午夜剧场

In modern society, it is said that one in five people suffers from insomnia, and one in 20 takes sleeping pills. The prevalence of insomnia is said to increase particularly with age, and in our country's rapidly aging society, sleep disorders among the elderly are on a continuous upward trend.

According to the summary of the 2015 National Health and Nutrition Survey by the Ministry of Health, Labour and Welfare, the percentage of people sleeping seven hours or more is 18.3% for men and 14.4% for women aged 50–59. For those aged 70 and over, these figures rise to 47.6% for men and 39.2% for women, representing an increase of 2.6 times for men and 2.7 times for women. Furthermore, a 2010 survey on psychotropic drug prescriptions using the Ministry's medical fee data showed that the prescription rate for sleeping pills is 3.6% for men and 5.2% for women aged 55–59. However, for those aged 65 and over, it rises to 7.6% for men and 10.6% for women, doubling the prescription rate for both genders.

This rapid increase in sleeping pill prescription rates is not seen in age groups under 60. It is specific to sleeping pills and anti-anxiety medications; such a trend is not observed for antidepressants or other psychotropic drugs. While the causal relationship has not been investigated in detail, it is possible that upon reaching retirement age at 60–65, people are able to secure sufficient sleep time at home, leading to a sudden extension of sleep duration. In actual clinical settings, we often see cases where insomnia occurs because people spend more time at home after retirement, reducing mental and physical burdens. This lifestyle, lacking excessive fatigue, leads to longer sleep times and shorter waking hours, which in turn reduces the physiological drive for sleep.

On the other hand, under my supervision, we used wrist-worn sleep monitors to analyze the relationship between sleep duration and BMI (Body Mass Index). This study revealed the "optimal sleep duration for weight loss" (Figure). The results showed that based on the relationship between sleep duration and BMI values, individuals with "seven hours of sleep" had the lowest average BMI. To maintain a body that loses weight easily, sleep duration should be neither too short nor too long; seven hours was found to be the best duration.

When averaging BMI values by sleep duration, men sleeping "7 hours" or "7 hours 30 minutes" and women sleeping "7 hours" had the lowest BMI values. Meanwhile, looking at the number of people per sleep duration category, "6 hours" was most common for men and "6 hours 30 minutes" for women. From those peaks, the number of people gradually decreased as sleep became longer or shorter. To achieve sleep that facilitates weight loss, it was found that men should aim for an extra hour and women an extra 30 minutes of sleep.

According to several large-scale surveys conducted in the US and Japan, people who sleep seven hours have the highest probability of being alive six years later. Japanese people often go to extremes in everything; as a result of work-style reforms, there is a possibility of shifting from "extreme overworking" to "extreme over-resting."

From these results, the key for the retired senior generation to suppress the use of sleeping pills is not to exceed seven hours of sleep. For the working generation who wish to prevent obesity—a cause of lifestyle-related diseases—it is important to secure seven hours of sleep as much as possible. Rather than believing in extreme sleep management, please remember that "seven hours is the benchmark for good sleep."

When I opened the Sleep Clinic in Chofu 14 years ago, patients flooded in from all over the country. We expanded to Ginza, Aoyama, and Sapporo, and also opened a sleep clinic within 午夜剧场 Hospital in Shinanomachi. The reason patients flock to us is the "actigraph" I developed. By simply wearing this device—about the size of a 500-yen coin—on the waist, one can track daytime activity levels, calories burned, timing of falling asleep, sleep quality, posture, and even tossing and turning. Moderate daytime activity is also essential for good sleep, and this can be easily monitored with the actigraph.