The study looked at the sleep patterns of more than 12,000 people for nine months, focusing on the irregular patterns of what time they went to bed, how much time they slept, and what time they woke up in the morning. Most of the people studied were middle-aged men who were overweight. If their wakeup time varied by 43 minutes, they had an almost 9% increased risk for high blood pressure.
Inconsistent sleep times also make a difference, regardless of how long people sleep. The study noted that getting varying hours of sleep each night can increase your risk for high blood pressure by as much as 17%. For example, getting six hours of sleep a few days a week and nine hours on others can affect your blood pressure.
Staying up late a few nights a week also stresses your arteries. If the time you go to bed varies by 34 minutes, that raises your high blood pressure risk by 32%. Variations in the midpoint time of your sleep are also linked to an 18% increased risk for high blood pressure.