Many seniors fret over their difficulty in falling asleep at night.
The older we get, the less time we seem to be able to sleep - the average is just six hours for 65-year-olds.
When we try harder to sleep, our sleep tends to become lighter and we wake up more frequently.
Last year, the Health, Labor and Welfare Ministry revised its "sleep guidelines," which are designed to help people get the sleep they need for a healthy lifestyle.
It was the first revision made since 2003. Packed with scientific insight on sleep, the guidelines include different words of warning for every age group.
Until the early teens, most people can get over eight hours of sleep each night.
This gradually drops once we hit 20, and by the time we're 65 we end up sleeping around six hours a night.
We require less sleep for a variety of reasons, such as reduced basal metabolism - the energy we need to keep alive - and the amount of exercise we get.
On the other hand, the time spent in bed starts going up after we turn 45, climbing past 7½ hours a night by the time we turn 75.
"Unnecessarily lengthening your time in bed only makes you sleep lighter," the guidelines say.
They also warn: "It becomes easier to wake up in the middle of the night, and harder to feel like you got a good night's sleep. It's important to regulate the times you go to bed and wake up, and you should design an appropriate sleep schedule for yourself."
So how does one go about making sure they have a good night's sleep?
Kazuo Mishima, a doctor at the National Center of Neurology and Psychiatry in Tokyo, recommends keeping a "sleep diary."
Recording the times you go to bed, turning off the lights after reading a book, when you get out of bed, and how long you could not sleep will help you understand exactly how much sleep you're getting, he said.
As for the time it takes from turning off the lights to falling asleep, feel free to give a ballpark figure.
The same goes for the time between waking up once at night and falling back to sleep.
Keeping a diary every day for a week will reveal your average hours of sleep in proportion to hours spent in bed.
"Those for whom the proportion is less than 85 per cent should try delaying their bedtime or getting out of bed when they can't sleep, to narrow the difference," Mishima said.
For example, if you usually sleep six hours, and the time you go to sleep and waking up at night is 30 minutes to one hour, you should go to bed at 11 p.m. and wake up at 6 a.m.
Those suffering from insomnia should visit a clinic and get advice from a sleep specialist.
Avoid nightcaps since they make your sleep lighter, and try not to fall into the "nap trap" - one hour of daytime napping is said to equal two or three hours of nighttime sleep.
"If you have to give in to drowsiness," Mishima said, "try to nap between 1 p.m. and 3 p.m. which has little impact on your nighttime sleep."
"Set an alarm to ensure you don't sleep longer than half an hour. That way, you won't enter a deep sleep," he said.
Hideki Tanaka, a professor of psychology at Hiroshima Kokusai Gakuin University, recommends light exercise in the early evening.
"Take a walk, stretch and try abdominal breathing around 5 o'clock in the evening," Tanaka said.
Taking a catnap in the evening means it will be more difficult to fall asleep at night, so exercise is a great way to stay awake.
Keep it light, though, since intense exercise will only make you sleepy immediately afterward.
For abdominal breathing, place both hands on your belly, drawing breaths slowly through your nose as you expand your abdomen. Pucker your lips and slowly exhale, deflating your abdomen. Repeat three times.
"You can even do abdominal breathing right before going to sleep," Tanaka said. "It helps relieve the stress that keeps you awake at night."
Points for better sleep
- Seniors sleep an average of six hours a night. When you try to sleep longer, your sleep becomes lighter and you won't feel like you got a good night's rest
- Keep a sleep diary, and try to limit "time spent in bed" compared to "time slept"
- Limit naps to 30 minutes, and aim for between 1 p.m. and 3 p.m.
- Fight off drowsiness in the early evening with light exercise and abdominal breathing