


by Mackie Shilstone.

Researchers from multiple departments of Boston University report in October 2021 in JAMA Network Open that a higher midlife estimated cardiorespiratory fitness level was associated with a lower burden of subclinical atherosclerosis and vascular stiffness, along with a lower risk of hypertension, diabetes, chronic kidney disease, cardiovascular disease, and mortality.

Vascular stiffness refers to left ventricular afterload and the resulting coronary perfusion – leading to cardiovascular disease (CVD). It’s measured by pulse wave velocity (PWV), which can slow with aging – leading to systolic (top blood pressure number) hypertension.

Prior research has shown that a higher CRF level lowers the risk to CVD and all-cause mortality by itself and/or in conjunction with other CVD risk-reduction measures, such as with the Mediterranean eating strategy and weight control.

The American Heart Association recommends that primary care physicians assess CRF in their clinical practices.
As referenced in the Boston University research – Association of Estimated Cardiorespiratory Fitness in Midlife with Cardiometabolic Outcomes and Mortality – “CRF is measured via cardiopulmonary exercise testing; however, this method requires in-person assessment with specialized equipment and trained personnel, rendering it expensive and less accessible.”

Luckily, non-exercise estimated CRF (eCRF) algorithms have been developed using readily available clinical information, such as age, sex, waist circumference, resting heart rate, and physical activity.
In my former hospital-affiliated sports performance, fitness, and wellness programs, we used 12-lead EKG cardiopulmonary VO2 max testing – with a cardiologist interpretation of the data to determine the appropriate heart rate training intensity zones for both athlete and non-athlete.

As for the eCRF, I have successfully used the Polar algorithms and heart rate monitoring devices (polar.com) to provide guidance to members of the US Army Special Operations Command.

To draw their conclusions, the Boston University investigators used data from the Framingham Offspring Study (conducted between 1979 and 2000) in a community-based sample – 2962 participants (52.7 % female) with an average age of 61 – to examine the associations of midlife eCRF, with indices of subclinical atherosclerosis and arterial stiffness, and to incident hypertension, diabetes, chronic kidney disease (CKD), CVD, and mortality in later life.

The participants were assessed using a medical history questionnaire and physical examinations. eCRF was calculated using sex specific algorithms (including age, body mass index, waist circumference, physical activity, resting heart rate, and smoking.

In addition, the investigators assessed carotid-femoral pulse wave velocity (CFPWV), as a measure of arterial stiffness, and coronary artery calcium (CAC) score and carotid intima-media thickness (CIMT), as measures of subclinical atherosclerosis.

The Boston researchers determined that, “midlife eCRF may serve as a marker of cardiometabolic health and mortality in later life, highlighting the importance of adopting a healthy lifestyle, including regular physical activity during midlife.”