Why Do We Wake Up Earlier As We Age According to Experts
Like other parts of our physical and mental health, our brain’s responsiveness reduces as we age.
According to the director of the Center for Sleep and Circadian Sciences at the University of Arizona Health Sciences, Dr. Sairam Parthasarathy, the brain’s wiring is probably not sensing and responding to the inputs as well as it previously did because it’s aging.
These inputs are sunlight, sunset, meals, physical activity, social cues, etc. Dr. Parthasarathy explains that they refer to these inputs as time givers because they give time to the brain or help it sense where it is in the 24-hour circadian cycle.
For example, in a younger person, dinner time may help their brain understand that bedtime is in a couple of hours. On the other hand, this connection may not occur in an older person.
The nerves that give our brain time cues undergo the same level of degeneration that the brain does. This inability to sense time cues is one of the reasons why older people become tired before their kids or grandkids. So, this means they’ll wake up fully rested and earlier than them.
Lustig also notes that the earlier waking up may also have to do with the vision changes that come with age. Namely, they lower the intensity of the degree of light stimulation that the brain gets. This is important for setting the circadian clock and ensuring it works optimally.
This is particularly the case for people who have cataracts, a common eye condition that affects more than 50 percent of Americans aged 80 and up, according to the NIH. This condition is linked with double vision, blurry vision, and poor eyesight.
With cataracts, the evening light doesn’t go into the eyes so the sunset is earlier for the brain than when it sets. As there’s less light in the eyes due to cataract issues, the body releases melatonin, a sleep hormone, earlier.
On the other hand, the melatonin begins to increase after sunset in younger people. In people with cataracts whose brains think that the sunset is earlier than it is, they become tired sooner in the evening, go to bed sooner, and wake up sooner.
Lustig notes that a cataract removal surgery may help better sleep quality and sleep duration by improving the light cues.
