Sleeping Patterns Change over Time
People who catch less than seven hours of zzz's per night may be more susceptible to weight gain and illnesses.
As people age, they may find themselves frequently waking during the night when they really want to sleep. This may be in part due to our ancestral sleeping patterns. Before the advent of modern technology, when there were few sources of artificial lighting, people would devote up to 14 hours to sleep each night during the winter. They experienced two bouts of concentrated sleep; the first was called "dead" sleep which lasted a few hours and then led to a wakeful, meditative time for two hours in the middle of the night. They would then return to sleep and experience the "morning" sleep phase. An experiment conducted in a sleep study lab in the United States simulated this winter sleep cycle with participants, and positive results were reported. Many people enjoyed the wakeful phase in the middle of the night, calling it "a quiescent meditative state" and claimed it led to a sort of "midnight comfort."
To our high-strung overworked culture, devoting 12 hours to sleep may seem ridiculous, so we have concentrated our sleep time into one long six to eight hour period. As more people are aging, they find that their peace in sleep becomes more fragile, and so have a hard time staying asleep in our not so natural method of catching eight straight hours. This is due to changing brain waves - when we are young, waves that are high and slow provide the most restorative sleep, and as we age, the peaks mellow out and don't protect us as well from disturbances like snoring partners and barking dogs.
If you are finding your sleep is being disturbed, there are several ways you can alleviate this. For older people who are retired and on a more relaxed schedule, they can try to devote more time to rest. The siesta model with naps in the afternoon is another possibility. If you do have to work all day, then modifying the consolidated sleep model to tightly restricting the number of hours in bed can hopefully produce more efficient sleep, with the aim being to place yourself in bed to sleep, not catch up on other obligations. The target would be to find a sleep pattern that works for you and stick with it. Different people need a different number of hours of sleep per night, but studies show that people who catch less than seven hours of zzz's per night may be more susceptible to weight gain and illnesses like the common cold.