Aging brains store less
Older people often say time seems to pass faster than it used to. A new theory links this to a concrete mechanism: the energy deficit in aging cells.
We remember more when we are young. Not because our youth was more eventful, but because the brain had more energy to encode and store memories. As that capacity declines, fewer moments are stored per unit of time. When looking back, that period feels more compressed than it actually was. The researchers developing this theory draw on studies suggesting people retain around 2 percent of their experiences.
As the brain becomes less efficient, that percentage drops further. Fewer memories across a given period make that period feel shorter in retrospect. The theory argues this is not purely psychological but is connected to reduced energy production (ATP synthesis) in aging brain cells.
Energy as a link between cell and consciousness
Brain cells are exceptionally energy-hungry. They consume a disproportionate share of the body’s total energy output. When mitochondria, the structures in cells that generate energy, function less effectively, the capacity to form new connections and consolidate memories decreases.
The theory is speculative, but consistent with known facts. Aging brains do show less efficient energy production. Studies on memory performance in older adults confirm that both storage and retrieval of memories slow down.
Implications for aging research
If the perception of time is partly a function of energy capacity in the brain, then improving that capacity might also have a subjective effect. Interventions supporting mitochondrial function are already being explored in the context of cognitive aging. This theory adds another dimension: not only cognitive performance, but also the lived experience of time might be affected.
The idea needs further testing. But it connects cellular biology to one of the most universal human experiences of growing older.
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