Sleep patterns in villagers and urban African volunteers in a humid tropical climate: Influence of accessibility to electric light?

From pole to pole, life-long research of sleep in extreme environments

In November 1965, Michel Jouvet accepted me into his laboratory in Lyon as a medical student at a time when sleep research was an adventure. After 4 years of investigations in cats, I obtained my medical doctorate. Being a military physician, I was posted to Antarctica for wintering over and was initiated by Jean Rivolier into the psychology of small isolated human groups. I recorded 180 polysomnographic (PSG) nights in eight of my companions. This was my first contribution to research on human sleep under extreme environments and conditions. I then entered René Hénane's military thermophysiology laboratory, where I analyzed thermal exchanges during human sleep in the heat. Back to the cold, I spent 2 years in Canada and analyzed sleep during the Arctic winter under the direction of Manny W. Radomski, who headed the Defense and Civil Institute of Environmental Medicine and judged my PhD dissertation along with my first two mentors. Throughout my career, I worked in collaboration with Manny Radomski under the auspices of the Franco-Canadian Accord for Defence Research. We studied sleep and exercise, sleep deprivation, and recovery with and without chemical help. He also gave me support during several investigations in Africa. There, I studied normal sleep under various tropical climates (warm and dry in Niger, warm and humid in Côte d'Ivoire and Congo, temperate mid-mountain in Angola). I determined that human African trypanosomiasis, the ravaging sleeping sickness or tsetse disease, is not a hypersomnia, but a disorder of circadian rhythms, notably in the sleep-wake cycle.

Sleep and global warming: How will we sleep when the Earth is hotter?

Societal concern about climate change and global warming has grown worldwide along with the concomitant awareness that health will be impacted deeply. Among living beings, humans have quite large capacities for adaptation to varied temperature conditions. Despite their tropical origin, they live under all Earth climates, such as polar, temperate, altitude, arid, and tropical climates, using a wide range of behavioral and physiological adaptive responses. We address the adaptive abilities of human sleep-wake regulation and its interplay with thermoregulation under different natural climates. Sleep represents one-third of our living time and is also a major determinant of morbidity and mortality; shortening sleep duration increases mortality and multimorbidity. In addition, major advances in sleep neurology have occurred in the last decades. Some have been extensively reviewed, notably comparative sleep physiology among animals, allowing one to hypothesize about the functions of the different sleep states, as well as their relation to cognitive neuroscience or body biorhythms. However, the question of the sleep adaptive capacity of humans to global warming has barely been addressed. We examine "normal" sleep and thermoregulation in young adults residing in temperate conditions. We then review the sleep and thermoregulatory reactions under various climatic conditions, demonstrating the role of sleep changes as potent adaptive responses to living under natural hot climatic conditions. As a result, we show that humans are well-equipped to adapt to severe climates.

Self-reported sleep duration, sleep quality and sleep problems in Mexicans adults: Results of the 2016 Mexican National Halfway Health and Nutrition Survey

OBJECTIVE

This study aimed to investigate self-reported sleep duration, sleep quality and sleep problems in a Mexican adult population by considering age, sex, geographical regions and urban/rural residency.

DESIGN/MEASUREMENTS

Cross-sectional national adult survey based on the 2016 Mexican National Halfway Health and Nutrition Survey data.

SETTING

Nationally representative survey data.

PARTICIPANTS

Mexican adults ≥ 18 years, n = 8649 (N weighted = 71,158,260 adults).

RESULTS

Overall, mean sleep duration was 7:19 hours, from which 37% had sleep problems, and 45.7% reported very good sleep quality. Furthermore, middle-aged adults slept less than younger and older adults, females were at lower risk of being a short sleeper than males, urban residents slept less than rural residents, and those from the center region of the country slept less than from the northern and southern regions. Mainly, participants from the state of Quintana Roo, Aguascalientes, and Baja California reported sleep duration <7 hours (6:26 hours, 6:45 hours, and 6:55 hours, respectively). Overall Mexicans who obtained sufficient sleep (≥8 hours) were more likely to be female, in their 20s, reporting perceived "good" or "very good" sleep quality, possessed no self-reported sleep problems, were not a tobacco user, and resided in rural areas. Furthermore, Mexicans who obtained poor sleep quality were more likely to be females that reported sleep problems, took sleep medications, and resided in urban areas.

CONCLUSION

The present study's findings have important implications for understanding the nationwide features of sleep in Mexican adults. Education and public health awareness initiatives regarding good sleep may be warranted.

Michel Jouvet and "exotic" sleep

Michel Jouvet directed my medical thesis on paradoxical sleep in cats obtained in 1969, and my research on sleep in extreme environments (Antarctica, Arctic winter cold, physical exercise), which was the subject of my Ph.D. dissertation in 1984. As a military MD and scientist, I was posted in "exotic" (far away) places (Antarctica, Canada, Niger) and participated in several remote field trials (Canada, Côte d'Ivoire, Congo, Angola). Michel Jouvet supervised my research activity, allowing me the use of his laboratory facilities. He co-authored the work on sleep in Antarctica in 1987. In 1988, he was invited to Niamey (Niger) to preside on the international jury of medical doctorate dissertations. He then examined one of my patients with narcolepsy-like sleep attacks, suspect of sleeping sickness. Jouvet also co-authored our work on nitric oxide in the rat model of sleeping sickness. His scientific curiosity led him to study REM sleep eye movements in Bassari people, an isolated ethnic group in Senegal. With Monique Gessain, he co-authored a book on the Bassari oneiric activity. He was convinced that research in electricity-free villages was capital for understanding past mankind story. The present contribution recognizes the tremendous work capacity and scientific curiosity of Michel Jouvet.