Final answer:
Decreased skin discoloration is not a recognized biological effect of poor sleep. Instead, poor sleep can lead to hormone disruption, cognitive impairment, and metabolic disruption.
Step-by-step explanation:
All of the following are biological effects of poor sleep except decreased skin discoloration. Poor sleep can lead to a variety of negative consequences such as hormone disruption, cognitive impairment, and metabolic disruption. These effects are well-documented and can have significant impacts on an individual's overall health. For example, sleep deprivation can result in increased stress hormones, cognitive and memory deficits, and an increased risk of obesity. Hormone levels, such as melatonin and cortisol, can be affected, which in turn impacts circadian rhythms and leads to further sleep issues. However, decreased skin discoloration is not a commonly recognized effect of poor sleep.