Efecto de la privación de sueño sobre la variabilidad de la frecuencia cardíaca / Effect of sleep deprivation on heart rate variability

La privación de sueño es una entidad muy frecuente y con diversos efectos a nivel de losprocesos cognitivos y fisiológicos. A su vez, constituye tanto un problema médico como social por las consecuencias de sus efectos. Durante el sueño se distinguen dos estados comportamentales: el sueño no-REM (NREM) y REM. Durante el sueño NREM hay una escasa actividad cognitiva y un adecuado control homeostático de las funciones fisiológicas. Durante el sueño REM, existe un estado cognitivo particular, los sueños, asociado a una disminución del control de algunas variables fisiológicas como la temperatura, la frecuencia cardíaca y respiratoria. La variabilidad de la frecuencia cardíaca (VFC) medida a partir del electrocardiograma (ECG), constituye un correlato de su regulación autonómica. Con el objetivo de evaluar el impacto de la privación aguda de sueño sobre la VFC, se realizaron registros polisomnográficos y electrocardiográficos basales utilizando al gato como modelo animal, durante la privación de sueño y el período post-privación. Para ello se instrumentaron dos estrategias de privación de sueño: privación total de sueño y privación selectiva de sueño REM. Se analizaron diversos parámetros de la VFC en los estados de vigilia (W), sueño NREM y REM. En el dominio del tiempo se evaluó: intervalo RR promedio, desvío estándar de los intervalos RR normales ("standard deviation of normal R-R intervals" SDNN), el cual refleja todos los componentes cíclicos de la variabilidad, y rMSSD ("root mean squared difference of successive intervals") que permite estimar variaciones a corto plazo de la frecuencia. En el dominio de la frecuencia (obtenidas mediante la transformada rápida de Fourier) se evaluó: potencia de las bandas "Low Frequency" (LF), considerada tanto un marcador de la modulación simpática como un parámetro que incluye influencias vagales como simpáticas, y "High Frequency" (HF), determinada principalmente por la actividad vagal sobre el corazón, la frecuencia del "pico" o punto máximo de dichas bandas. También se estudió la relación LF/HF, relacionada con la modulación simpática. A su vez, se analizó la dinámica no-lineal de la VFC mediante el análisis de Poincaré, obteniendo los índices SD1, que permite valorar la variabilidad a corto plazo y SD2 que cuantifica la variabilidad total de los intervalos R-R. De los resultados se destaca que, en comparación con la W basal, durante la privación total de sueño aumentó el SDNN, la LF y SD2. En comparación con el sueño NREM basal, la potencia LF fue mayor durante el sueño NREM luego de su privación, y el índice LF/HF fue mayor durante el sueño NREM asociado a la privación de sueño REM. En este trabajo describimos que la VFC está fuertemente afectada tanto por el sueño como por su privación. Nuevas aproximaciones experimentales son necesarias para comprender los mecanismos neurales que subyacen a las alteraciones de la VFC gatilladas por la privación de sueño.

Importancia del buen dormir en nuestros pacientes / Importance of good sleep in our patients

El sueño es una necesidad biológica. Regula las funciones inmunitarias. Las funciones inmunológicas dependen de los ritmos circadianos y del sueño regular. Según estudios previos a la pandemia, la corta duración del sueño o privación de sueño, en la semana cercana a la vacunación, se asocia con respuestas más bajas de anticuerpos. La privación de sueño da como resultado una función inmunológica más deficiente (es decir, actividad reducida de las células natural killer, producción de IL-2 suprimida) así como un aumento de los niveles circulantes de marcadores inflamatorios (IL-6, TNF-α [factor de necrosis tumoral] y proteína C reactiva). Los médicos deben ser conscientes de que muchas enfermedades que mencionamos en esta resumida actualización son comórbidas con alteraciones del sueño, y es importante, por ello, enseñar a los pacientes a mejorar su comportamiento con respecto al sueño y fomentar la educación sobre higiene del sueño. Destacamos que, en el interrogatorio de cualquier especialidad médica, deben incorporarse preguntas sobre el "dormir", dado que el sueño de buena calidad es fundamental en la prevención y el tratamiento de diversas enfermedades. (AU)

