mental and behavioural changes that follow a 24-hour cycle are referred to as
circadian rhythms. These rhythms, found in mammals including human beings, are
generated in a part of the brain called anterior hypothalamus. They orchestrate
sleep and wakefulness, feeding and energy expenditure, and glucose metabolism.
show that changes in our eating and
sleeping patterns can shift circadian rhythms
. A week of poor sleep can
disrupt our body's intricate physiological timings. One analysis showed that
insufficient sleep alters the expression of about 711 genes in our body.
Melatonin, a hormone that regulates sleep and
wake cycles, is believed to be an important factor that links circadian timing
and insulin production
, lack of which leads
to diabetes. Interestingly, the production
of melatonin is suppressed by light
; it peaks around 3 to 5 hours after
sleep onset. The introduction of artificial light and activity into night-time
hours can thus alter melatonin synthesis. A 2013 study within the Nurses'
Health Study cohort showed that, women with a low production of melatonin are at high risks of developing type-2
. Night-shift workers with irregular and extended working hours
also face similar risks. Whether melatonin supplementation has a role in
treatment of diabetes is still being studied.
Abnormal eating behaviors, particularly
night-time eating, have also shown to contribute to sleep loss leading to
weight gain and obesity.
increases energy expenditure and this is compensated by increased food intake.
People with sleep-loss often resort to after-dinner snacks that are high in
calories (about 42 percent calories more than what they obtain from the smaller
breakfasts that they have). Night-time
eating may alter our circadian rhythm by delaying the onset of melatonin
secretion at night
. Insufficient sleep is also known to disrupt the
signalling of satiety and hunger hormones leading to overeating.
a pandemic, is more rampant in modern times. Life in the modern era of
competition lays unfathomable stress on people, the working class to be more
specific. 'A disrupted sleep schedule,
a physiological drive for more food intake, the availability of high-calorie
foods, and exhaustion leading to less physical activity overall' may all
contribute to weight gain, suggests a recent article in Lancet, a leading medical journal.
Interlinks between sleep and metabolism; Jill Jouret April 2013.