Habitual short sleep duration (\< 7 hours/night) increases the risk of cardiovascular disease (CVD) and all-cause mortality. Yet most adults, especially emerging adults (i.e., 18-25 years) do not achieve the National Sleep Foundation recommendation of 7-9 hours of sleep each night. Additionally, the American Heart Association recently included sleep duration in the "Life's Essential 8". This recent development emphasizes the importance of sleep and the need to advance our understanding of how sleep impacts cardiometabolic health (CMH), particularly in emerging adults, a population whose CVD risk trajectory is malleable. Specifically, emerging adulthood is a critical age window when age-related loss of CMH accelerates. Based on my previous work and others, both self-reported and objective measures of poor sleep (e.g., duration, variability) are linked to early signs of elevated CVD risk in emerging adults, such as microvascular dysfunction and elevated central blood pressure (BP), which precede the development of hypertension.
The investigators aim to address the knowledge gap on whether sleep extension is a viable strategy to improve CMH in emerging adults with habitual short sleep duration. A prior study demonstrated the feasibility of sleep extension to improve BP and perceived sleepiness in predominantly normotensive emerging adults (18-23 years). Even without hypertension, reductions in BP are generally beneficial for CMH. The research hypothesis is that sleep extension (one extra hour in bed per night) will improve CMH and health behaviors in emerging adults who self-report \< 7 hours of sleep per night. The primary aim is to determine if sleep extension is effective in improving BP. Investigators will assess CMH after habitual sleep (2 weeks) followed by a 2-week sleep extension intervention in 60 emerging adults (\~30 female).
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
60
Participants will extend their time in bed by one hour for 2 weeks while being monitored.
Auburn University
Auburn, Alabama, United States
Blood pressure reactivity
The investigators will measure blood pressure using photoplethysmography at the finger during rest and handgrip exercise.
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Passive Leg movement
Passive leg movement will be used assessed blood flow responses to movement. The investigators will usie continuous measures of femoral artery diameter and velocity via duplex Doppler ultrasound (Hitachi Arietta 70) to calculate blood flow at rest and with the passive lelg movement. The femoral artery will be imaged in the longitudinal plane distal to the inguinal crease using a high-frequency (10-12 MHz) linear-array probe. Participants will be in a seated, reclined position with the lower leg free hanging. The ultrasound probe will be positioned by a lab member and the image will be recorded throughout triplicate 60-s measurements. Another lab member will independently move the lower leg through 90º range of motion at a rate of 1 Hz.
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Circulating intercellular adhesion molecule 1 (ICAM-1)
Researchers will assess circulating markers intercellular adhesion molecule 1 (ICAM-1) using ELISA; samples will be run in triplicate and with quality controls.
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Circulating Vascular adhesion molecule 1 (VCAM-1)
VCAM-1 will be assessed using ELISA ; samples will be run in triplicate and with quality controls
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Objective sleep duration
Philips actiwatch spectrum will be used to quantify sleep duration. Participants will wear the watch units for 14 days. The investigators will assess sleep duration and cross-check actigraphy wear times with a sleep diary.
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Objective sleep efficiency
Philips actiwatch spectrum will be used to quantify % of time in bed actually spent sleeping to calculate sleep efficiency.
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Subjective sleep duration
The investigators will use the Pittsburgh Sleep Quality Index to asses sleep duration reflective of the one month period leading into the study.
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Subjective sleep quality
The investigators will use the Pittsburgh Sleep Quality Index to assess perceived sleep quality reflective of the one month period leading into the study. The global score scale is 0 to 21.
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Subjective Sleepiness
The investigators will administer the Epworth Sleepiness Scale (ESS). The scale is scored as 0-10 (normal sleepiness), 11- 14 (mild sleepiness), 15-17 (moderate sleepiness), and 18 -24 (severe sleepiness).
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Pulse wave analysis
The investigators will use the SphygmoCor XCEL system to assess pulse wave analysis (PWA) The sampling site is the brachial artery (upper alarm instrumented with a cuff for oscillometric sphygmomanometer). PWA will be expressed as % (calculated as augmentation pressure divided by the pulse pressure).
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Pulse wave velocity
The investigators will use the SphygmoCor XCEL system to assess pulse wave velocity (PWV) The sampling site is the carotid artery (tonometry) and femoral artery (upper leg instrumented with a cuff for oscillometric sphygmomanometer). PWW will be expressed as meters per second.
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Cognitive motor task
The investigators will use a dual task assessment that involves walking an responding to prompts.
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Circulating Leptin
Blood sample will be analyses with an enzyme-linked immunosorbent assay (ELISA) kit.
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Circulating Ghrelin
Blood sample will be analysed with an enzyme-linked immunosorbent assay (ELISA) kit.
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Cardiorespiratory fitness
The investigators will use indirect calorimetry to measure the participant's maximal oxygen consumption (VO2max) during incremental exercise on a treadmill. The investigators will use a Parvo TrueOne metabolic cart and Woodway treadmill.
Time frame: Pre- intervention
Mental health - social anxiety
The investigators will administer the Liebowitz Social Anxiety Scale. The scale starts at 0 (none) and ends at 3 (severe) for 24 questions related to anxiety and avoidance, and a cumulative score is calculated.
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Appetite Assessment
Appetite assessment via a visual analog scale (0 not feeling hungry/thirsty to 150 hungry/thirsty) and an ad libitum breakfast to measure food intake will take place during each of the experimental visits.
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Hematocrit
Blood samples will be analyzed for hematocrit content (Thermo Hematocrit Microcentrifuge).
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Hemoglobin
Blood samples will be analyzed for hemoglobin content (HemoCue, radiometer)
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Urine Osmolarity
Researchers will analyze 24-hour urine samples for osmolarity (AI Osmometer 3D3)
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Urine Electrolytes
Researchers will analyze 24-hour urine samples for electrolyte (Na, K, Cl) content using the SmartLyte Electrolyte Analyzer. The Na, K, Cl will be expressed as milliequivalents (mEq).
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Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Blood Glucose
Researchers will analyze blood for glucose concentrations using the Cholestech.
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Blood Cholesterol
Researchers will analyze blood for cholesterol (total, LDL and HDL) using the Cholestech.
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Circulating Insulin
Blood sample will be analyses with an enzyme-linked immunosorbent assay (ELISA) kit.
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)
Oxidized LDL
Blood sample will be analyses with an enzyme-linked immunosorbent assay (ELISA) kit.
Time frame: Change score from habitual sleep to day 15 (after 14 days of sleep extension)