International Journal of Molecular Medical Science, 2025, Vol.15, No.4, 155-164 http://medscipublisher.com/index.php/ijmms 157 3.2 Cortisol’s role in stress regulation and abnormal levels in dementia patients Cortisol is a glucocorticoid released by the adrenal cortex that is central to the stress response and metabolic control. Its release follows a day–night pattern, reaching a high point in the early morning and then declining over the day, which helps maintain internal balance and supports alertness while awake (Dori et al., 1994; Ferrari et al., 2000). The hypothalamic- pituitary- adrenal (HPA) axis keeps this rhythm tightly regulated, and disruption can affect many body systems. In dementia, particularly Alzheimer’s disease, cortisol control is often impaired. Older patients commonly show higher evening and night cortisol, a smaller day-night swing, and weaker feedback sensitivity of the HPA axis. These changes become more obvious with increasing age and cognitive loss, and they are linked to more neuropsychiatric symptoms, sleep problems, and faster neurodegeneration (Dori et al., 1994; Ferrari et al., 2000; Cho et al., 2023). 3.3 Interactions between the two in circadian rhythm regulation and their impact on neurodegeneration Melatonin and cortisol act in opposite ways to shape circadian rhythms and the sleep–wake cycle. In the evening, melatonin goes up as cortisol goes down to support sleep onset, while in the morning, rising cortisol and falling melatonin help promote wakefulness (Dori et al., 1994; Ferrari et al., 2000; Lin et al., 2013). This coordinated balance is key for strong daily rhythms and normal sleep structure. In dementia, the regularity of these two important hormones is disrupted, which weakens the management of the body's internal clock, resulting in poorer sleep, behavioral changes and faster decline in thinking (Dori et al., 1994). These abnormal hormonal changes, associated with more cell damage, brain inflammation and fewer new brain cells, all accelerate the degeneration of the brain. Observing these changes and making adjustments when possible may help alleviate sleep disturbances and behavioral problems in patients with dementia (Ferrari et al., 2000; Lin et al., 2013; Sarena et al., 2022; Cho et al., 2023). 4 Sleep Management Methods Based on Nursing 4.1 Improve the environment: light, noise, temperature and humidity Making the place of care more comfortable is an important part of helping sleep in care. Reducing surrounding noise, minimizing distractions at night, and adjusting light (such as using dimmer lights or eye masks at night) can help the elderly, including those with dementia, sleep better (Figure 1) (Bellon et al., 2020; Ashghab et al., 2024; Hweidi et al., 2024). A good environment also includes maintaining the room temperature and humidity at a comfortable level, as well as the regulations of the ward that patients should not be moved at night to ensure quiet time (Bellon et al., 2022; Ashghab et al., 2024; Mendonça et al., 2024). Figure 1 Categories and subcategories of sleep-enhancing nursing interventions in hospital wards (Adopted from Mendonça et al., 2024)
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