[2026] PTE Academic Reading - Multiple Choice, Multiple Answers

Circadian rhythms are internal biological processes that follow a roughly 24-hour cycle, responding primarily to light and darkness in an organism's environment.These rhythms are regulated by the suprachiasmatic nucleus (SCN), a small region in the brain's hypothalamus that acts as the body's master clock.The SCN coordinates various physiological functions, including the sleep-wake cycle, hormone release, and body temperature regulation.One of the most critical hormones influenced by this system is melatonin, which is produced by the pineal gland to signal to the body that it is time for rest.Modern lifestyles, characterized by extensive exposure to artificial blue light from electronic devices, can significantly disrupt these natural cycles.Blue light suppresses the production of melatonin more effectively than other wavelengths, leading to delayed sleep onset and reduced sleep quality.Chronic disruption of circadian rhythms is linked to a higher risk of various health issues, such as obesity, cardiovascular disease, and metabolic disorders.Shift workers are particularly vulnerable to these disruptions, as their schedules often force them to be active when their biological clocks signal for sleep.To mitigate these effects, experts recommend maintaining a consistent sleep schedule and limiting screen time before bed to promote healthy sleep hygiene.As researchers continue to study chronobiology, the application of light therapy and timed medication is showing promise in treating circadian-related sleep disorders.