Cardiac autonomic nervous activity during different sleep stages in individuals with spinal cord injury: The influence of physical training.

OBJECTIVE: The present study assessed the influence of physical training on cardiac autonomic activity in individuals with spinal cord injury (SCI) during different sleep stages. METHODS: Twenty-six volunteers were allocated into three groups: 9 sedentary individuals without SCI (control, CON); 8 sedentary tetraplegic individuals with chronic SCI (SED-SCI); 9 physically trained tetraplegic individuals with chronic SCI (TR-SCI). All participants underwent nocturnal polysomnography to monitor sleep stages: wakefulness, non-rapid eye movement (NREM) sleep (N1, N2, and N3 stages), and REM sleep. The electrocardiography data obtained during this exam were extracted to analyze the heart rate variability (HRV). RESULTS: Sleep stages influenced HRV in the time [RR interval and root mean square of successive RR interval differences (RMSSD)] and frequency [low-frequency (LF) and high-frequency (HF) powers and LF-to-HF ratio] domains (P < 0.05). SED-SCI individuals showed unchanged HRV compared to CON (P > 0.05). When comparing the TR-SCI and SED-SCI groups, no significant differences in HRV were reported in the time domain (P > 0.05). However, in the frequency domain, more accentuated HF power was observed in TR-SCI than in SED-SCI individuals during the N2 and N3 stages and REM sleep (P < 0.05). Moreover, TR-SCI had higher HF power than CON during the N3 stage (P < 0.05). CONCLUSIONS: TR-SCI individuals have greater HF power, indicative of parasympathetic modulation, than sedentary (injured or not injured) individuals during different sleep stages. Therefore, enhanced parasympathetic activity induced by physical training may improve cardiac autonomic modulation during sleep in individuals with chronic SCI.

Sleep regularity in athletes: Comparing sex, competitive level and sport type.

This study aims to describe the athletes' sleep regularity using the Sleep Regularity Index (SRI) and determine whether factors, such as sex, competitive level and sport type, could affect the sleep/wake rhythm. It is a descriptive, cross-sectional study consisting of 172 athletes (25 ± 7 y old; 45 women). Seventy-three competed in team sports and 99 in individual sports. Furthermore, 56 competed in the international level, 95 in the national and 21 in the regional. We recorded the SRI values for at least 5 d via continuous actigraphy. We recorded a mean SRI value of 73 ± 12. We found no significant differences between athletes' sleep parameters in relation to sleep regularity. Furthermore, SRI data showed no correlations (Spearman's ρ) with sleep parameters, bed time and wake time. Female athletes (p = 0.001) and individual sport athletes (p = 0.001) reported better sleep regularity than their counterparts. International-level athletes reported better sleep regularity than those in other competitive levels (national: p = 0.001; regional: p = 0.024). Our study showed that international level athletes, female athletes and individual sport athletes reported better sleep regularity. Additionally, SRI data showed no correlation with athletes' sleep parameters, bed and wake time.

Was postponing the tokyo 2020 olympic and paralympic games a correct decision? / O adiamento dos jogos olímpicos e paralímpicos de tóquio 2020 foi uma decisão correta? / ¿la postergación de los juegos olímpicos y paralímpicos de tokio 2020 fue una decisión correcta?