Sleep is a biological necessity. Regulates immune functions. Immune functions depend on circadian rhythms and regular sleep. According to studies prior to the pandemic, short duration of sleep or sleep deprivation, in the week leading up to vaccination, is associated with lower antibody responses to vaccination. Sleep deprivation results in poorer immune function (i.e., reduced natural killer cell activity, suppressed IL-2 production) as well as increased circulating levels of inflammatory markers (IL-6, factor of tumor necrosis, C-reactive protein). Clinicians should be aware that many illnesses, which we mention in this brief update, are comorbid with sleep disturbances and it is therefore important to teach patients to improve their sleep behavior and should encourage sleep hygiene education . We emphasize that in the questioning of any medical specialty, questions about "sleep" should be incorporated, given that good quality sleep is essential in the prevention and treatment of various diseases. (AU)

Distúrbios do sono: escalas subjetivas e fatores associados em profissionais da saúde em jornada de plantões / Sleep disorders: subjective scales and associated factors in healthcare professionals during their duties

Objetivo: Demonstrar fatores envolvidos nos distúrbios do sono em profissionais que fazem plantões. Métodos: Trata-se de estudo transversal, cuja amostra foi composta de 244 voluntários, plantonistas da área da saúde, sendo 191 do sexo feminino, que responderam a um questionário socioeconômico, associado à aplicação da Escala de Sonolência de Epworth e ao Índice de Qualidade do Sono de Pittsburgh. Os dados foram analisados pelos coeficientes de Spearman e de Kendall Tau, com distribuição de probabilidade gama. Resultados: Houve significância (p<0,05) com o Índice de Qualidade do Sono de Pittsburgh e a atividade física (+0,216), ergonomia (+0,148), filhos (-0,146), valor da remuneração (+0,112) e disfunção durante o dia (+0,352). Também houve significância com a Escala de Sonolência de Epworth e atividade física (+0,138), renda familiar (-0,118), trabalho semanal (-0,151), latência do sono (-0,106), duração do sono (-0,107), eficiência do sono (-0,139) e disfunção durante o dia (+0,170). Por fim, a eficiência do sono teve significiância com profissão (-0,209), tabagismo (+0,402), Escala de Sonolência de Epworth (-0,139) e dissonias com a obesidade (índice de massa corporal >30; razão de chance de 1,40; intervalo de confiança de 95% de 1,02-1,94). Conclusão: As medidas autorrelatadas são prontamente obtidas com questionários validados, como a Escala de Sonolência de Epworth e o Índice de Qualidade do Sono de Pittsburgh, encontrando-se correlações com renda familiar, ter ou não filhos, índice de massa corporal, atividade física, ergonomia, condições de trabalho, tabagismo e componentes biopsicossociais. Em virtude do caráter transversal deste estudo é indispensável mais estudos com maior follow-up.

Objective: To demonstrate factors involved in sleep disorders in professionals who take shifts. Methods: This is a cross-sectional study whose sample consists of 244 volunteers, on-duty health workers, 191 females, who answered a socioeconomic questionnaire, associated with application of the Epworth Sleepiness Scale and the Pittsburgh Sleep Quality Index. Data were analyzed with Spearman's and Kendall Tau coefficients, and gamma probability distribution. Results: There was significance (p<0,05) with the Pittsburgh Sleep Quality Index and physical activity (+0,216), ergonomics (+0,148), children (-0,146), the wage (+0,112), dysfunction during the day (+0,352). Also there was significance with the Epworth Sleepiness Scale and physical activity (+0,138), family income (-0,118), weekly workload (-0,151), sleep latency (-0,106), sleep duration (-0,107), sleep efficiency (-0,139), and dysfunction during the day (+0,170). Finally, sleep efficiency was significant with occupation (-0,209), smoking habits (+0,402), Epworth Sleepiness Scale (-0,139), dyssomnia with obesity (body index mass >30; OR of 1,40; CI 95% 1,02-1,94). Conclusion: Self-reported measures are readily obtained with validated questionnaires such as Epworth Sleepiness Scale and Pittsburgh Sleep Quality Index, with correlations with family income, having children or not, body mass index, physical activity, ergonomics, working conditions, smoking habits, and biopsychosocial components. Due to the cross-sectional nature of this study, further research with longer follow-up is indispensable.

