Elsevier

Sleep Medicine

Volume 13, Issue 7, August 2012, Pages 779-786
Sleep Medicine

Review Article
Is shortened sleep duration a risk factor for overweight and obesity during adolescence? A review of the empirical literature

https://doi.org/10.1016/j.sleep.2012.03.016Get rights and content

Abstract

This paper reviews 15 adolescent (10–19 yrs) studies that have directly investigated the effects of shortened sleep duration on overweight and obesity. The research studies included in this review inconsistently found significant effects between shortened sleep duration and weight status. This heterogeneity in study findings largely resulted from variability in study design, gender, and the method used to measure sleep duration. Consequently, due to the conflicting research findings, it remains inconclusive as to whether shortened sleep is a risk factor for overweight or obesity during adolescence. This review also identified methodological limitations within the literature and presented alternative methodologies for future research. First, sleep duration measures were identified that had questionable reliability and were possibly less accurate than other recommended sleep measurements. Second, 92% of cross-sectional studies found a significant relationship, yet 0% of prospective studies did. Third, the vast majority of studies neglected to statistically adjust for co-contributions from depression, and approximately half of the studies considered the role of physical activity. Recommendations for future research directions are presented which may help to clarify the conflicting findings and address the methodological concerns identified within this topical area.

Introduction

This paper aims to review research investigating the effects of shortened sleep duration on overweight and obesity in adolescents. The past few decades have seen an increase in the prevalence of obesity throughout the world [1], [2], [3]. Data from the NHANES between 1966–1970 and 2007–2008 have indicated that obesity rates in 12–17 yr old American adolescents have more than tripled [4]. In 1966–1970 the prevalence of obesity in American adolescents was 4.6%. The prevalence of obesity in American adolescents has since increased to 18.1% in 2007 and 2008. In Australia, comparisons between the Australian Health and Fitness Survey conducted in 1985 and The Australian Nutrition Survey conducted in 1995 found that the prevalence of obesity had tripled in children and adolescents aged between 7 and 15 yrs [5]. Specifically, the prevalence of obesity in Australian boys in 1985 was 1.4% and 1.2% in girls – a decade later the prevalence of obesity was 4.7% for boys and 5.5% for girls.

In response to the obesity crisis, researchers have attempted to identify modifiable factors for potential intervention for this serious public health issue. Many researchers have nominated sleep duration as one such factor, arguing that the shortening of adolescent sleep duration has coincided with the rise of adolescent obesity [6], [7], [8], [9]. However, it should be noted that contradictory epidemiological studies exist which find that adolescent sleep duration has either remained unchanged or increased over time [10].

The theoretical basis proposed to explain a relationship between shortened sleep duration and overweight/obesity are both biological and behavioural. Laboratory studies have found that short-term sleep restriction (typically ⩽4.5 h of sleep) and sleep deprivation can deregulate the appetite controlling hormones leptin and ghrelin [11], [12], [13], [14], [15]. Both leptin and ghrelin have opposing roles in the regulation of appetite and energy homeostasis. Leptin is a hormone secreted from white adipocytes and regulates appetite by suppressing food intake and stimulating energy expenditure [16]. Ghrelin is a hormone secreted from the stomach which regulates appetite by stimulating hunger, fat production, and body growth [16]. These laboratory studies have consistently shown that following total sleep deprivation or restricted sleep, participants have elevated ghrelin or reduced leptin which may predispose weight gain and obesity in the long term [11], [12], [13], [14], [15].

Given the biological explanation provided above, shortened sleep duration could be related to weight status by interacting with behavioural factors such as increased eating. For instance, a recent study found that 16–19 yr old adolescents, who slept <8 h on weekdays, had significantly greater daily consumption of calories consumed from fat than those who slept ⩾8 h during weekdays [9]. This study suggests adolescents with shorter sleep durations have altered eating habits which may predispose obesity. Researchers have also argued that fatigue and daytime sleepiness resulting from sleep deprivation may lead to reductions in daytime physical activity, which could in turn reduce energy expenditure and predispose obesity [17]. However, in Patel and Hu’s [18] review, physical activity did not account for the shortened sleep duration and weight status relationship in any epidemiologic study. Although the biological and behavioural factors described above provide a theoretical framework, this review will focus exclusively on examining the consistency of research findings that have directly assessed the sleep-weight relationship. Although considerable research attention has been given to both adult and child age groups, published reviews have often neglected to separate adolescents from these samples [6], [19], [20].

Adolescence is a dynamic developmental period of physical and sexual development [21] requiring considerable sustenance to fuel such growth and comparable rest periods of sleep. Although significant changes also occur during other developmental periods (i.e., the first two yrs of life [22]), the changes in sleep architecture, sleep homeostasis, and circadian timing during adolescence are also dynamic. Sharp reductions in slow-wave sleep occur [23], which are related to slower rises in sleep pressure in the evening [24]. This may “open the gate” for quiet sedentary activities in the evening, possibly accompanied with snacking [25], [26]. Systemic circadian delays are cited as more common during adolescence [27], thus compounding increases in evening alertness and possibly coinciding with a peak in circadian timing of appetite. With forced morning wakings to attend school, shortened sleep duration then becomes secondary to a delayed circadian shift. These changes in the two main processes of sleep [28] are specific to this developmental period. Thus, a focus on concomitant changes in sleep and weight in the adolescent population is warranted, as conclusions from reviews of the child and adult sleep literature may not generalise to adolescents who experience unique bioregulatory changes.

The primary aim of this review is to determine whether shortened sleep duration is a risk factor for overweight and obesity in adolescents. The review is organised into five sections. First, the study selection criteria are defined. Second, shortened sleep duration is defined for the reader. Third, guidelines for adolescent overweight and obesity are provided to the reader. Fourth, the results of adolescent studies fulfilling the selection criteria are critically evaluated and discussed. Fifth, the review will present specific directions for future research in this area.

