Sleep and cognition
2 papers in the library, strongest Moderate.
Graded Moderate · More than 57,000 older adults were followed for nearly eight years, with results confirmed in a second group; as an observational study it cannot show cause.
Papers 2
- Slow Days, Restless Nights: Wrist Sensor Helps Predict DementiaModeraten = 57,4132026JAMA neurologyHow older people move during the day and sleep at night says something about their later dementia risk. Those with little brisk activity and restless sleep developed dementia more often. A wrist sensor worn for one week made dementia prediction a little more accurate. Researchers used data from 53,448 people aged 60 or older in the UK Biobank. Each wore a movement sensor for seven days, and were then followed for nearly eight years on average. A computer method picked two patterns out of 36 measurements. The first: short, rare bouts of brisk movement, lots of light activity and quick switches to rest. People who showed this pattern clearly more than average had a 43 percent higher dementia risk. The second pattern, very short or very long sleep, long wake periods and early waking, came with a 10 percent higher risk. A second group of 3,965 people confirmed the results. Compared with predicting by age alone, the patterns improved accuracy about as much as testing for the known risk gene APOE. The gain was modest, though. The study cannot say whether movement and sleep help cause dementia or are early signs of it. Only one week was measured, and participants were healthier than the general population.
- Review: Muscle Loss May Link Poor Sleep to Alzheimer's RiskPreliminary2026Neuroscience and biobehavioral reviewsSleep often becomes lighter and more broken with age. That is thought to be one possible reason the brain grows more vulnerable to Alzheimer's. Less deep sleep and frequent waking may help harmful proteins such as amyloid and tau build up. One researcher now argues that the muscles belong in this picture too. In his review, he brings together work on sleep, aging and metabolism. His idea: age-related muscle loss, muscle loss combined with obesity, and insulin resistance may disturb sleep. Insulin resistance means the body's cells respond poorly to insulin. Together with low-level inflammation, these conditions might let broken sleep harm the brain more easily. As a possible go-between he points to irisin, a messenger from muscle linked to a growth factor that supports nerve cells. This is a proposed model, not a new measurement. The author himself stresses that direct evidence for irisin playing a causal role in human sleep is lacking. He sets out predictions that experiments can test. In time, the model might help combine better sleep, strength training and metabolic treatment.
How this map is computed
A mark's size is the number of papers we hold on that pairing. It is a count, not a weighting by study design or sample size.
The fill shows the strongest grade in the cell. One Strong paper among four Preliminary ones still fills it dark, so open the cell to see the rest.
Grades and verdicts are assigned by a named person, never by counting.
An empty cell means our library holds no paper on that pairing yet. It is a gap in our library, not proof that nobody has studied it.