Table 1.

Ongoing sleep extension in free living participants

Study	Design	Participants	Intervention	Sleep	Cardiometabolic Outcome*
Reynold AM, 2014 [71]	Parallel Arm N= 14; 6 control	Adults (6–9 h nightly sleep)	Sleep target: +3 h TIB Control: Habitual sleep Duration: 1 week	Baseline TIB: 7 h 56 min TST: 6 h 47 min Achieved TIB: +2 h 7 min TST: +1 h 59 min	∅ SBP ∅ DBP ∅ Heart rate ∅ TNF-α ∅ Adiponectin ∅ CRP ↑ IL-6
Stock AA, 2020 [72]	Single Arm N=53	College students (6–8 h nightly sleep)	Sleep target: + 1 h TIB Control: Baseline Duration: 1 week	Baseline TIB: 6–8 h TST: 7 h 19 min Achieved TST: + 43 min	↓SBP# ∅ DBP# ∅ Heart rate#
Al Khatib HK, 2018 [73]	Parallel Arm N=42; 21 control	Short sleepers (5–7 h nightly sleep)	Sleep target: +1–1.5 h TIB Control: Habitual Sleep Duration: 4 weeks	Baseline TIB: 7 h 3 min TST: 5 h 28 min Achieved TIB: +55 min TST: +21 min	↓ Free sugar intake ∅ Fasting ghrelin ∅ Fasting leptin ∅ Glucose ∅ Insulin ∅ Blood lipids ∅ BP ∅ Body weight ∅ Body composition ∅ Energy expenditure
Tasali E, 2014 [74]	Single Arm N=10	Adults with overweight BMI and short sleep (< 6.5 h nightly sleep)	Sleep target: 8.5 h TIB via individualized behavioral counseling and sleep hygiene recommendations Control: Baseline Duration: 2 weeks	Baseline TIB:6 h 24 min TST: 5 h 36 min Achieved TIB:+1h48 min TST: +1 hr 36 min	↓ Overall appetite# ↓ Desire for sweet and salty foods# ∅ Desire for fruits, vegetables, and protein- rich food#
Leproult R, 2015 [75]	Single Arm N=16	Adults (≤ 7 h nightly sleep)	Sleep target: +1 h TIB and sleep hygiene recommendations Control: Baseline Duration: 6 weeks	Baseline TST: 5 h 59 min Achieved TST: +44 min	∅ Body weight#∅ Glucose#∅ Insulin#∅ Insulin sensitivity# (Positive associations between TST and glycemic control)
So-Ngern A, 2019 [76]	Cross-Over N=21	Short sleepers (≤ 6 h nightly sleep)	Sleep target: + 1 h TIB and sleep hygiene recommendations Control: Habitual sleep and sleep hygienerecommendations Duration: 2 weeks	Baseline TST: 5 h 18 mins Achieved TST: +36 mins	Intention to Treat ∅ Body weight ∅ Self-selected diet ∅ Glucose ∅ Insulin resistance Per-protocol ↓ Insulin resistance ↑ Early insulin secretion ↑ β-cell function
Haack M, 2013 [77]	Parallel Arm N=22; 9 control	Short sleepers with elevated blood pressure (< 7 h nightly sleep or >1 h less than self-perceived ideal sleep)	Sleep target: +1 h TIB and sleep hygiene recommendations Control: Habitual sleep and sleep hygiene recommendations Duration: 6 weeks	Baseline TST: 6 h 18 mins Achieved TST: +35 mins (+4 min of TST in control)	∅ Body weight ∅ Body composition ∅ Self-selected diet ∅ SBP ∅ DBP ∅ Inflammatory markers
Cizza G, 2014 [79]; Lucassen EA, 2014 [80]	Observational N=125	Short sleepers with obesity (< 6.5 h nightly sleep)	Sleep target: Analysis of participants awaiting randomization into sleep extension or habitual sleep arm Duration: 81 days median observation time	Baseline TST: 5 h 44 min Achieved TST: + 14 min	∅ Body weight#↓ Waist circumference# ↓ Glucose#↓ Insulin#↑ Insulin sensitivity#↓ Total cholesterol#↓ LDL cholesterol#↓ HDL cholesterol#↓ Triglycerides#∅ Fasting ghrelin#
