During stage 1 sleep, which is the first stage of non-rapid eye movement (NREM) sleep, several key physiological and neurological changes occur as the body transitions from wakefulness to sleep:

• It is a light sleep stage lasting about 1 to 7 minutes, where the individual drifts off to sleep but can be easily awakened, often not realizing they were asleep

• Heart rate, breathing rate, and eye movements begin to slow down

• Muscle activity decreases, and overall muscle tension reduces, though occasional muscle twitches called hypnic jerks may occur

• Core body temperature drops slightly as the body prepares for deeper stages of sleep

• Brain wave activity shifts from alpha waves (associated with relaxed wakefulness) to theta waves, which are slower and higher amplitude, marking the onset of sleep

• This stage serves as a transitional phase between full wakefulness and deeper sleep stages, facilitating the gradual slowing of bodily functions and brain activity

In summary, stage 1 sleep is a brief, light sleep phase characterized by slowing physiological functions, reduced muscle tone, and a shift in brain wave patterns from alpha to theta waves, marking the initial descent into sleep