CHICAGO – Consider 24-hour ambulatory blood pressure monitoring when patients complain about not getting enough sleep. You might catch hypertension early, according to researchers from the University of Pennsylvania, Philadelphia, and elsewhere.
M. Alexander Otto/MDedge News
Dr. Jordana Cohen
They found a less than 7 hours a night and a mean in the study of 5.5 hours. Every 2-2.5 minutes of lost sleep was associated with an increase of 1 mm Hg in 24-hour mean systolic blood pressure and a increase of 1 beat per minute in heart rate.
The relationship was independent of office BP, nocturnal dipping status, and BP variability. It held in both the obese and nonobese, and in patients with and without obstructive sleep apnea (OSA). However, the relationship was found only among subjects who were not on antihypertensive medications.
“Adults with shorter sleep duration may benefit from screening with 24-hour ambulatory BP monitoring to promote earlier detection of hypertension and potentially mitigate the” the risk of cardiovascular disease. “This may be particularly important in screening for masked hypertension,” meaning normal pressures in the office, but elevated pressures at home, said investigators led by Jordana Cohen, MD, of the department of medicine at the University of Pennsylvania in a presentation at the joint scientific sessions of AHA Council on Hypertension, AHA Council on Kidney in Cardiovascular Disease, and American Society of Hypertension.
Dr. Cohen suggested that perhaps the sympathetic and endothelial derangements that drive hypertension in OSA also affect people with insufficient sleep. It may be that the normal morning surge in blood pressure persists longer into the day, she suggested. The investigative team analyzed data from two studies. The first, LIMBS (Lifestyle Modification in BP Lowering Study), was a phase 2 trial assessing yoga for blood pressure lowering. It was conducted in West Philadelphia and excluded people with diabetes, hypertension, OSA, and kidney or cardiovascular disease. The new analysis included 66 LIMBS subjects who had 24-hour blood pressure monitoring and kept sleep diaries to record their sleep duration (J Clin Hypertens (Greenwich). 2016 Aug;18[8]:809-16).
The team also analyzed 153 subjects from the PISA (Penn Icelandic Sleep Apnea) cohort, an ongoing project assessing continuous positive airway pressure for OSA, among other things. PISA includes patients with OSA, diabetes, hypertension, and kidney or cardiovascular disease. Sleep duration in the 153 subjects was again self-reported, but corroborated by actigraphy (J Sleep Res. 2015 Jun;24[3]:328-38).
The new findings were driven mostly by higher daytime systolic BP among short sleepers in LIMBS, and higher systolic pressures during both day and night among short sleepers in PISA, compared with subjects who slept at least 7 hours, and a mean of 8.5 hours, with napping included in overall sleep duration assessment.
In LIMBS, the mean 24-hour systolic BP was 12.7 mm Hg higher and the average heart rate 8 bpm faster among short sleepers; in PISA, the mean 24-hour systolic BP was 4.7 mm Hg higher and the heart rate 2 bpm faster.
Every 2.57 minutes of sleep lost in LIMBS and every 1.99 minute of lost sleep in PISA was associated with a 1–mm Hg gain in mean systolic BP and about a 1-bpm increase in heart rate. The findings were statistically significant and adjusted for age, race, body mass index, nocturnal dipping status, and office systolic blood pressure.
Baseline characteristics were generally well matched between short and long sleepers in both studies. However, while mean office systolic BP in LIMBS was the same in both sleep groups at about 139 mm Hg, the mean office systolic BP among long sleepers in PISA was 130 mm Hg versus 136 mm Hg among short sleepers, a significant difference.
It’s unclear why some people slept less, Dr. Cohen said, and the use of sleeping pills wasn’t considered in the analysis. Patients were an average of about 50 years old, with a body mass index of about 30 mg/m2. The same model of 24-hour blood pressure monitor was used in both studies.
The work was funded by the National Institutes of Health. The investigators had no disclosures.