TY - JOUR
T1 - Assessing ‘readiness’ by tracking fluctuations in daily sleep duration and their effects on daily mood, motivation, and sleepiness
AU - Ng, Alyssa S.C.
AU - Massar, Stijn A.A.
AU - Bei, Bei
AU - Chee, Michael W.L.
N1 - Funding Information:
We are grateful to Gizem Yilmaz, Shamsul Azrin Jamaluddin, Chua Xin Yu, Pu Zhenghao, Nicole Yu and Nicha Turton for their assistance in data collection. This work was supported by grants from the Yong Loo Lin School of Medicine , Lee Foundation , and the National Medical Research Council Singapore ( STaR May2019 –001 ) awarded to Dr Michael W.L. Chee.
Funding Information:
We are grateful to Gizem Yilmaz, Shamsul Azrin Jamaluddin, Chua Xin Yu, Pu Zhenghao, Nicole Yu and Nicha Turton for their assistance in data collection. This work was supported by grants from the Yong Loo Lin School of Medicine, Lee Foundation, and the National Medical Research Council Singapore (STaRMay2019–001) awarded to Dr Michael W.L. Chee.
Publisher Copyright:
© 2023 The Authors
PY - 2023/12
Y1 - 2023/12
N2 - Study objectives: Consumer sleep trackers issue daily guidance on ‘readiness’ without clear empirical basis. We investigated how self-rated mood, motivation, and sleepiness (MMS) levels are affected by daily fluctuations in sleep duration, timing, and efficiency and overall sleep regularity. We also determined how temporally specific these associations are. Methods: 119 healthy university students (64 female, mean age = 22.54 ± 1.74 years) wore a wearable sleep tracker and undertook twice-daily smartphone-delivered ecological momentary assessment of mood, motivation, and sleepiness at post-wake and pre-bedtime timings for 2–6 weeks. Naps and their duration were reported daily. Nocturnal sleep on 2471 nights were examined using multilevel models to uncover within-subject and between-subject associations between sleep duration, timing, efficiency, and nap duration on following day MMS ratings. Time-lagged analyses examined the temporal specificity of these associations. Linear regression models investigated associations between MMS ratings and sleep variability, controlling for sleep duration. Results: Nocturnal sleep durations were short (6.03 ± 0.71 h), and bedtimes were late (1:42AM ± 1:05). Within-subjects, nocturnal sleep longer than a person's average was associated with better mood, higher motivation, and lower sleepiness after waking. Effects of such longer sleep duration lingered for mood and sleepiness till the pre-bedtime window (all Ps < .005) but did not extend to the next day. Between-subjects, higher intraindividual sleep variability, but not sleep duration, was associated with poorer mood and lower motivation after waking. Longer average sleep duration was associated with less sleepiness after waking and lower motivation pre-bedtime (all Ps < .05). Longer naps reduced post-nap sleepiness and improved mood. Controlling for nocturnal sleep duration, longer naps also associated with lower post-waking sleepiness on the following day. Conclusions: Positive connections between nocturnal sleep and nap duration with MMS are temporally circumscribed, lending credence to the construction of sleep-based, daily ‘readiness’ scores. Higher sleep duration variability lowers an individual's post waking mood and motivation. Clinical trial id: ClinicalTrials.gov NCT04880629.
AB - Study objectives: Consumer sleep trackers issue daily guidance on ‘readiness’ without clear empirical basis. We investigated how self-rated mood, motivation, and sleepiness (MMS) levels are affected by daily fluctuations in sleep duration, timing, and efficiency and overall sleep regularity. We also determined how temporally specific these associations are. Methods: 119 healthy university students (64 female, mean age = 22.54 ± 1.74 years) wore a wearable sleep tracker and undertook twice-daily smartphone-delivered ecological momentary assessment of mood, motivation, and sleepiness at post-wake and pre-bedtime timings for 2–6 weeks. Naps and their duration were reported daily. Nocturnal sleep on 2471 nights were examined using multilevel models to uncover within-subject and between-subject associations between sleep duration, timing, efficiency, and nap duration on following day MMS ratings. Time-lagged analyses examined the temporal specificity of these associations. Linear regression models investigated associations between MMS ratings and sleep variability, controlling for sleep duration. Results: Nocturnal sleep durations were short (6.03 ± 0.71 h), and bedtimes were late (1:42AM ± 1:05). Within-subjects, nocturnal sleep longer than a person's average was associated with better mood, higher motivation, and lower sleepiness after waking. Effects of such longer sleep duration lingered for mood and sleepiness till the pre-bedtime window (all Ps < .005) but did not extend to the next day. Between-subjects, higher intraindividual sleep variability, but not sleep duration, was associated with poorer mood and lower motivation after waking. Longer average sleep duration was associated with less sleepiness after waking and lower motivation pre-bedtime (all Ps < .05). Longer naps reduced post-nap sleepiness and improved mood. Controlling for nocturnal sleep duration, longer naps also associated with lower post-waking sleepiness on the following day. Conclusions: Positive connections between nocturnal sleep and nap duration with MMS are temporally circumscribed, lending credence to the construction of sleep-based, daily ‘readiness’ scores. Higher sleep duration variability lowers an individual's post waking mood and motivation. Clinical trial id: ClinicalTrials.gov NCT04880629.
KW - Ecological momentary assessment
KW - Mood
KW - Motivation
KW - Sleep
KW - Sleepiness
KW - University students
KW - Wearable
UR - http://www.scopus.com/inward/record.url?scp=85173487742&partnerID=8YFLogxK
U2 - 10.1016/j.sleep.2023.09.028
DO - 10.1016/j.sleep.2023.09.028
M3 - Article
C2 - 37804715
AN - SCOPUS:85173487742
SN - 1389-9457
VL - 112
SP - 30
EP - 38
JO - Sleep Medicine
JF - Sleep Medicine
ER -