Baron Kelly G, 2019 [81]	Parallel Arm N=16; 5 control	Short sleepers with elevated blood pressure (<7 h nightly sleep)	Sleep target: Up to 8 h TIB or +1 h TIB via technology supported sleep hygiene education and coaching Control: Habitual Sleep Duration: 6 weeks	Baseline TIB: 7 h 2 min TST: 6 h 7 min Achieved TIB: +34 min TST: +34 min	↓ 24-h SBP ↓ 24-h DBP
McGrath ER, 2017 [82]	Parallel Arm N=134; 67 Control)	Impaired sleepers with elevated blood pressure ( >30 min to fall asleep and waking >1 nightly awakening)	Sleep target: Sleep hygiene (education and CBT) and vascular risk education Control: Vascular risk education Duration: 6–8 weeks	Baseline TST: 6 h 56 min Achieved TST: No Change ↑ Sleep Quality	∅ 24-h SBP ∅ 24-h DBP
Sawamoto R, 2016 [89]	Single Arm N=90	Women with elevated BMI (sleep duration eligibility not specified)	Diet & Sleep Target: Diet (−500 kcal/day) and exercise (>8,000 steps/day) lifestyle program with CBT for insomnia Control: Baseline Duration: 7 months	Baseline TST: 5 h 32 min Achieved TST: +14 min (trend)	↓ Body weight#↓ Body fat#↓ Waist circumference# ↓ Hip circumference# ↑ Adiponectin#
Logue EE, 2012 [90]	Parallel Arm N=46;23 control	Adults with elevated BMI (sleep duration eligibility not specified)	Diet & Sleep Target: Diet and exercise CBT via group sessions with sleep education and hygiene recommendations 4 weeks into program. Control: Diet and exercise CBT via group sessions Duration: 12 weeks	Baseline Sleep Efficiency: 85% Achieved Sleep Efficiency: 93% (Change similar to control)	↑ Weight loss
Demos KE, 2015 [91]	Parallel Arm N=25; 13 control	Adults with elevated BMI (≤7 h nightly sleep)	Diet & Sleep Target: 8 h TIB with eating at least every 4 hours across 3–5 meals/day then initiation of energy and dietary fat restricted diet (1,200–1,500 kcal/day) Control: 4 weeks of diet and exercise education then initiation of energy and dietary fat restricted diet (1,200–1,500 kcal/day) Duration: 4 weeks of sleep intervention or general diet education prior to 18 weeks of a weight loss intervention	Baseline TST: 6 h 48 min Achieved TST: ∅ (Objectively TST: +37 min (Self-reported)	↓ Weight loss (6 weeks) ∅ Weight loss (18 weeks)
MorenoFrais C, 2020 [92]	Parallel Arm N=52 (27 control)	Adolescents with obesity (Sleep criteria not specified)	Diet & Sleep Target: +1 h TIB and −500 kcal/day Control: −500 kcal/day Duration: 4 weeks	Baseline TIB: 7 h 48 min TST: 7 h 36 min Achieved TIB: 8 h 54 min TST: 8 h 42 min (+30 min in control group)	Sleep Group: ↓ Body weight#↓ Waist circumference# ↓ Energy intake ∅ Glucose#↓ Insulin#∅ Insulin resistance#∅ HDL cholesterol#∅ Non-HDL cholesterol# ∅ Triglycerides#∅ Leptin#↓ IL=6#∅ TNF-a#∅ Cortisol#Compared to Control: ↓ Body weight ↓ Waist circumference

Hour (h); Minute (min); Time in bed (TIB); Total sleep time (TST); Cognitive behavioral therapy (CBT); Systolic blood pressure (SBP); Diastolic blood pressure (DBP); Not reported (NR); Kilocalorie (kcal)

^*Comparing sleep target to control as defined in intervention column unless otherwise specified by ^#

^#Indicates changes from baseline