Subjective sleep need and daytime sleepiness in adolescents / Necessidade subjetiva de sono e sonolência diurna em adolescentes

ABSTRACT Objective: To analyze the contribution of subjective sleep need for daytime sleepiness in adolescents, and to compare questions about sleep, age and body mass index between adolescents who considered to sleep enough and those who reported the need for more sleep. Methods: This is a descriptive, epidemiological and cross-sectional study. Data collection was performed in August 2016, with 773 adolescents aged 14-19 years old, from Paranaguá, Paraná, Southern Brazil. The analysis included the following variables: time in bed, half-sleep phase, sleep need, social jetlag, daytime sleepiness, body mass index and physical activity. Results: The prevalence of adolescents with subjective need for sleep was 73.0%, with an average need of 1.7 extra hours of sleep. These adolescents woke up earlier (p<0.001) and slept less on school days (p<0.001). The need for more sleep was associated with higher daytime sleepiness scores (rho=0.480; p<0.001) and with later half-sleep phase (rho=0.200; p<0.001). No correlation was identified between the sleep need and time in bed (rho=-0.044; p=0.225). The subjective sleep need was the variable with the greatest explanatory power for daytime sleepiness (24.8%; p<0.001). In addition, the less adolescents practiced physical activity, the higher their daytime sleepiness scores (rho=-0.117; p<0.001). Conclusions: The subjective sleep need has an important role in explaining daytime sleepiness among adolescents. Adolescents who needed to sleep more reported waking up early and experienced sleep deprivation during class days; they also woke up later on the weekends and experienced more daytime sleepiness, compared to those who believed they had enough sleep.

RESUMO Objetivo: Analisar a contribuição da necessidade subjetiva de sono para a sonolência diurna em adolescentes e comparar questões sobre sono, idade e índice de massa corporal entre os adolescentes que consideram dormir o suficiente e os que julgam necessitar dormir mais. Métodos: Estudo descritivo, epidemiológico e transversal, cuja coleta de dados ocorreu em agosto de 2016 em 773 adolescentes de 14 a 19 anos de Paranaguá, PR, Brasil. As variáveis de análise foram tempo de cama, meia fase do sono e necessidade de mais horas de sono, além do jetlag social, sonolência diurna, índice de massa corpórea (IMC) e atividade física. Resultados: A prevalência de adolescentes com necessidade subjetiva de sono foi 73,0%, sugerindo precisar, em média, de 1,7 hora a mais de sono. Estes acordavam mais cedo (p<0,001) e dormiam menos nos dias de aula (p<0,001). A necessidade de dormir mais associou-se a maiores pontuações de sonolência diurna (rho=0,480; p<0,001) e com meia fase do sono mais tardia (rho=0,200; p<0,001). Não foi identificada correlação entre necessidade de sono e tempo de cama (rho=-0,044; p=0,225). A necessidade subjetiva de sono foi a variável com maior poder explicativo da sonolência diurna (24,8%; p<0,001). Além disso, quanto menos os adolescentes praticavam atividade física, maiores as pontuações de sonolência diurna (rho=-0,117; p<0,001). Conclusões: A percepção subjetiva de sono teve papel importante para explicar a sonolência diurna dos adolescentes. Os jovens que precisavam dormir mais relataram acordar mais cedo e apresentavam privação de sono durante os dias de aula, acordaram mais tarde no final de semana e apresentaram maior sonolência diurna, comparando-se aos que acreditavam dormir o suficiente.

Sleep and weight-height development / Sono e desenvolvimento pondero-estatural

Abstract Objectives: To describe the association between sleep duration and weight-height development in children and adolescents. Source of data: A non-systematic search in the MEDLINE database was performed using the terms anthropometry, body composition, overweight, obesity, body mass index, growth, length, short stature, sleep, children, and infants and adolescents, limited to the last 5 years. The references cited in the revised articles were also reviewed, when relevant. Synthesis of data: Sleep disorders are prevalent in the pediatric population. Among them, insomnia, which leads to a reduction in total sleep time, is the most prevalent disorder. Evidence found in the current literature allows the conclusion that sleep time reduction has a role in the current pandemic of overweight and obesity. Studies associating sleep deprivation and deficit in height growth are still insufficient. Conclusions: The association between shorter sleep duration and risk of overweight and obesity is well established for all pediatric age groups. However, more evidence is needed to establish an association between insufficient sleep duration and height growth deficit. Pediatricians should include the encouragement of healthy sleep habits in their routine guidelines as an adjuvant in the prevention and management of excess weight.

