Feeling More Anxious Lately? This Sleep Stage Might Be Missing

Sleep and anxiety have always had a complicated relationship. Poor sleep can leave us emotionally fragile the next day, while stress and racing thoughts often make it harder to fall asleep in the first place. But the connection may run deeper than simply feeling tired.

As we age, both sleep and emotional regulation tend to shift. Many older adults experience lighter sleep, fewer hours in bed, and more nighttime awakenings. At the same time, anxiety symptoms can become more common later in life, and they’re increasingly recognized as a major factor influencing cognitive health and quality of life.

So researchers have started asking a bigger question: Could changes in sleep itself be part of the reason anxiety rises with age?

To explore the connection, researchers at the University of California, Berkeley recruited 61 cognitively healthy adults over the age of 65 who reported a range of anxiety levels.

Participants spent a night in a sleep lab where their brain activity was closely monitored using polysomnography, a comprehensive sleep test that tracks brain waves throughout the night. The researchers were particularly interested in slow-wave activity, the hallmark brain pattern of deep non-REM sleep.

Before and after sleep, participants also completed validated questionnaires measuring their anxiety levels.

The next morning, researchers conducted brain scans using MRI to examine structural changes in regions known to influence emotional regulation, including areas of the limbic system that often show age-related shrinkage.

A smaller group of participants was also followed for roughly four years to see whether the relationship between sleep and anxiety held up over time.

The results pointed to one clear pattern. Older adults who generated stronger slow-wave sleep tended to experience lower anxiety levels.

In contrast, participants whose deep sleep was more disrupted were more likely to report higher anxiety the following day.

Brain scans offered an additional clue. Age-related atrophy in emotion-processing regions, including the amygdala, insula, and cingulate cortex, was linked to reduced slow-wave sleep. In other words, structural changes in the brain appeared to weaken the brain’s ability to produce restorative deep sleep.

But even when some degree of brain atrophy was present, individuals who maintained stronger slow-wave sleep still showed better emotional stability.

Deep sleep doesn’t just help you feel rested; it also changes how the brain regulates emotions.

During slow-wave sleep, the nervous system shifts into a more parasympathetic, or “rest-and-recover,” state. Stress hormones quiet down, heart rate variability improves, and the brain recalibrates circuits involved in emotional control.

This stage of sleep also strengthens communication between the prefrontal cortex, the brain’s rational control center, and the limbic system, which processes fear and stress.

When deep sleep declines, that emotional regulation system becomes less stable. The result can be heightened reactivity, more persistent worry, and a greater tendency toward anxiety.

While sleep naturally changes with age, research suggests that slow-wave sleep can still be supported through daily habits.

Deep sleep isn’t just about feeling rested the next day. It may be one of the brain’s most important tools for keeping emotions steady as we age.

The research suggests that each night of restorative sleep gives the brain a chance to recalibrate stress and anxiety. When that deep sleep fades, emotional resilience may fade with it.