Nephrologist warns against waking up at 4 a.m. in middle age

Continuous sleep disruption in individuals over 50 not only stimulates the sympathetic nervous system, leading to chronic inflammation, but also directly damages the kidney's protective filtration membrane.

Many people over 50 develop a habit of waking up between 4 and 5 a.m. They often dismiss this as a natural sign of aging, paying little attention. However, Doctor Hung Yung-hsiang, a nephrologist with over 20 years of experience in Taiwan (China), warns that while the biological clock may shift earlier with age, waking up early, leading to chronic sleep deprivation, or continuous sleep disruption throughout the night, can increase the risk of kidney damage.

The American Society of Nephrology previously warned that for every 10% increase in sleep fragmentation, the glomerular filtration rate significantly decreases, and the risk of proteinuria surges by 28%.

In a post on his personal page on 15/10, Mr. Hung stated that older adults' tendency to wake up early is directly linked to the degeneration of the pineal gland in the brain. As this gland degenerates, the amount of melatonin hormone secreted sharply decreases and peaks earlier. Simultaneously, cortisol, a hormone that promotes alertness, also increases earlier in the morning.

This dual change shifts the biological clock of middle-aged and older adults forward, leading to habits of going to bed early and waking up early. Additionally, after age 50, sleep architecture primarily shifts to light sleep, making individuals susceptible to light, noise, or the urge to urinate. Even a gentle breeze or faint light can immediately awaken them.

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Analyzing the harms of fragmented sleep, Doctor Hung cited a 2017 study published in the journal of the American Society of Nephrology, which monitored the sleep of patients with chronic kidney disease. The results showed that for every 10% increase in sleep fragmentation, the glomerular filtration rate significantly declined, and the risk of proteinuria surged by 28%. Continuous waking and fragmented sleep quality keep the sympathetic nervous system constantly stimulated. Over time, this leads to chronic inflammation, damaging the kidney's filtration membrane.

Excessively short sleep duration also harms kidney health. The expert points out that if one starts sleeping between 9 and 10 p.m. and naturally wakes up between 4-5 a.m., ensuring 7 hours of sleep and feeling refreshed during the day, this is merely a normal and harmless shift in the biological clock. Conversely, if one starts sleeping past midnight but wakes up at 4 a.m., prolonged short sleep duration can lead to insulin resistance and a systemic inflammatory response.

For those who frequently wake up early due to age, the doctor recommends three effective methods to protect the kidneys:

First, calculate backward from your desired wake-up time to determine an appropriate bedtime. If you want to wake up at 5 a.m., ensure you are in deep sleep before 10 p.m. to maintain a minimum of 7 hours of sleep each night.

Second, expose yourself to moderate sunlight during the day and reduce indoor lighting in the evening to stabilize your biological rhythm. After waking up, avoid lingering in bed scrolling on your phone or using snooze alarms to try to sleep further.

Furthermore, if you frequently experience nocturia, loud snoring, or suspect you have sleep apnea, you should seek medical attention promptly to identify the cause and receive timely treatment.