Resumo Objetivos: O objetivo deste artigo é descrever a associac¸ão entre a durac¸ão de sono e o desenvolvimento pondero-estatural entre crianc¸as e adolescentes. Fontes de dados: Foi realizada uma busca não-sistemática na base de dados MEDLINE utilizando os termos antropometria, composic¸ão corporal, sobrepeso, obesidade, índice de massa corporal, crescimento, comprimento, baixa estatura, sono, crianc¸as, lactentes e adolescentes, limitadas aos últimos cinco anos. As referências citadas nos artigos revisados também foram, conforme relevância, revisados. Síntese dos dados: Distúrbios do sono são prevalentes na população pediátrica. Dentre eles, a insônia, que cursa com redução do tempo total de sono, é a mais prevalente. Evidências presentes na literatura atual permitem apontar que a redução do tempo de sono tem um papel na pandemia atual de sobrepeso e obesidade. Os estudos que associam a privação de sono com déficit no crescimento estatural ainda são insuficientes. Conclusões: A associação entre menor duração de sono e risco para sobrepeso e obesidade está bem estabelecida para todas as faixas etárias da pediatria. Entretanto, maiores evidências são necessárias para que se possa estabelecer uma associação entre duração insuficiente de sono e déficit no crescimento estatural. O médico pediatra deve incluir nas suas orientações de rotina o estímulo a hábitos de sono saudáveis como coadjuvante na prevenção e manejo do excesso de peso.

Efeito do Treinamento Resistido na Contratilidade Miocárdica In Vitro após a Privação de Sono / Effect Of Resistance Training On Myocardial Contractility In Vitro After Sleep Deprivation

Fundamento: O treinamento resistido promove benefícios à saúde cardiovascular, a qual é influenciada pela privação de sono. Objetivo: Investigar o efeito prévio do treinamento resistido de alta intensidade sobre a contratilidade miocárdica de ratos privados de sono paradoxal. Métodos: Quarenta ratos machos Wistar foram distribuídos nos grupos controle (CTRL), treinamento resistido (TRES), privação de sono paradoxal por 96 horas (PSP96) e treinamento resistido seguido de privação de sono paradoxal por 96 horas (TRES/PSP96). O treinamento resistido foi de alta intensidade, por 8 semanas, 5x/semana. Vinte e quatro horas após a última sessão de treinamento, os grupos PSP96 e TRES/PSP96 foram submetidos ao protocolo de privação de sono paradoxal e em seguida foi realizado o estudo in vitro da mecânica contrátil do músculo papilar isolado. Resultados: Em comparação ao CTRL, os grupos PSP96 e TRES/PSP96 apresentaram menor comprimento do músculo papilar e aumento da área de secção transversa. Associado a essas alterações, verificou-se a diminuição das derivadas temporais da força na contração e relaxamento em todas as condições avaliadas. Somente o grupo PSP96 apresentou redução da tensão de repouso e lentidão no tempo de relaxamento, sendo este último atenuado pelo treinamento resistido prévio. Conclusão: O treinamento resistido prévio à PSP foi parcialmente protetor contra as alterações contráteis do músculo papilar, minimizando a lentidão no tempo de relaxamento. Assim, o caráter de alta intensidade do protocolo adotado parece não proteger plenamente o tecido cardíaco frente a PSP

Background: Resistance training promotes cardiovascular health benefits that may affected by sleep deprivation. Objective: To evaluate the effect of high-intensity resistance training on myocardial contractility in rats subsequently subjected to paradoxical sleep deprivation. Methods: Forty male Wistar rats were distributed into control group (CTRL), resistance training (REST), 96-hour paradoxical sleep deprivation (PSD96) and resistance training followed by 96-hour paradoxical sleep deprivation (REST/PSD96). The animals underwent highintensity resistance training for 8 weeks, 5x/week. Twenty-four hours after the last training session, the PSD96 and REST/PSD96 groups were submitted to paradoxical sleep deprivation, which was followed by the in vitro study of isolated papillary muscle contractile mechanics. Results: In comparison with the CTRL group, a lower papillary muscle length and increased cross sectional area were found in PSD96 and RETS/PSD96, which were associated with decreased temporal parameters of contraction force and relaxation. Decreased resting tension and slowing of relaxation time were found in the PSD96 group only. This effect was attenuated by previous resistance training. Conclusion: Resistance training partially prevented contractile changes induced by PSD, minimizing the slowing in relaxation time. Thus, high-intensity exercise seems to not fully protect the cardiac tissue from PSD-induced effects

