A major UK Biobank study suggests that when total activity stays the same, doing a greater share at vigorous intensity is linked to lower risks of heart disease, diabetes, dementia, and other chronic conditions.
Study: Volume vs intensity of physical activity and risk of cardiovascular and non-cardiovascular chronic diseases. Image Credit: muse studio / Shutterstock
In a recent study published in the European Heart Journal, researchers evaluated associations between the proportion of vigorous physical activity (%VPA) and the incidence of chronic disease outcomes.
PA is a modifiable lifestyle factor that can decrease the risk of chronic diseases and mortality. Guidelines recommend 150 to 300 minutes of moderate PA, 75 to 150 minutes of vigorous PA (VPA), or both per week. Studies have found that VPA results in greater improvements in functional capacity, cardiorespiratory fitness, and cardiometabolic risk factors than lower-intensity activities at the same volume.
Moreover, even modest VPA, i.e., 15-20 minutes per week, has been associated with a lower mortality risk. A cohort study also found that a higher %VPA relative to total activity was associated with reduced mortality for the equivalent volume of PA. The PA intensity-benefit relationship has significant implications for public health. However, whether the benefits extend to chronic diseases remains unclear.
UK Biobank Physical Activity Study Design
In the present study, researchers investigated the associations between %VPA and chronic diseases and mortality. They used data from the UKB, a large, prospective cohort study of more than 500,000 people. The International PA Questionnaire (IPAQ) was used between 2006 and 2010 to assess self-reported PA. In addition, a subset of UKB participants wore an accelerometer for seven days from 2013 to 2015, providing device-measured PA data.
The study’s outcomes were eight chronic diseases and all-cause mortality. Chronic disease outcomes were MACE, AFib, T2D, CKD, CRD, dementia, MASLD, and IMIDs. Total PA volume was quantified as metabolic equivalent minutes per week.
In addition, the %VPA relative to total PA volume was estimated. %VPA was categorized into four levels; for accelerometer-based data, the levels were 0%, up to 2%, > 2% to ≤ 4%, and > 4%. For IPAQ-based data, the %VPA levels were 0%, > 0% to ≤ 25%, > 25% to ≤ 50%, and > 50%. Hazard ratios were estimated for incident chronic disease and mortality using Cox proportional hazards models. Model 1 was adjusted for total PA volume, sociodemographic factors, and lifestyle factors.
Model 2 was additionally adjusted for supplement intake, medication use, blood pressure, estimated glomerular filtration rate, body mass index, frailty index score, triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol. Exploratory analyses evaluated dose-response relationships, and population preventable fractions were computed.
Higher %VPA Linked to Lower Disease Risk
Accelerometer-based PA data were available for 96,408 UKB participants aged 61.9 years on average. Among these, there were 9,366 cases of MACE, 4,123 cases of AFib, 2,210 cases of T2D, 942 dementia cases, 2,565 CKD cases, 2,873 cases of CRD, 1,706 MASLD cases, 1,721 cases of IMIDs, and 4,129 deaths during follow-up. IPAQ data were available for 375,730 participants, with an average age of 56.2 years.
Among those with IPAQ data, there were 58,644 MACE cases, 25,103 AFib cases, 13,163 IMID cases, 22,442 T2D cases, 10,747 MASLD cases, 17,061 CKD cases, 20,173 CRD cases, 7,290 dementia cases, and 30,335 deaths. Participants with > 4% VPA had 29% to 61% lower risk of all outcomes than those with 0% VPA in Model 1. In Model 2, the association was attenuated but remained significant.
For instance, the 5-year MACE risk was 10.16% and 6.42% in the 0% VPA and >4% VPA groups, respectively. Similar associations were observed for IPAQ-based %VPA, although effect sizes were smaller, likely reflecting measurement error in self-reported data. A non-linear relationship was observed between %VPA and outcome incidence, with higher %VPA consistently associated with lower risk.
Further, any VPA could potentially prevent 21.4% of CRD, 32.3% of dementia, and 20.3% of IMID cases relative to 0% VPA. IMIDs showed strong dependence on PA intensity, while CKD, MASLD, and T2D showed contributions from both intensity and volume.
Public Health Implications of %VPA
Taken together, higher %VPA levels were associated with lower risks of several chronic diseases and mortality, for a given total PA volume. %VPA showed greater preventive potential than total PA volume across outcomes. These findings support prioritizing higher-intensity activity in public health strategies, while acknowledging that the observational design does not establish causality.