Section snippets

Study selection criteria

Consistent with the defined age range for adolescence by the World Health Organisation, this review focussed exclusively on adolescents aged between 10 and 19 yrs. Studies including participants either <10 or ⩾20 yrs were excluded unless their sample had participants in the adolescent age range where separate analyses were performed for this group. Studies were selected using comprehensive searches on (1) electronic databases including: PubMed, MEDLINE, and Google Scholar; (2) electronic journals

Guides for shortened sleep duration, overweight, and obesity

Carskadon et al.’s [23] seminal study demonstrated adolescents consistently obtained 9.25 h sleep across their development when provided with a 10-h sleep opportunity. However, there appears little consensus in the field for the lower limit of adolescent sleep. Research reviewed in this paper has typically (but not without exception) set the sleep duration reference group (normal sleep duration) as being 8 h or greater per night. Thus <8 h sleep is assumed to refer to shortened sleep in adolescent

Summary of research findings in adolescent literature

Table 1 summarises the results of studies investigating the effects of sleep duration on overweight or obesity in adolescents. The results obtained in the adolescent literature have been dependent on: (a) study design, (b) gender, and (c) measures of sleep.

Future directions for research in the area

It is important that the methodological limitations aforementioned in this review are addressed in future research so that a stronger evidence base can be formed, which would provide more definitive knowledge of the unique contribution of sleep duration towards weight changes during adolescence. Specific recommendations for future research include:

  • 1.

    Prospective and experimental study designs using appropriate statistical analyses.

  • 2.

    Research can investigate whether gender interacts with sleep

Conclusion

On the basis of the research reviewed, we unfortunately view the current evidence as providing an inconclusive answer as to whether shortened sleep duration has an effect on adolescent overweight or obesity. A primary reason for making this conclusion relates to the near “bi-model” research findings. When a global measure of sleep duration is used in a cross-sectional manner there is a high chance that a relationship between sleep and weight will be found. However, chances of detecting a

Conflict of Interest

The ICMJE Uniform Disclosure Form for Potential Conflicts of Interest associated with this article can be viewed by clicking on the following link: http://dx.doi.org/10.1016/j.sleep.2012.03.016.

. ICMJE Form for Disclosure of Potential Conflicts of Interest form.

Acknowledgements

The authors wish to thank Dr. Simon Wilksch and Mr. Greg Gardner for their comments on earlier drafts of this review. No financial support was provided for this paper.

References (57)

  • The Australian Institute of Health and Welfare. Risk factor monitoring – a rising epidemic: obesity in Australian...
  • F.P. Cappuccio et al.

    Meta-analysis of short sleep duration and obesity in children and adults

    Sleep

    (2008)
  • N.J. Gupta et al.

    Is obesity associated with poor sleep quality in adolescents?

    Am J Hum Biol

    (2002)
  • A. Weiss et al.

    The association of sleep duration with adolescents’ fat and carbohydrate consumption

    Sleep

    (2010)
  • L. Matricciani et al.

    A review of evidence for the claim that children are sleeping less than in the past

    Sleep

    (2011)
  • J.M. Mullington et al.

    Sleep loss reduces diurnal rhythm amplitude of leptin in healthy men

    J Neuroendocrinol

    (2003)
  • S.M. Schmid et al.

    A single night of sleep deprivation increase ghrelin levels and feelings of hunger in normal-weight healthy men

    J Sleep Res

    (2008)
  • K. Spiegal et al.

    Leptin levels are dependent on sleep duration: relationships with sympathovagal balance, carbohydrate regulation, cortisol, and thyrotropin

    J Clin Endocrinol Metabol

    (2004)
  • K. Spiegal et al.

    Sleep curtailment in healthy young men is associated with decreased leptin levels, elevated ghrelin levels and increased hunger and appetite

    Ann Int Med

    (2004)
  • P. Prinz

    Sleep, appetite, and obesity-what is the link?

    PLos Med

    (2004)
  • S. Taheri

    The link between short sleep duration and obesity: we should recommend more sleep to prevent obesity

    Arch Dis Child

    (2006)
  • S.R. Patel et al.

    Short sleep duration and weight gain: a systematic review

    Obesity

    (2008)
  • P.S. Kaplan

    Adolescence

    (2004)
  • J. Louis et al.

    Sleep ontogenesis revisited: a longitudinal 24-hour home polygraphic study on 15 normal infants during the first two years of lie

    Sleep

    (1997)
  • M.A. Carskadon et al.

    Pubertal changes in daytime sleepiness

    Sleep

    (1980)
  • D.J. Taylor et al.

    Sleep tendency during extended wakefulness: insights into adolescent sleep regulation

    J Sleep Res

    (2005)
  • S.J.H. Biddle et al.

    Temporal and environmental patterns of sedentary and active behaviors during adolescents’ leisure time

    Int J Behav Med

    (2009)
  • O.M. Thompson et al.

    Dietary pattern as a predictor of change in BMI z-score among girls

    Int J Obesity

    (2006)
  • Cited by (76)

    • Associations of sleep duration with childhood obesity: findings from a national cohort study in China

      2022, Global Health Journal
      Citation Excerpt :

      Although unhealthy diet and low exercise are widely accepted as the main behavioral risk factors for obesity and NCDs, other lifestyle factors (such as inadequate sleep) have attracted more and more attention in recent years.4 Previous reviews and meta-analyses have recommended that 8‒9 h of sleep per day is adequate for children, and indicated that short sleep duration was associated with a 45.0% increased risk of developing obesity.5-7 The majority of the studies were from the US and Europe, and may not hold true for Asian and African populations.8

    View all citing articles on Scopus
    View full text