Autonomic and Renal Alterations in the Offspring of Sleep-Restricted Mothers During Late Pregnancy

OBJECTIVES: Considering that changes in the maternal environment may result in changes in progeny, the aim of this study was to investigate the influence of sleep restriction during the last week of pregnancy on renal function and autonomic responses in male descendants at an adult age. METHODS: After confirmation of pregnancy, female Wistar rats were randomly assigned to either a control or a sleep restriction group. The sleep-restricted rats were subjected to sleep restriction using the multiple platforms method for over 20 hours per day between the 14th and 20th day of pregnancy. After delivery, the litters were limited to 6 offspring that were designated as offspring from control and offspring from sleep-restricted mothers. Indirect measurements of systolic blood pressure (BPi), renal plasma flow, glomerular filtration rate, glomerular area and number of glomeruli per field were evaluated at three months of age. Direct measurements of cardiovascular function (heart rate and mean arterial pressure), cardiac sympathetic tone, cardiac parasympathetic tone, and baroreflex sensitivity were evaluated at four months of age. RESULTS: The sleep-restricted offspring presented increases in BPi, glomerular filtration rate and glomerular area compared with the control offspring. The sleep-restricted offspring also showed higher basal heart rate, increased mean arterial pressure, increased sympathetic cardiac tone, decreased parasympathetic cardiac tone and reduced baroreflex sensitivity. CONCLUSIONS: Our data suggest that reductions in sleep during the last week of pregnancy lead to alterations in cardiovascular autonomic regulation and renal morpho-functional changes in offspring, triggering increases in blood pressure.

The influence of sleep deprivation and obesity on DNA damage in female Zucker rats

OBJECTIVE: The aim of this study was to evaluate overall genetic damage induced by total sleep deprivation in obese, female Zucker rats of differing ages. METHOD: Lean and obese Zucker rats at 3, 6, and 15 months old were randomly distributed into two groups for each age group: home-cage control and sleep-deprived (N = 5/group). The sleep-deprived groups were deprived sleep by gentle handling for 6 hours, whereas the home-cage control group was allowed to remain undisturbed in their home-cage. At the end of the sleep deprivation period, or after an equivalent amount of time for the home-cage control groups, the rats were brought to an adjacent room and decapitated. The blood, brain, and liver tissue were collected and stored individually to evaluate DNA damage. RESULTS: Significant genetic damage was observed only in 15-month-old rats. Genetic damage was present in the liver cells from sleep-deprived obese rats compared with lean rats in the same condition. Sleep deprivation was associated with genetic damage in brain cells regardless of obesity status. DNA damage was observed in the peripheral blood cells regardless of sleep condition or obesity status. CONCLUSION: Taken together, these results suggest that obesity was associated with genetic damage in liver cells, whereas sleep deprivation was associated with DNA damage in brain cells. These results also indicate that there is no synergistic effect of these noxious conditions on the overall level of genetic damage. In addition, the level of DNA damage was significantly higher in 15-month-old rats compared to younger rats.

Impacto que tiene la falta de sueño sobre las habilidades cognitivas de una población de estudiantes de medicina / Impact of sleep deprivation on the cognitive abilities of a population of medical students

Los estudiantes que ingresan a la Escuela de Medicina son personas que pasarán los próximos años de su vida preparándose para entender la composición, la anatomía y la fisiología tanto normal como patológica del cuerpo humano con el fin de luego, aplicar ese conocimiento en el tratamiento de sus pacientes. Sin embargo, ser estudiante de Medicina se ha descrito como un extenuante proceso en el cual los jóvenes sufren alteraciones notables en sus horas de sueño, niveles de estrés, presión y fustración emocional e incluso depresión. Esta investigación se llevó a cabo para identificar en una población de estudiantes de segundo semestre de segundo año de Medicina de la Universidad de Costa Rica, el deterioro cognitivo que puede tener dicho estilo de vida y cómo influye en la capacidad de aprendizaje y los resultados que estos pueden obtener. A través de la figura compleja de Rey-Osterrieth y la prueba MoCA (Montreal Cognitive Assesment) se evaluó la muestra en dos oportunidades distintas: al encontrarse los estudiantes en un período de evaluación normal y con un nivel de cansancio notable tras un período de evaluación más intenso. Los datos obtenidos comprobaron que efectivamente existe un deterioro en el rendimiento y las capacidades cognitivas de los jóvenes...

