Jean-Philippe Chaput1, Isabelle J. Dionne2,3
and Angelo Tremblay1,*
1Division of Kinesiology, Department of Social and Preventive
Faculty of Medicine, Laval University, Quebec City, Quebec,
Canada, G1K 7P4.
2Research Centre on Aging, Geriatric
Institute of the University of Sherbrooke,
1036 Belvédère Sud, Sherbrooke, Quebec, Canada,
3Faculty of Physical Education and Sports,
2500 boul. de l'Université,
University of Sherbrooke, Sherbrooke, Quebec, Canada, J1K
Obesity is one of the most important public health problems
today, and although much has been learned regarding the regulation
of body weight, the prevalence of obesity continues to rise.
Excessive caloric consumption and/or lack of physical activity
seem to account only for a fraction of this increase in body
weight. Current treatments for obesity have been largely unsuccessful
in maintaining long-term weight loss, suggesting the need
for new insight into the mechanisms that result into altered
metabolism and behavior and may lead to obesity. Parallel
to an increase in body weight, there has been a reduction
in sleep times (1). Indeed, lack of sleep has become a widespread
habit driven by the demands and opportunities of our modern
"24-hour" turbulent lifestyle. Nearly one-third
of adults report sleeping less than 6 hours per night, leading
some to suggest that we live in a sleep-deprived society (2).
Not surprisingly, reports of fatigue and tiredness are more
frequent today than a few decades ago (3).
Cross-sectional (4-6) and longitudinal (7,8) studies in adults
have repeatedly found an association between reduced sleep
and increased weight. Similar findings have been observed
in children, suggesting that short sleep duration correlates
with an increased risk of being overweight or obese (9-11).
Furthermore, recent research data from our laboratory showed
that the increase in body weight associated with short sleep
duration is preferentially deposited in the abdominal region
(12). Since there is an increased recognition that abdominal
obesity is the most prevalent feature of the metabolic syndrome,
i.e. a cluster of diabetogenic, atherogenic, prothrombotic
and proinflammatory metabolic abnormalities (13), these results
add novel insights to the negative impact of short sleep duration
Of course, the obvious question is: "How short sleep
duration is related to obesity?" Ultimately, in order
to cause weight gain, short sleeping hours must increase caloric
intake and/or decrease energy expenditure. In this respect,
one potential explanation may be that when we sleep less,
we simply have more time and/or more opportunities to eat.
In addition, restricted sleep may lead to daytime fatigue
and perhaps reduced physical activity. However, much attention
has recently been focused on the responses of ghrelin, leptin
and orexin to sleep restriction (4,14,15). Alterations in
these hormone levels or patterns of secretion may affect hunger
and appetite, increasing the risk of overeating and consequently
weight gain. They may also affect thermogenesis from activities
other than exercise. Non-exercise thermogenesis (such as seen
in fidgeting and posture changes) is a variable component
of energy expenditure and has been reported to account for
differential weight gain in rats (16). In addition, sleep
loss results in changes in levels of several other hormones
such as cortisol and growth hormone (17). However, the precise
mechanisms by which the brain modulates hormone release with
sleep loss is unknown, but one possibility is increased sympathetic
nervous system activity (18,19).
Thus, short sleep duration may be perceived as a stress factor
having a destabilizing impact on body homeostasis. In this
regard, lack of sleep is related to a greater risk of being
overweight probably because it prevents the recovery of a
hormonal profile facilitating appetite control. In this context,
fat gain contributes to at least a partial compensation since
adipose tissue hypertrophy favors an increase in plasma leptin
Does short sleep duration favor overweight or obesity
in older people?
Although a growing body of evidence supports an association
between short sleep duration and the risk for obesity, the
literature is nonexistent regarding the documentation of this
issue in older people. In a 13-year prospective study conducted
in almost 5,000 young adults, Hasler et al. (7) showed that
the associations between sleep duration and obesity diminished
after age 34 years, albeit the age of participants did not
exceed 40 years. However, we recently published results showing
that short sleep duration does not predict an increased risk
of being overweight or obese in older women (20). To our knowledge,
it is the first study showing data about the sleep-body weight
connection in the elderly. We were surprised by the results
of our study since they are not concordant with the relevant
literature in this field of investigation. Although it is
difficult to explain the absence of relationship between sleep
and body composition in older people as observed in younger
age groups, some arguments might be considered. Indeed, it
is possible to argue that the decrease in the sensitivity
to leptin and ghrelin with age (21,22) might explain in part
the observed discrepancy. Moreover, recent data indicate that
anorexigenic signals (e.g., leptin) prevail over orexigenic
signals (e.g., ghrelin) in healthy elderly, contributing to
prolonged satiety and inhibition of hunger, which may lead
to calorie deficit (22). Nevertheless, further studies are
highly needed in order to confirm these results and to further
investigate the sleep?body fat associations in older people.
