Objectives: 
Stress, and particularly job strain, has been found to associate with ambulatory blood pressure (BP). Moreover, BP is known to vary between days. One potential over-looked factor underlying this day-to-day BP variation could be work-related psychosocial factors. Thus, we aimed to study the association between job strain, job demands, job control and day-to-day BP variation.

Methods: 
The home BP of 754 regularly working participants (mean age 50.9 ± 4.8, women 51%) of the Finn-Home Study was measured twice in the morning and twice in the evening over seven days. Average SBP and DBP were calculated for each day. Work-related psychosocial factors were measured with survey. Multivariable-adjusted generalized linear models were used for statistical analysis.

Results: 
We found a greater SBP/DBP decrease between weekdays and weekend among participants with high job strain (-1.8 [95% confidence interval, 95% CI, -2.7 to -0.8]/-1.7 [95% CI, -2.3 to -1.1] mmHg) compared to participants with low job strain (-0.7 [95% CI, -1.1 to -0.2]/-0.7 [95% CI, -1.0 to -0.4] mmHg). The participants with high job demands showed a higher BP decrease between weekdays and weekend (-1.4 [95% CI, -2.0 to -0.8]/-1.3 [95% CI, -1.6 to -0.9] mmHg) than the participants with low job demands (-0.5 [95% CI, -1.1 to 0.0]/-0.6 [95% CI, -1.0 to -0.3] mmHg). We did not find BP differences regarding job control.

Conclusion: 
High job strain and high job demands were associated with a greater BP reduction from weekdays to the weekend. Work-related psychosocial factors should be considered when assessing day-to-day BP variation.