ABSTRACT In December 2019, Wuhan, in China, attracted international attention due to a pneumonia outbreak caused by the new coronavirus (2019-nCoV). Infection by 2019-nCoV is more likely in elderly people with comorbidities or with associated chronic diseases. Due to the high transmission rate among humans, this disease is rapidly disseminated, which led to several events being canceled, including the Tokyo 2020 Olympic and Paralympic Games. The aim of this article is to discuss the risk factors for Olympic and Paralympic athletes, as well as for spectators, that justify the decision to postpone the Tokyo Games 2020. Regular physical exercise is associated with health and the prevention of chronic diseases. Although athletes generally appear to be healthy and physically fit, this may not be true. The immune system, which protects the organism from invasive microorganisms, can be affected by the duration and quality of sleep, as well as by physical exercise which influences the quality of the immune response. High volumes of high-intensity physical exercise, as well as changes in sleep patterns during the pre-competition period and the impacts of jet lag on athletes traveling for the Tokyo Games in 2020 may lead to immune system suppression, making these groups more vulnerable to infection by 2019-nCoV. Moreover, during the period planned for the games in 2020 the pandemic may be subsiding in some countries and increasing in others, and this was also taken into consideration as a risk factor. Hence, the decision taken to postpone the Tokyo 2020 Olympic and Paralympic Games until 2021 due to the 2019-nCoV was the correct one, and was extremely important to protect the health of Olympic and Paralympic athletes, as well as spectators. Level of evidence V; expert opinion .

RESUMO Em dezembro de 2019, Wuhan, na China, despertou atenção internacional devido a um surto de pneumonia causada pelo novo coronavírus (2019-nCoV). A infecção pelo 2019-nCoV é mais provável em pessoas idosas com comorbidades ou com doenças crônicas associadas. Em virtude da alta taxa de transmissão entre humanos, essa doença tem disseminação rápida, o que fez com que diversos eventos fossem cancelados, dentre eles os Jogos Olímpicos e Paralímpicos de Tóquio 2020. Nesse sentido, o objetivo deste artigo é discutir fatores de risco dos atletas olímpicos e paralímpicos, bem como dos espectadores, que justificam a decisão de adiamento dos Jogos de Tóquio 2020. A prática de exercício físico regular é associada à saúde e à prevenção de doenças crônicas. Embora normalmente pareça que os atletas estão em boa forma e são saudáveis, isso pode não ser verdade. O sistema imunológico, que protege o organismo de microrganismos invasores, pode ser afetado pela quantidade e qualidade do sono, assim como pela prática de exercício físico que influencia a qualidade da resposta imunológica. A prática de exercícios de alta intensidade e grande volume, além das alterações do sono no período pré-competitivo e os impactos do jet lag dos atletas que viajariam para os Jogos de Tóquio no ano de 2020 podem levar à supressão do sistema imunológico, deixando esses grupos mais vulneráveis à contaminação pelo 2019-nCoV. Além disso, no período previsto de ocorrência dos jogos em 2020 a pandemia poderia estar em regressão em alguns países e ascensão em outros, e isso também foi levado em consideração como um fator de risco. Nesse sentido, a tomada de decisão de adiar os Jogos Olímpicos e Paralímpicos de Tóquio 2020 para o ano de 2021 devido ao 2019-nCoV foi correta e de extrema importância para preservar a saúde dos atletas olímpicos e paralímpicos, bem como dos expectadores. Nível de evidência V; opinião do especialista .

RESUMEN En diciembre de 2019, Wuhan, en China, despertó la atención internacional debido a un brote de neumonía causada por el nuevo coronavirus (2019-nCoV). La infección por el 2019-nCoV es más probable en personas de la tercera edad con comorbidades o con enfermedades crónicas asociadas. En virtud de la alta tasa de transmisión entre humanos, esta enfermedad tiene diseminación rápida, lo que hizo con que diversos eventos fuesen cancelados, entre ellos los Juegos Olímpicos y Paralímpicos de Tokio 2020. En ese sentido, el objetivo de este artículo es discutir factores de riesgo de los atletas olímpicos y paralímpicos, bien como de los espectadores, que justifican la decisión de postergación de los Juegos de Tokio 2020. La práctica de ejercicios físicos de forma regular está asociada a la salud y a la prevención de enfermedades crónicas. Aunque normalmente parezca que los atletas están en buena forma y son saludables, eso puede no ser verdad. El sistema inmunológico, que protege el organismo de microorganismos invasores, puede ser afectado por la cantidad y calidad del sueño, así como por la práctica de ejercicios físicos que influencia la calidad de la respuesta inmunológica. La práctica de ejercicios de alta intensidad y gran volumen, además de las alteraciones del sueño en el período precompetitivo y los impactos del jet lag de los atletas que viajarían para los Juegos de Tokio en el año 2020 pueden llevar a la supresión del sistema inmunológico, dejando a esos grupos más vulnerables a la contaminación por el 2019-nCoV. Además, en el período previsto de ocurrencia de los juegos en 2020 la pandemia podría estar en regresión en algunos países y ascensión en otros, y eso también fue llevado en consideración como un factor de riesgo. En ese sentido, la toma de decisión de postergar los Juegos Olímpicos y Paralímpicos de Tokio 2020 para el año 2021 debido al 2019-nCoV fue correcta y de extrema importancia para preservar la salud de los atletas olímpicos y paralímpicos, bien como de los espectadores. Nivel de evidencia V; opinión del especialista .