A link between sleep loss, glucose metabolism and adipokines

The present review evaluates the role of sleep and its alteration in triggering problems of glucose metabolism and the possible involvement of adipokines in this process. A reduction in the amount of time spent sleeping has become an endemic condition in modern society, and a search of the current literature has found important associations between sleep loss and alterations of nutritional and metabolic contexts. Studies suggest that sleep loss is associated with problems in glucose metabolism and a higher risk for the development of insulin resistance and type 2 diabetes mellitus. The mechanism involved may be associated with the decreased efficacy of regulation of the hypothalamus-pituitary-adrenal axis by negative feedback mechanisms in sleep-deprivation conditions. In addition, changes in the circadian pattern of growth hormone (GH) secretion might also contribute to the alterations in glucose regulation observed during sleep loss. On the other hand, sleep deprivation stress affects adipokines - increasing tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) and decreasing leptin and adiponectin -, thus establishing a possible association between sleep-debt, adipokines and glucose metabolism. Thus, a modified release of adipokines resulting from sleep deprivation could lead to a chronic sub-inflammatory state that could play a central role in the development of insulin resistance and type 2 diabetes mellitus. Further studies are necessary to investigate the role of sleep loss in adipokine release and its relationship with glucose metabolism.

La reducción del sueño como factor de riesgo para obesidad / Sleep deprivation as a risk factor for obesity

Nocturnal sleep patterns may be a contributing factor for the epidemic of obesity. Epidemiologic ana experimental studies have reported that sleep restriction is an independent risk factor for weight gain and obesity. Moreover, sleep restriction is significantly associated with incidence and prevalence of obesity and several non-transmissible chronic diseases. Experimental sleep restriction is related to altered plasma leptin and ghrelin concentrations. Both hormones are directly related to appetite and satiety mechanisms. Also, a higher activity of the orexin/hypocretin system has been reported, as well as changes in glucose metabolism and autonomic nervous system. Some studies indicate that these endocrine changes could be associated with a higher diurnal food intake and preference for energy- dense foods. All these changes could result in a positive energy balance, leading to weight gain and a higher obesity risk in the long-term. The present article summarizes the epidemiologic and experimental evidence related to sleep deprivation and higher obesity risk. The possible mechanisms are highlighted.

Efeito da privação de sono no sistema cardiovascular / The effect of sleep deprivation on cardiovacular system

A privação de sono tem se tornado uma situação frequente na sociedade moderna. A excessiva demanda econômica e social numa sociedade 24 horas tem feito os indivíduos reduzirem seu tempo de sono para suprir as exigências do mercado de trabalho. A privação de sono pode ser tanto aguda (por exemplo, ficar uma noite sem dormir), seletiva (perda de uma fase específica do sono), como também parcial e crônica (dormir poucas horas por um período prolongado). Atualmente, a privação de sono tem recebido particular atenção em virtude das consequências deletérias que exerce na saúde dos indivíduos, incluindo os distúrbios metabólicos e cardiovasculares. Essas situações representam um estresse fisiológico ao organismo , uma vez que possuem grande impacto negativo aos vários sistemas, incluindo o sistema cardiovascular. O desenvolvimento das doenças cardiovasculares, decorrentes da privação do sono tem sido amplamente discutido na literatura e depende intimamente da condição em que essa privação é imposta (total, parcial ou seletiva), visto que os mecanismos que mantêm o sistema cardiovascular estável respondem diferentemente a cada uma delas. Estudos sugerem causas multifatoriais, incluindo...

