Sweden's long, cold nights might put you off going there in winter, unless, that is, you are in search of that elusive ...

If scientists could figure out what these people do differently it might, they hope, provide insight into sleep’s very nature. “The bottom line is, we don’t understand what sleep is ...

Sleep is a state characterized by a reduced responsiveness to sensory stimuli, suppressed locomotor activity and rapid reversibility to wakefulness. It is a process that is evolutionarily ...

He says people move around and often don't want ... an underestimate because of the inherently chaotic and hidden nature of rough sleeping. In London, where the problem is most severe, they ...