Sleep debt induces skeletal muscle injuries in athletes: A promising hypothesis.

Sleep is a physiological state and it is fundamental for physical and cognitive recovery of athletes. Due to strenuous training and competitions, athletes may present sleep complaints compromising good quality and quantity of sleep. Studies have related sleep debt to the occurrence of musculoskeletal injuries in athletes, but the mechanisms that can lead to this are not entirely clear. Studies involving animals and humans have shown that poor sleep quality can cause significant changes in hormones and cytokines. Demonstrating that this hormones changes lead to a decrease of testosterone and growth hormone levels and increased cortisol levels, important hormones in the process of protein synthesis and degradation. In athletes, the sport itself is a risk factor of injuries, and sleep debt may result in overtraining syndrome associated with inflammatory markers and ultimately to immune system dysfunction. Thus, we hypothesize that athletes who have sleep debt are more susceptible to musculoskeletal injuries due to increased catabolic pathway signaling, i.e. protein degradation and decreased anabolic pathway signaling, compromising muscle integrity. In this sense, we indicate the relationship between musculoskeletal injuries and sleep debt involving new targets for immunological signaling pathways that start the reduction of the muscle recovery process.

Does the compromised sleep and circadian disruption of night and shiftworkers make them highly vulnerable to 2019 coronavirus disease (COVID-19)?

Rotating and permanent night shiftwork schedules typically result in acute and sometimes chronic sleep deprivation plus acute and sometimes chronic disruption of the circadian time structure. Immune system processes and functionalities are organized as circadian rhythms, and they are also strongly influenced by sleep status. Sleep is a vital behavioral state of living beings and a modulator of immune function and responsiveness. Shiftworkers show increased risk for developing viral infections due to possible compromise of both innate and acquired immunity responses. Short sleep and sleep loss, common consequences of shiftwork, are associated with altered integrity of the immune system. We discuss the possible excess risk for COVID-19 infection in the context of the common conditions among shiftworkers, including nurses, doctors, and first responders, among others of high exposure to the contagion, of sleep imbalance and circadian disruption. ABBREVIATIONS: ACE2: Angiotensin-converting enzyme 2; APC: Antigen.-presenting .cells; CCL: Chemokine (C-C motif) ligand; CD+: .Adhesion molecule expression; COVID-19: 2019 coronavirus disease; DCs: Dendritic cells; GH: Growth hormone; HPA: Hypothalamic-pituitary-adrenal; HSF: Heat shock factor; HSP70: Heat shock protein 70; HSP90: Heat shock protein 90; IL: Interleukin; INFγ: Interferon-gamma; LT/LB: T/B lymphocytes; MHC: Major histocompatibility complex; NK: Natural .killer; RAAS: renin-angiotensin-aldosterone system; SARS: .Severe acute respiratory syndrome; SCN: Suprachiasmatic nucleus;SD: Sleep deprivation; SNS: Sympathetic nervous system; Th1/Th2: T helper lymphocytes 1/2; TLR2/TLR4: Toll-like receptor 2/4; TNF-α: Tumor .necrosis .factor alpha; VEGF: Vascular endothelial growth factor.