Why sleep decline matters in aging
Older adults frequently struggle with fragmented or shortened sleep. Research shows that age reduces total sleep time, lowers the proportion of restorative REM and slow-wave sleep, and increases the number of arousals during the night.
These changes aren't just an inconvenience. Poor sleep undermines memory consolidation, accelerates cognitive decline, and may contribute to the buildup of toxic proteins linked to dementias like Alzheimer's disease.
Interventions that can stabilize or restore sleep patterns therefore represent a promising way to protect brain health in aging. Yet so far, few treatments have successfully targeted age-related sleep disruption without significant side effects.
Centella asiatica: an ancient herb with modern promise
Centella asiatica, also known as Gotu Kola, is a medicinal plant used for centuries in Ayurvedic and traditional Chinese medicine. Modern research has highlighted its neuroprotective and cognitive-enhancing properties in both humans and animal models. Extracts from the plant have been tested in contexts ranging from healthy aging to neurodegenerative diseases.
Despite its reputation, little was known about whether the herb could specifically influence sleep patterns. The new study, led by researchers at the University of Minnesota and published in Frontiers in Aging Neuroscience, set out to test that question directly.
The study: testing Centella on aged mice
Researchers fed male and female C57BL/6J mice - 18 months old, roughly equivalent to senior humans - with food containing a water extract of Centella asiatica (CAW) at a dose of 1000 mg/kg per day. Control mice received identical chow without the extract.
To measure sleep, the team implanted electrodes to record EEG and EMG signals, capturing both brain activity and muscle tone. This allowed precise tracking of sleep stages: wake, non-REM, and REM sleep.
Results: better REM sleep and fewer arousals
The findings showed a moderate but measurable benefit of Centella supplementation:
- In aged male mice, CAW increased the duration of REM sleep and enhanced theta power (a brain rhythm linked to memory processing) during REM.
- In aged female mice, CAW did not extend REM but reduced the number of arousals during sleep, stabilizing overall sleep architecture.
- In both sexes, the improvements suggested that the herb helped counter some hallmarks of age-related sleep decline.
The results were also sex-dependent, echoing broader findings in neuroscience that male and female brains can respond differently to both aging and treatments.
Why REM matters
REM sleep is especially critical for memory consolidation, learning, and emotional regulation. Reductions in REM are strongly linked to cognitive decline in aging and to greater risk for Alzheimer's disease.
By increasing REM sleep and boosting its quality (through higher theta power), Centella may support the neural processes that protect memory and cognition. Similarly, reducing sleep fragmentation in females could help stabilize circadian rhythms and restore the continuity of rest.
A step toward natural interventions
While the effects observed were moderate, they are meaningful. Few safe interventions exist for age-related sleep disruption. Prescription sleep medications often carry risks of dependence, falls, or next-day drowsiness.
Botanical extracts like Centella asiatica may represent a gentler approach, improving brain physiology without heavy sedation. If replicated in humans, such treatments could enhance quality of life for older adults and potentially delay the progression of neurodegenerative conditions.
What comes next
The study authors emphasize that their work is preclinical. Results in mice do not always translate directly to humans, and larger trials will be needed. Future research will need to:
- Test whether similar benefits occur in older human adults.
- Examine long-term cognitive outcomes, not just sleep patterns.
- Clarify the active compounds in Centella responsible for the effects.
- Explore why males and females respond differently.
Still, the study adds to a growing body of evidence that plant-derived compounds can play a role in supporting brain health and longevity.
Seven Reflections view
Sleep is not just downtime - it is the maintenance cycle of the mind. When aging disrupts this cycle, memory, mood, and resilience all begin to erode.
The idea that a simple plant extract could strengthen this nightly renewal process is compelling. Centella asiatica has traveled from ancient healing traditions into modern neuroscience labs, where its subtle but significant effects on sleep may signal a new path for natural interventions.
If future studies confirm the promise seen in mice, the herb may become part of a broader toolkit to help humans age not just longer, but clearer and more rested.
