Activity-Level Intensity Outshines Volume for Cutting CVD Risk

Posted on 03/12/2022

The study covered in this summary was published on MedRxiv.org as a preprint and has not yet been peer reviewed.

Key Takeaways

Higher daily physical activity levels and intensity of physical activity, both objectively measured, are each associated with reduced risk of new-onset cardiovascular disease (CVD) in both men and women.
Intensity of physical activity seems to show a stronger association with CVD risk.

Why This Matters

Current physical activity recommendations have mainly been based on self-reported measures of exercise. Device-based measures of physical activity may be more accurate.
Few studies have examined the association of device-based measures of physical activity with incident CVD or the interaction between volume and intensity of physical activity.
The new findings support current physical activity recommendations and imply that public health messaging should highlight the need to increase overall volume of activity and, if possible, to incorporate more intense activities.

Study Design

The prospective observational study included 88,412 participants in the UK Biobank registry who agreed to wear a triaxial accelerometer device (AX3, Axivity, UK), which measures changes in movement in three dimensions, for 7 consecutive days.
Participants were recruited from June 2013 through December 2015; those with known history of CVD or who developed new-onset CVD during the first year of wearing were excluded.
Data were obtained in part from a touchscreen questionnaire and biometric assessment at the time of recruitment into the overall UK Biobank study (2006–2010) or from subsequent questionnaires.
Researchers assessed the relationship of new-onset CVD to two key independent variables: (1) average daily physical activity energy expenditure expressed in kJ/kg/d, and (2) proportion of physical activity derived from physical activity of moderate to vigorous intensity.
Covariates for the Cox proportional hazards regression analysis included demographics, lifestyle habits, education, employment, use of blood pressure and cholesterol medicines, insulin prescription or diabetes, history or presence of cancer, mobility limitations, body mass index, parental history of cancer or CVD, the Townsend Index of (material) deprivation, and season of device use.

Key Results

Mean age of participants was 62 years, and 58% were women. The proportion who were considered of normal weight was 40.6%, whereas 40.8% were overweight, and 18.5% were obese.
Participants were followed for a median of 6.8 years.
In the adjusted analysis, the rate of new-onset CVD decreased as average daily physical activity energy expenditure increased.
Increases of 20, 30, 40, and 50 kJ/kg/d, compared with a baseline of 15 kJ/kg/d, were associated with new-onset CVD risk reductions of 16%, 35%, 41%, and 47%, respectively.
Using the same adjustments, as the proportion of physical activity that was of moderate to vigorous intensity went up, the risk of new-onset CVD fell.
Such proportions of 20%, 30%, 40%, and 50%, compared to a baseline of 10%, were associated with risk reductions of 26%, 40%, 48%, and 53%, respectively. The relationship held at any given level of daily physical activity.
At a fixed proportion of activity of moderate to vigorous intensity, however, the risk of new-onset CVD did not fall as daily physical activity energy expenditure grew.

Limitations

The study assessed physical activity at only one time point.
Documentation of demographics, lifestyle factors, comorbidities, and other covariates did not occur during the time of device use.
The UK Biobank population differs in some respects from the overall population, and participants who agreed to using the device may differ from those who did not, potentially creating bias.
Researchers evaluated only absolute intensity of physical activity, whereas intensity relative to a person’s maximal capacity for physical activity may be more important for cardiovascular adaptation.
The authors recommend that their findings be confirmed in other populations with consideration of other biomarkers and disease endpoints (including severity and subtypes of CVD), inclusion of multiple accelerometry studies, and analyses by adiposity level.

Disclosures

Two authors and some of the accelerometer data processing were supported by the Lifestyle Theme of the Leicester National Institute of Health Research (NIHR), Leicester Biomedical Research Center, and NIHR Applied Research Collaborations East Midlands.
Individual authors also acknowledge support from the UK Medical Research Council, the National Health and Medical Research Council of Australia (PCD), and the NIHR Biomedical Research Centre in Cambridge (SB).
The authors declare that they have no competing interests.

This is a summary of a preprint research study, “Association of Physical Activity Volume and Intensity with Incident Cardiovascular Disease: a UK Biobank Study,” written by Paddy Dempsey, PhD, from the University of Leicester and colleagues on MedRxiv.org provided to you by Medscape. This study has not yet been peer reviewed. The full text of the study can be found on MedRxiv.org.

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