Канадын судлаачид улирлын чанартай цагийн өөрчлөлтийг халж, стандарт цагийн хуваарийг байнгын болгох нь хүний эрүүл мэндэд илүү эерэг нөлөөтэй болохыг тогтоов.
British Columbia-ийн их сургуулийн сэтгэцийн эмч Raymond Lam болон Simon Fraser-ийн их сургуулийн нойр, циркадиан хэмнэл судлаач Ralph Mistlberger нарын тэргүүтэй баг нойр, сэтгэл санааны байдал, боловсрол, эдийн засгийн хүчин зүйлс болон биологийн хэмнэлийн талаарх судалгаануудыг нэгтгэн дүгнэжээ. Шинжилгээгээр зуны цагийн хуваарийг бүтэн жилийн турш мөрдөх нь өглөөний гэрлийг хязгаарлаж, хүний биологийн цаг болон ажлын хуваарийн зөрүүг нэмэгдүүлдэг болох нь тогтоогдсон байна. Тодруулбал, өглөөний гэрэл багасах нь нойрны хэмнэлийг хойшлуулж, улмаар нойрны дутагдал болон “нийгмийн тийрэлтэт хоцрогдол” (social jetlag) үүсэх эрсдэлтэй аж.
Судлаачид өвлийн улиралд тохиолддог улирлын чанартай сэтгэл гутралын нэг шалтгаан нь өглөөний гэрлийн дутагдалтай холбоотой гэж үздэг. Стандарт цагийг баримталснаар өглөөний гэрэлд илүү эрт хүрэх боломжтой бөгөөд энэ нь хүний биеийн дотоод цагийг зохицуулахад чухал үүрэг гүйцэтгэдэг байна. Ялангуяа өсвөр насныхан болон залуучуудын биеийн цаг нь байгалиасаа хойшлогдсон байдаг тул энэхүү өөрчлөлтөд илүү өртөмтгий байдаг аж.
АНУ-ын Төлөөлөгчдийн танхим 2026 оны долдугаар сарын 14-нд зуны цагийн хуваарийг байнгын болгох хуулийн төслийг баталсан боловч олон улсын туршлагаас үзэхэд энэ нь нойрны асуудал болон өвлийн өглөөний харанхуйтай холбоотой эрсдэлүүдийг дагуулдаг байна. Тухайлбал, 1974 онд АНУ, 2011 онд ОХУ тус тус зуны цагийг бүтэн жил мөрдөх туршилт хийж байсан ч сөрөг үр дагаврын улмаас буцаан цуцалж байжээ. Иймд эрдэмтэд стандарт цагийг сонгох нь зүйтэй бөгөөд хэрэв зуны цагийг сонгосон тохиолдолд ажил, хичээлийн цагийг хойшлуулах, өглөөний гэрэлтүүлгийг сайжруулах зэрэг арга хэмжээ авахыг зөвлөж байна.
Canadian Medical Association Journal-д нийтлэгдсэн энэхүү судалгаа нь ажиглалтын судалгаа болон газарзүйн байршлын харьцуулалтад үндэслэсэн тул урт хугацааны үр нөлөөний талаарх тодорхойгүй байдал хэвээр байгааг мэргэжилтнүүд онцолжээ.
Дэлгэрэнгүйг эх сурвалжаас харах
↓Эх сурвалжийг нээх ↓
Keeping the clocks on summer time all year means lighter evenings, but it also delays winter sunrise by an hour on the clock. People getting up early for work or school spend more of the morning in darkness.
A new Canadian analysis concludes that permanent standard time is the better choice for health if seasonal clock changes are abolished, because it preserves earlier access to morning light.
British Columbiaadopted permanent daylight saving time in March.Alberta and the Northwest Territorieshave also adopted year-round daylight saving time and will skip the November clock change. In the US, the Housepassed a bill to make daylight saving time permanenton July 14, and it wasreferred to a Senate committee the following day.
Psychiatrist Raymond Lam of the University of British Columbia and his colleagues assessed the health consequences of the two options: standard time, usually observed in winter, and daylight saving time, which runs an hour ahead.
Sleep and circadian rhythms researcher Ralph Mistlbergerof Simon Fraser University co-authored thepeer-reviewed analysis, which reviewed published research on biological rhythms, sleep, mood, education, and economic effects. The team also examined countries’ experiences with permanent time policies and compared sunrise and sunset times across Canadian cities.
In Toronto, the latest winter sunrise, in early January, would come at 7:51 am under permanent standard time and 8:51 am under permanent daylight saving time.
A Toronto resident waking at 7 am in early January would get up before sunrise under either setting, but daylight would arrive an hour sooner under standard time. Neither option changes the length of the day.
The brain’s main circadian clock coordinates sleep, alertness, and other daily functions. It needs daily adjustment to stay in step with the day. Morning light helps move it earlier, while evening light pushes it later.
“Imagine a wristwatch that runs 10 minutes slow each day, and every morning you make the 10 minute correction by setting it forward,” Mistlberger explained to ScienceAlert.
With less morning light, sleep rhythms can slip later while school and work still begin at the same hour. Getting up on time may mean cutting sleep short.
Social jetlag, the gap between the body clock and school or work schedules, has been linked to poorer physical and mental health, as has insufficient sleep. Seasonal clock changes can also disrupt sleep.
The analysis also draws on geographic comparisons: people living farther west within a time zone get later sunrises by the clock. Studies have linked this position with shorter sleep and some poorer health and economic outcomes, though these associations do not prove causation.
The researchers considered seasonal affective disorder, a form of depression often experienced in winter. One leading explanation involves the body clock slipping later when morning light is delayed. Morning bright-light therapy helps move it earlier; a later sunrise on the clock works in the opposite direction.
Teenagers and young adults may be especially vulnerable because their body clocks naturally shift later at that age.
“Later school and work times would help,” Mistlberger said. Brighter indoor lighting in the morning could also help, he added.
Several countries have tried year-round daylight saving time before.The US introduced it in 1974and abandoned it within the year, following concerns about dark winter mornings and children traveling to school before sunrise.Russia adopted it in 2011 and reversed it in 2014.
Permanent daylight saving time would keep evenings lighter, allowing more time for outdoor activity and socializing. Standard time brings earlier winter dusk, while early summer sunrise may wake some people too early. Latitude and location within time zones also determine how much the choice matters in a given place.
Much of the evidence comes from observational research and geographic comparisons, leaving uncertainty about permanent policies’ long-term health consequences.
The researchers recommend permanent standard time. If governments choose year-round daylight saving time, they advise considering later school and work starts, improving morning light exposure, and tracking whether sleep problems, winter depression, absenteeism, and road injuries rise.
The research has been published in Canadian Medical Association Journal.
This article was fact-checked by Fiona MacDonald and edited by Fiona MacDonald. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know.
