In the research, the scientist focused on a hormone melatonin, which affects the way our biological functions differentiate between day and night.
"As we age, the melatonin hormone signal weakens," said Prof. Zisapel.
"As a result, our bodies and brains feel less difference between day and night," she added.
Zisapel said that exacerbating the effect of low melatonin levels, aging people tend to sleep in a less organized fashion than younger people.
"People are sleeping in front of the TV, or nodding off during conversations, and taking long afternoon naps. This leads to less sleep at night. In a way, their sleep habits become more like babies', and less like those of healthy adults who sleep in consolidated periods during the night," Zisapel said.
Mimicking the profile of night-time melatonin found in our bodies, Circadin replenishes the much-needed hormone, which declines steadily with age.
The clinical trials showed that Circadin improved sleep quality and morning alertness, and helps those 55 and over get a better night's sleep.
The new drug therapy "improves sleep and daytime vigilance, helping to re-organize the circadian system, the body's internal clock," said Prof. Zisapel.
The study appears in the Journal of Sleep Research.