MALAYSIANS have elevated the art of not sleeping into something approaching a national identity, between the late-night mamak sessions, the group chats that never heard of a bedtime and the bosses who treat 11pm as perfectly reasonable hours for a voice note.
When the sniffles eventually arrive, the instinct is to blame the air-conditioning or the colleague who came to work sick. But what if the real culprit was simply that most Malaysians are not sleeping nearly enough? Does sleeping less than six hours a night actually make you more likely to catch a cold?
Verdict:
TRUE
The short answer is yes, and the numbers are more alarming than most people would expect.
A landmark study published in the peer-reviewed journal Sleep followed 164 healthy adults, tracked their actual sleep using wrist sensors for a week and then, in what must have been a deeply unpopular moment for participants, administered nasal drops containing the live cold virus directly up everyone's nose.
The researchers then sat back and watched to see who got sick.
People who slept less than six hours a night were 4.2 times more likely to catch the cold than those who managed more than seven hours.
Those who scraped by on less than five hours were 4.5 times more likely.
The lead researcher, Dr Aric Prather from the University of California San Francisco, noted that none of the other factors measured, including age, stress levels, income, race, education or smoking, came anywhere close to matching the predictive power of sleep.
"Sleep goes beyond all the other factors that were measured," Prather said.
"With all those things taken into account, statistically sleep still carried the day and was an overwhelmingly strong predictor for susceptibility to the cold virus."
Now consider what this means for Malaysians specifically.
A peer-reviewed study of 11,356 Malaysian working adults published in the journal Nature and Science of Sleep found that the average sleep duration among Malaysians was just 6.49 hours per night, with 54.7% sleeping less than the recommended seven hours regularly.
A separate Malaysian study using a standardised sleep quality assessment found the average was even lower among working adults in Kuala Lumpur, at just 5.95 hours per night, with 45% recording poor sleep quality overall.
The National Health and Morbidity Survey 2023 found that 38% of Malaysian adults were not getting enough sleep, with the problem worst among urban dwellers.
In other words, based on the cold study's findings, a significant proportion of Malaysians were walking around at somewhere between four and four and a half times the normal risk of catching a cold at any given moment, simply because of how little they slept.
The reason sleep had such a dramatic effect on cold susceptibility came down to what the immune system was actually doing during those lost hours.
During sleep, the body produced proteins called cytokines that acted as the immune system's internal communication network, coordinating the response to invading viruses and bacteria.
Cut sleep short and cytokine production dropped, leaving the immune system less organised and less ready to fight.
Sleep also played a critical role in keeping T cells, the immune system's frontline fighters against viruses, in peak condition.
Research from the University of Tübingen in Germany found that during sleep, stress hormone levels naturally fell, which allowed T cells to become stickier and more effective at latching onto and destroying virus-infected cells.
Stay up late, keep those stress hormones elevated and your T cells become sluggish and less effective.
A comprehensive review published in the journal Physiological Reviews confirmed that chronic insufficient sleep led to persistent low-grade inflammation throughout the body, which further weakened the immune system's ability to mount a proper defence when a virus showed up.
The good news was that the solution required no medication, no supplements and no expensive intervention.
It just required telling the group chat it would have to wait until morning, putting the phone down and going to sleep at a reasonable hour.
The body, the immune system and the nose would all be significantly better off for it.
Sources:
1. https://pmc.ncbi.nlm.nih.gov/
2. https://pubmed.ncbi.nlm.nih.
3. https://journals.physiology.
4. https://pmc.ncbi.nlm.nih.gov/
5. https://pmc.ncbi.nlm.nih.gov/
6. https://pmc.ncbi.nlm.nih.gov/
7. https://pmc.ncbi.nlm.nih.gov/
8. https://pubmed.ncbi.nlm.nih.
