Masked hypertension is well known for its poor cardiovascular outcome. But clinical clues related to the masked hypertension and/or masked effect (ME) are rarely known. Physical activity and/or job stress are related to increased daytime blood pressure (BP). This study is to identify whether ME is caused by physical activity and/or job category.

Physical activity using Actical and masked effect by clinic BP and ambulatory BP monitoring were applied to 167 person for this study.

Age of the subjects was 54.9 ± 9.6 and 74 subjects were female (57.4%). Field worker was 81 (48.5%) and office worker was 86 (51.5%). Clinic BP was 125.8 ± 14.3 mmHg / 79.8 ± 10.9 mmHg in male and 119.0 ± 14.0 mmHg / 74.2 ± 8.9 mmHg in female (p = 0.03). Daily energy expenditure representing physical activity was 1,831.1 ± 420.4 kcal. ME for systolic BP was 11.0 ± 11.1 mmHg and ME for diastolic BP was 3.9 ± 8.0 mmHg. In multiple linear regression adjusted by smoking and antihypertensive medication showed that clinic systolic BP was the only significant factor related to the ME (β = -0.44755, p < 0.0001 in male, β = -0.396, p < 0.0001 in female). Physical activity or job category was not related to ME.

Neither physical activity nor job category is related to ME. This indicates that diagnosis of the masked hypertension is not affected by physical activity or job status.