As we were told by Dr. Sergey Kolomeychuk, Senior Researcher at the Genetics Laboratory of the Institute of Biology KarRC RAS, scientists in this study investigated how the intensity of light flux impacts blood lipid composition and the risks of developing cardiovascular diseases. It is worth noting that changes in light flux intensity entail changes in the levels of ‘good’ and ‘bad’ cholesterol in the blood.
The research has resulted in few other conclusions. Scientists advocate the importance of regulating light exposure: maximum levels in the morning and total darkness at night. Furthermore, combining light hygiene with physical activity is beneficial for human vital functions. This combination reduces ‘bad’ cholesterol levels, while augmenting ‘good’ cholesterol. Ultimately, these factors can be drivers of life expectancy.
The factors investigated included daylight duration, the timing of light exposure, and the impact of artificial lighting, which is indispensable in northern, Arctic regions. It was found that when artificial light becomes dominant, especially when coupled with a lack of physical activity, it can have a detrimental effect on human health.
The research employed a set of modern methods permitting to assess the light flux, physical activity, sleep, biochemistry, and the activity of the genes that control our circadian rhythms. The study showed that both insufficient and excessive sleep can be harmful to humans.
The motivation for the collaboration between Karelian scientists and colleagues from other research institutions was the opportunity to apply different methods. Here, at the Institute of Biology KarRC RAS, genetic methods were used; Tyumen State Medical University employed methods for recording circadian rhythm activity; and scientists from Syktyvkar developed and worked with questionnaires on eating behavior. The combination of various methods and approaches has enabled the team to achieve excellent results.
March 13th is World Sleep Day. Curiously, just before this day, several media reported that Petrozavodsk is among the top three Russian cities whose residents have the so-called "insomnia gene," meaning they are predisposed to sleep problems. In the reported study, this gene was found in one in eight Petrozavodsk residents. The number was higher only in Magnitogorsk and Makhachkala. We asked Sergey Kolomeychuk to comment on the results of this study as well.
As Sergey Nikolaevich explained, insomnia is not caused by a single gene disorder, but by a combined activity and interaction of dozens or even hundreds of genes. Hence, it is premature to draw far-reaching conclusions based on the presence or high frequency of just one gene. Or else, were presented only partial information about that study, which was much more comprehensive, and which needs to be double-checked from the perspectives of physiology, genetics, and statistics.
There are several more factors that don’t let us assess the research results in a definite way. The age cohort studied matters a lot, since gene activity changes with age. The season during which the study was conducted also affects the results because, as a rule, insomnia is linked to the amount of light that reaches the human retina. Other weighty factors to consider are the family history, social activity -- like bedtime habits and work schedules. Smoking, alcohol or chemicals abuse, or a high-fat diet could be another factor for the functioning of our biological clock and the sleep-wake cycle.
Insomnia is an aggregate of problems, encompassing difficulty falling asleep, intermittent sleep, and waking up too early. As a result, a person cannot recover to full capacity during sleep, which lowers the quality of their life. The mentioned publication does not say whether the presence of this gene variant was compared between native residents and newcomers, or whether comparisons were made between groups of healthy individuals and those with this specific disorder – insomnia, i.e. we do not know how the sample was formed for that study.
In our region, sleep problems can worsen with the onset of the White Nights period. This is not about genetics, but about excessive light. Blackout curtains can help reduce the impact, - explained Sergey Kolomeychuk.
- I wouldn't jump to conclusions myself, and I would warn people of Petrozavodsk against making any hasty, far-reaching conclusions either. This is, indeed, a scientific result, but complete information is necessary to comprehend its implications. For now, the result only indicates that 13 out of 100 residents of Petrozavodsk carry this gene variant, -- said Sergey Kolomeychuk.