Effects of the Timing of Intense Physical Activity on Hypertension Risk in a General Population: A UK-Biobank Study

It has recently been suggested that the timing of exercise is important in the subsequent development of hypertension. We used the UK Biobank database which prospectively collates data in over 500,000 people aged between 40 and 69 years to determine the relationship between the chronoactivity pattern of exercise and the risk of incident hypertension.

We analyzed data from 70,617 participants with 7-day Axivity AX3 triaxial accelerometry information available. Comparisons were made by a K-means clustering analysis separating groups according to the daily timing of physical activity and intensity. Subgroup, sensitivity analyses, and Cox proportional hazard model were performed. The mean age of the cohort was 61.17 (± 7.89) years with 40.05% men, and there was a mean follow-up of 7.54 (± 1.65) years. Participants were separated into 4 clusters with 6341 developing hypertension. Cluster 1 (early morning physical activity) and Cluster 2 (early morning and later physical activity) had a significantly reduced risk of incident hypertension (adjusted HR 0.870 [95%CI 0.812-0.932) vs. 0.895 [95%CI 0.825-0.972], respectively) when compared with Cluster 3 (physical activity intensity spread evenly throughout the day). Cluster 1 and Cluster 2 cases with High Intensity physical activity had a lower risk of hypertension; however, Low Intensity physical activity in Cluster 1 still reduced the risk of incident hypertension. There was a lower risk of hypertension in Cluster 1 and Cluster 2 in both morning and evening sleep chronotypes. The development of incident hypertension is significantly reduced in those who engage in some level of physical activity earlier in the day. Hypertension (high blood pressure) is a global problem with a high economic health burden that has been shown to be a major risk factor for diabetes, cardiovascular, and kidney disease. Our study has used a large maintained UK biological database to determine the impact of physical exercise on reducing the subsequent development of hypertension during follow-up from data provided by more than 70,000 participants. When we segregated patients into clusters of exercise timing, we found that the risk of developing hypertension over time was reduced for patients who performed exercise earlier in the morning than at other times of the day. This benefit was still evident even when the intensity of regular physical activity was low.