Our modern world, with its hectic lifestyle, has favored the
dominance of factors promoting positive energy balance in
which short sleep duration is potentially associated with
alterations in the hormonal profile that impair the regulation
of energy balance. Given the compelling body of work supporting
the associations between short sleep duration and obesity
in children and adults, sleep time must now be considered
as a new and potentially important determinant of obesity
in the current way of living. Since preventing obesity is
important, a pragmatic approach adding sleep hygiene advice
to encouragement towards a healthy diet and physical activity
may help tackle the obesity pandemic. However, there is an
urgent need for studies aiming to investigate the sleep-body
weight connection in the elderly. By doing so, this will help
unravel this issue in this population and to establish its
1. National Sleep Foundation. 2006
"Sleep in America" Poll. Washington, DC: National
Sleep Foundation, 2006.
2. Bonnet MH, Arand DL. We are chronically sleep deprived.
Sleep 1995; 18: 908-911.
3. Bliwise DL. Historical change in the report of daytime
fatigue. Sleep 1996; 19: 462-464.
4. Taheri S, Lin L, Austin D, Young T, Mignot E. Short sleep
duration is associated with reduced leptin, elevated ghrelin,
and increased body mass index. PLoS Med 2004; 1: 210-217.
5. Gangwisch JE, Malaspina D, Boden-Albala B, Heymsfield SB.
Inadequate sleep as a risk factor for obesity: analyses of
the NHANES I. Sleep 2005; 28: 1289-1296.
6. Chaput JP, Després JP, Bouchard C, Tremblay A. Short
sleep duration is associated with reduced leptin levels and
increased adiposity: results from the Quebec Family Study.
Obesity 2007; 15: 253-261.
7. Hasler G, Buysse DJ, Klaghofer R et al. The association
between short sleep duration and obesity in young adults:
a 13-year prospective study. Sleep 2004; 27: 661-666.
8. Patel SR, Malhotra A, White DP, Gottlieb DJ, Hu FB. Association
between reduced sleep and weight gain in women. Am J Epidemiol
2006; 164: 947-954.
9. Chaput JP, Brunet M, Tremblay A. Relationship between short
sleeping hours and childhood overweight/obesity: results from
the "Québec en Forme" Project. Int J Obes
2006; 30: 1080-1085.
10. Sekine M, Yamagami T, Handa K et al. A dose-response relationship
between short sleeping hours and childhood obesity: results
of the Toyama Birth Cohort Study. Child Care Health Dev 2002;
11. von Kries R, Toschke AM, Wurmser H, Sauerwald T, Koletzko
B. Reduced risk for overweight and obesity in 5- and 6-y-old
children by duration of sleep-a cross-sectional study. Int
J Obes 2002; 26: 710-716.
12. Chaput JP, Tremblay A. Does short sleep duration favor
abdominal adiposity in children? Int J Pediatr Obes 2007 (in
13. Després JP, Lemieux I. Abdominal obesity and metabolic
syndrome. Nature 2006; 444: 881-887.
14. Spiegel K, Tasali E, Penev P, Van Cauter E. Brief communication:
sleep curtailment in healthy young men is associated with
decreased leptin levels, elevated ghrelin levels, and increased
hunger and appetite. Ann Intern Med 2004; 141: 846-850.
15. Sakurai T. Roles of orexins and orexin receptors in central
regulation of feeding behavior and energy homeostasis. CNS
Neurol Disord Drug Targets 2006; 5: 313-325.
16. Novak CM, Kotz CM, Levine JA. Central orexin sensitivity,
physical activity, and obesity in diet-induced obese and diet-resistant
rats. Am J Physiol 2006; 290: 396-403.
17. Spiegel K, Leproult R, Van Cauter E. Impact of sleep debt
on metabolic and endocrine function. Lancet 1999; 354: 1435-1439.
18. Spiegel K, Leproult R, L'hermite-Baleriaux M, Copinschi
G, Penev PD, Van Cauter E. Leptin levels are dependent on
sleep duration: relationships with sympathovagal balance,
carbohydrate regulation, cortisol, and thyrotropin. J Clin
Endocrinol Metab 2004; 89: 5762-5771.
19. Spiegel K, Knutson K, Leproult R, Tasali E, Van Cauter
E. Sleep loss: a novel risk factor for insulin resistance
and Type 2 diabetes. J Appl Physiol 2005; 99: 2008-2019.
20. Chaput JP, Lord C, Aubertin-Leheudre M, Dionne IJ, Khalil
A, TreA. Is overweight/obesity associated with short sleep
duration in older women? Aging Clin Exp Res 2007; 19: 290-294.
21. Wang ZW, Pan WT, Lee Y, Kakuma T, Zhou YT, Unger RH. The
role of leptin resistance in the lipid abnormalities of aging.
FASEB J 2001; 15: 108-14.
22. Di Francesco V, Zamboni M, Zoico E et al. Unbalanced serum
leptin and ghrelin dynamics prolong postprandial satiety and
inhibit hunger in healthy elderly: another reason for the
"anorexia of aging". Am J Clin Nutr 2006; 83: 1149-52.
1,* Address for correspondence: Angelo Tremblay, Ph.D.
Division of Kinesiology (PEPS)
Quebec City, Quebec, Canada
Tel: (418) 656-7294
Fax: (418) 656-3044
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