Paradoxical sleep deprivation: neurochemical, hormonal and behavioral alterations: evidence from 30 years of research

Sleep comprises approximately one-third of a person's lifetime, but its impact on health and medical conditions remains partially unrecognized. The prevalence of sleep disorders is increasing in modern societies, with significant repercussions on people's well-being. This article reviews past and current literature on the paradoxical sleep deprivation method as well as data on its consequences to animals, ranging from behavioral changes to alterations in the gene expression. More specifically, we highlight relevant experimental studies and our group's contribution over the last three decades.

O sono ocupa cerca de um terço de nossas vidas, entretanto seu impacto na saúde e sua influência nas condições patológicas ainda não foi completamente elucidado. A prevalência dos distúrbios de sono é cada vez maior, sobretudo nas regiões mais industrializadas, repercutindo diretamente no bem-estar da população. Este artigo tem como objetivo sintetizar e atualizar a literatura a respeito do método de privação de sono paradoxal e seu panorama de conseqüências desde comportamentais até genéticas em animais. Ainda, destacamos a contribuição e relevância dos estudos experimentais realizados por nosso grupo nas ultimas três décadas.

Efectos de la privación de sueño en el desempeño de los médicos residentes de pediatría / Effects of sleep deprivation on medical performance of pediatric residents

Introducción. El desempeño de los médicos residentes puede ser afectado adversamente por la privación de sueño producto de las jornadas extendidas de trabajo. Objetivo. Valorar los efectos de la privación de sueño luego de la guardia sobre la velocidad de reacción, atención y memoria en los médicos residentes de pediatría. Población, material y método. Se realizó un estudio descriptivo con evaluación antes y después. Se incluyeron 44 médicos residentes, distribuidos en dos grupos. Al primer grupo (23 residentes) se le realizaron dos evaluaciones, en un día libre de guardia y luego de una guardia. El segundo grupo se evaluó sólo luego de una guardia y fue utilizado para valorar el efecto aprendizaje. Todos los participantes realizaron: cuestionario que incluyó horas de sueño, escala de sueño de Epworth, inventario de desgaste profesional (burnout) de Maslach, trail making test, prueba PASAT, span de dígitos, batería de memoria de Signoret y prueba de tiempo de reacción. Se evaluó el grado de deterioro en las pruebas luego de un día de guardia. Resultados. El promedio de horas de sueño el día de guardia fue de 3 h. Se observó deterioro significativo en las pruebas de velocidad de reacción visual (p< 0,001). Las pruebas de atención y la memoria no presentaron empeoramiento luego de la guardia. Conclusión. La velocidad de reacción resulta deteriorada por la privación de sueño que experimentan los médicos residentes.

Effects on prolactin secretion and binding to dopaminergic receptors in sleep-deprived lupus-prone mice

Sleep disturbances have far-reaching effects on the neuroendocrine and immune systems and may be linked to disease manifestation. Sleep deprivation can accelerate the onset of lupus in NZB/NZWF1 mice, an animal model of severe systemic lupus erythematosus. High prolactin (PRL) concentrations are involved in the pathogenesis of systemic lupus erythematosus in human beings, as well as in NZB/NZWF1 mice. We hypothesized that PRL could be involved in the earlier onset of the disease in sleep-deprived NZB/NZWF1 mice. We also investigated its binding to dopaminergic receptors, since PRL secretion is mainly controlled by dopamine. Female NZB/NZWF1 mice aged 9 weeks were deprived of sleep using the multiple platform method. Blood samples were taken for the determination of PRL concentrations and quantitative receptor autoradiography was used to map binding of the tritiated dopaminergic receptor ligands [³H]-SCH23390, [³H]-raclopride and [³H]-WIN35,428 to D1 and D2 dopaminergic receptors and dopamine transporter sites throughout the brain, respectively. Sleep deprivation induced a significant decrease in plasma PRL secretion (2.58 ± 0.95 ng/mL) compared with the control group (25.25 ± 9.18 ng/mL). The binding to D1 and D2 binding sites was not significantly affected by sleep deprivation; however, dopamine transporter binding was significantly increased in subdivisions of the caudate-putamen - posterior (16.52 ± 0.5 vs 14.44 ± 0.6), dorsolateral (18.84 ± 0.7 vs 15.97 ± 0.7) and ventrolateral (24.99 ± 0.5 vs 22.54 ± 0.7 µCi/g), in the sleep-deprived mice when compared to the control group. These results suggest that PRL is not the main mechanism involved in the earlier onset of the disease observed in sleep-deprived NZB/NZWF1 mice and the reduction of PRL concentrations after sleep deprivation may be mediated by modifications in the dopamine transporter sites of the caudate-putamen.

