Mechanisms Underlying the Blood Pressure Lowering Effect of Sleep

Mechanisms Underlying the Blood Pressure Lowering Effect of Sleep Extension

The main purpose of this study is to learn about the influence of two different behavioral interventions (lasting 8 weeks) involving sleep for lowering blood pressure, and to study the mechanisms involved. There is research evidence that healthy sleep promotes heart-health and may decrease blood pressure, and that sensitivity to insufficient or disrupted sleep may be influenced by sex. This research will compare two interventions that are each designed to improve sleep health, and will investigate sex differences in response. The project includes 3 in-hospital stays with biological measurements to evaluate the underlying mechanisms associated with the effectiveness of two different blood pressure lowering behavioral interventions.

The study involves home-based sleep-wake data collection before and during behavioral intervention, and 3 overnight stays in the hospital. For each hospital stay participants will be asked to arrive in the afternoon, and stay until the next evening. They will be provided dinner on the first day and breakfast, lunch and dinner on the second day. If they are taking any blood pressure medication they will continue to take it through the study. During the in-hospital stays, blood pressure will be measured continuously using two small finger cuffs. In order to monitor and record brain waves to determine sleep and wakefulness, small gold-coated disks called electrodes will be placed on the head and body. Heart rate, blood pressure and brain activity will be recorded for a little over 24 hours on each in-hospital stay. Before as well as during the in-hospital stays questions will be asked about sleep times, subjective sleepiness and other indices relating to well-being.

Inclusion Criteria:

• pre-hypertension or stage one hypertension (BP ≥120/80 and <160/100).
• usual sleep period occurs at night

Exclusion Criteria:

• significant active or uncontrolled sleep disorders
• shiftwork
• current pregnancy
• diabetic patients who are insulin dependent (or have HbA1c>9.0%)
• current use of hypnotics or clonidine
• renal/electrolyte disorders and any other condition that the study screening physician considers would significantly impede participation in the study