According to a report by Medical News Today, the human circadian rhythm—the body's natural sleep-wake cycle—is closely linked to overall health. Previous studies have indicated that chronic disruption of the circadian rhythm may increase the risk of cardiovascular disease, metabolic abnormalities, obesity, type 2 diabetes, and dementia. A study published in Alzheimer’s & Dementia analyzed data from 344 older adults with an average age of 73 who showed no cognitive impairment. Participants wore wrist-worn activity trackers to record their 24-hour rest and activity patterns over a week and underwent brain MRI scans.

The study found that older adults with more regular daily routines and stable rest-activity rhythms typically had larger brain volumes in regions associated with memory and emotion, such as the hippocampus, parahippocampal gyrus, and amygdala. Conversely, those whose daily patterns frequently fragmented into rapid switches between activity and rest showed a tendency toward faster brain atrophy and ventricular enlargement. Notably, these same brain regions are the ones most commonly affected by Alzheimer's disease. Experts caution that while this study demonstrates a "correlation," it does not prove that an irregular routine directly causes brain atrophy. Nevertheless, maintaining a stable day-night routine may still help support healthy aging.

In daily life, one can start by waking up at a fixed time, getting exposure to natural light in the morning, maintaining moderate physical activity during the day, keeping regular meal and bedtimes, avoiding excessively long or late afternoon naps, and reducing caffeine and alcohol intake before bed. If individuals experience insomnia, sleep apnea, depression, or sleep/daytime alertness issues caused by medication, it is recommended to consult a physician or relevant medical professionals.

Source: Medical News Today, "Brain health: Staying more active during the day helps retain brain volume." Compiled and adapted from the original article.