[Sleeplessness effect on the general health of hospitals nightshift nurses in Gorgan, Iran]

Nightshift working has negative physical, psychological and social effects on personal life of nurses and in the long run, with subsequent health and complication. This survey was done to study the effect of sleeplessness on general health of nightshift nurses in hospitals of Golestan University of Medical Sciences, Gorgan, Iran, during 2008. In this descriptive study, 124 subjects with suitable condition were selected through a census from among 615 nightshift working nurses in hospitals of Golestan university of medical sciences. Data were collected by delivering questionnaire and it included one questionnaire of personal information and two questionnaires about effects of sleeplessness and general health [GHQ-28]. Effect of sleeplessness, in the maximum percent of nurses [55.6%] were moderate and in the minimum percent [2.4%] were low. Mean +/- SD the sleepness rate was moderate [58 +/- 9]. Also, the results of general health showed that most of them [60.6%] had favorable general health and 2.5% of subjects had unfavorable general health. There was a significant correlation between sleepness, effect and general health of nurses in addition. There was also a meningfull sleeplessness correlation between sleepness effect with age, employment history and nightschieft time table [P<0.05]. This study showed that sleepness, negatively, effect on general health of nightschieft nurses, it is suggested, there should a properly organized sleep time table for the nightchieft nurses

Privação de sono e exercício físico / Sleep deprivation and exercise

A privação do sono é a remoção ou supressão parcial do sono, e esta condição pode causar diversas alterações: endócrinas, metabólicas, físicas, cognitivas, neurais e modificações na arquitetura do sono, que em conjunto comprometem a saúde e a qualidade de vida do sujeito nestas condições. Já o exercício físico praticado regularmente promove benefícios como melhora do aparato cardiovascular, respiratório, endócrino, muscular e humoral, além disso, pode melhorar a qualidade do sono. Entretanto, a associação desses dois parâmetros não tem sido bem explorada, em parte pela dificuldade conseguir voluntários que se submetam a essa condição principalmente sem nenhum tipo de compensação financeira. A maioria dos estudos que investigaram o binômio exercício físico e privação de sono focou os efeitos no desempenho aeróbio. Embora ainda haja controvérsias, os estudos apontam para pequena ou nenhuma alteração desse parâmetro quando as duas situações se fazem presentes. Em relação à potência anaeróbia e força não tem sido encontrados alterações significativas, mas para eventos prolongados, parece haver uma interação entre a privação de sono e o exercício físico, o que sugere um mecanismo de proteção. Entretanto, é importante considerar que uma das alterações mais importantes causadas pela privação do sono é o aumento na percepção subjetiva, que por si só já representa um fator para diminuição e comprometimento do desempenho físico e pode representar um elemento de "mascaramento" dos efeitos deletérios da privação. Assim, o objetivo da presente revisão é o de discutir os diferentes aspectos da relação entre o exercício físico e a privação de sono, evidenciando seus efeitos e reflexos no desempenho físico.

Sleep deprivation can be defined as total or partial suppress of sleep and is associated with alterations in endocrine, metabolic, physical, cognitive functions and modifications of the sleep patterns that compromise health and quality of life. Physical exercise is associated with improvement of cardiovascular, respiratory, muscular, endocrine and nervous system, and a better sleep quality. However, the association of these two conditions is unclear, partly due to the difficulty to obtain volunteers to participate in this type of protocol with no financial compensation. The majority of the studies which investigate the association between physical exercises and sleep deprivation focus on aerobic performance and verify little or no effect of this parameter. Concerning anaerobic power and strength, significant alterations have not been found; however, for prolonged events there may be an interaction between these two factors, which suggests a protection mechanism. Nevertheless, it is important to consider that one of the main alterations caused by sleep deprivation the increase of the subjective perception, which presents a factor to decrease and compromise the physical performance per se, and may represent a masking element of the deleterious effects of sleep deprivation. Thus, the aim of present review is to discuss the different aspects of relationship between physical exercise and sleep deprivation, showing their effects and consequences in physical performance.