How many hours do you sleep a day? Do you know how many hours you should sleep?

Over time and with the hectic life of modern society, the duration and quality of sleep has significantly decreased, with 46% of Portuguese people sleeping less than 6 hours a day.

An adult between 18 and 65 years old, according to the Portuguese Sleep Association, should sleep between 7 to 9 hours a day, with major consequences when there is a recurrent disrespect for sleep.

It is known today that sleep is as important as food and training, since the lack of sleep is linked to several indicators, such as: reduced appetite control, weight gain, greater difficulty in concentration and productivity, low performance in training, more likely to develop cardiovascular disease and depression, less sensitivity to insulin and even a weaker immune system.



Mulher a acordar | Sono e Controlo do peso | Holmes Place

But how does non-restorative sleep increase appetite and unbalance weight control?

Several studies have shown that people with sleep deprivation see their appetite increased due to the dysregulation of two important hormones: ghrelin and leptin. Ghrelin is a hormone produced in the stomach, which alerts us to hunger; on the other hand, leptin, on the other hand, is a hormone produced by fat cells that suppresses hunger, giving us the feeling of satiety.

A bad night’s sleep increases the hunger hormone (ghrelin) and suppresses the satiety hormone (leptin), which alters the pattern of food intake, with increased appetite during the night, favoring weight gain.

In addition to these two hormones, there is a third that tends to increase with reduced hours of sleep: cortisol. It is known as “stress hormone” and one of the known effects is the induction of appetite.

It is also known that a longer waking time can provide a greater opportunity for food intake, with a great propensity for foods with high energy density. Yes, because even decision-making and self-control are altered by sleep deprivation, making it more difficult to make healthy choices and resist “tempting” foods.


Mulher a comer uma salada | Sono e Controlo do peso | Holmes Place

Lack of sleep can also result in extreme fatigue, which tends to decrease the willingness and motivation to practice physical activity, as well as the intensity, which will naturally be reflected in the reduction of energy expenditure in the inherent physical exercise.

Reducing the basal metabolic rate is yet another potential effect that sleep deprivation causes, causing you to spend fewer calories at rest, not favoring weight control.

Insulin resistance is another decompensation resulting from insufficient hours of sleep. Insulin is the hormone that allows sugar to enter and feed cells. When cells become resistant to insulin, more sugar remains in the bloodstream and the body makes more insulin to compensate. Excess insulin makes us more hungry and induces the body to store excess sugar in the form of fat, promoting weight gain.

So, in addition to eating and training properly, value sleep as a key part in weight control, as well as in your health in general. Start by establishing regular sleep habits and arrange to sleep early.

Do not neglect sleep, respect your body and your health!

Bibliographic references:

1. Cappuccio, F. P., Taggart, F. M., Kandala, N. B., Currie, A., Peile, E., Stranges, S., & Miller, M. A. (2008). Meta-analysis of short sleep duration and obesity in children and adults. Sleep, 31(5), 619–626.

2. Crispim, Cibele Aparecida, Zalcman, Ioná, Dáttilo, Murilo, Padilha, Heloisa Guarita, Tufik, Sérgio, & Mello, Marco Túlio de. (2007). Relação entre sono e obesidade: uma revisão da literatura. Arquivos Brasileiros de Endocrinologia & Metabologia, 51(7), 1041-1049.

3. Romero, Carla Eduarda Machado, & Zanesco, Angelina. (2006). O papel dos hormônios leptina e grelina na gênese da obesidade. Revista de Nutrição, 19(1), 85-91.

4. St-Onge, M. P., McReynolds, A., Trivedi, Z. B., Roberts, A. L., Sy, M., & Hirsch, J. (2012). Sleep restriction leads to increased activation of brain regions sensitive to food stimuli. The American journal of clinical nutrition, 95(4), 818–824.

5. Wu, J. C., Gillin, J. C., Buchsbaum, M. S., Chen, P., Keator, D. B., Khosla Wu, N., Darnall, L. A., Fallon, J. H., & Bunney, W. E. (2006). Frontal lobe metabolic decreases with sleep deprivation not totally reversed by recovery sleep. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 31(12), 2783–2792.

6. St-Onge MP, Roberts AL, Chen J, et al. Short sleep duration increases energy intakes but does not change energy expenditure in normal-weight individuals. Am J Clin Nutr. 2011;94(2):410-416. doi:10.3945/ajcn.111.013904

7. Benedict C, Hallschmid M, Lassen A, et al. Acute sleep deprivation reduces energy expenditure in healthy men. Am J Clin Nutr. 2011;93(6):1229-1236. doi:10.3945/ajcn.110.006460

8. Sebastian M Schmid, Manfred Hallschmid, Kamila Jauch-Chara, Britta Wilms, Christian Benedict, Hendrik Lehnert, Jan Born, Bernd Schultes, Short-term sleep loss decreases physical activity under free-living conditions but does not increase food intake under time-deprived laboratory conditions in healthy men, The American Journal of Clinical Nutrition, Volume 90, Issue 6, December 2009, Pages 1476–1482,

9. Mesarwi, O., Polak, J., Jun, J., & Polotsky, V. Y. (2013). Sleep disorders and the development of insulin resistance and obesity. Endocrinology and metabolism clinics of North America, 42(3), 617–634.

Rita Varela Ramos

Nutricionista Holmes Place do Parque das Nações


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