When we think of carcinogens, terms like “tobacco,” “alcohol,” and “radiation” often come to mind. Surprisingly, few associate “upside-down day-night cycles” with cancer risk. The notion of “staying up late causing cancer” is something we frequently hear about, and it’s not uncommon to see individuals cautioning others against it following a cancer diagnosis. In February 2024, a study published in the Journal of Hepatology provided experimental evidence for the first time that chronic circadian rhythm disruption, or “upside-down biology,” is indeed a human carcinogen.
The circadian rhythm, also known as the “biological clock,” is a 24-hour internal clock in our brains. It synchronizes with the Earth’s day-night cycle to regulate the periodicity of sleep, wakefulness, and nearly all other bodily functions. When this internal “clock” is disrupted, many diseases, including cancer, may ensue.
Research teams, using mice with physiological rhythms similar to humans, discovered that tumors developed spontaneously under conditions of disrupted circadian rhythms (chronic circadian rhythm disorder). When the mice were returned to a normal day-night cycle, tumor growth slowed, metastasis was inhibited, and their gene expression patterns reverted to their previous state.
In addition to upside-down day-night cycles, these sleep habits can also increase the risk of cancer:
1. People who sleep less than 6 hours have a 41% higher risk of cancer.
Compared to those who sleep between 6-8 hours at night, individuals sleeping less than 6 hours have a 41% increased risk of cancer. Among female participants, the related risk is even higher, at 53%.
2. People who never nap have a significantly higher risk of cancer.
Compared to those who nap for more than 60 minutes, participants who never nap have a 60% increased risk of cancer.
3. Those who sleep less than 6 hours at night and never nap have a high risk of cancer.
Compared to participants who sleep 6-8 hours at night and nap for more than 60 minutes, those who sleep less than 6 hours at night and never nap have an 82% increased risk of cancer.
Therefore, if you sleep less than 6 hours at night and do not nap during the day, such sleep patterns make you more prone to cancer.
Eight things you should never do before bedtime:
1. Do not go to bed too late.
Many people have experienced staying up late; the urge to sleep is strong around 10-11 PM, but after browsing on a phone or watching TV, sleep eludes them by 2-3 AM. The hours between 11 PM and 3 AM are prime time for entering deep sleep, and once missed, the benefits of sleep cannot be fully regained.
2. Avoid intense exercise before bed.
Nighttime workouts or running may overstimulate the brain, disrupting regular sleep patterns.
“Exercising during the day increases fatigue, which in turn promotes sleep, making it relatively easier at night.” To improve sleep, exercise should be done during the day rather than at night, when it can lead to excessive brain stimulation and hinder sleep onset.
3. Do not eat too much before bed.
Consuming heavy meals or late-night snacks can affect sleep. Eating too much before bed can raise blood sugar levels, leading to increased excitement and difficulty falling asleep. If hungry before bed, avoid high-sugar and high-carb foods and opt for a cup of warm milk instead.
4. Do not talk excessively before bed.
Chatting or making long phone calls before bed can excite the brain, making it difficult to fall asleep. Moreover, post-conversation rumination can further prevent restful sleep.
5. Avoid overthinking before bed.
Often, individuals use the evening to complete unfinished tasks, especially mentally demanding work. Overthinking before bed keeps the brain in a state of excitement, making it hard to fall asleep despite being in bed.
6. Refrain from using smartphones before bed.
Using smartphones or scrolling through short videos before bed has become a routine for many. However, it often leads to lying in bed awake for an hour or more. Smartphone use not only delays sleep onset but can also make it harder to fall asleep afterward.
7. Avoid emotional excitement before bed.
Arguing with family or friends before bed can lead to poor sleep quality or insomnia. Strong emotions can stimulate or disrupt the nervous system, making it difficult to fall asleep. Therefore, maintain calm emotions before bedtime.
8. Avoid drinking strong tea or coffee before bed.
Many know that beverages containing caffeine, like strong tea or coffee, can cause sleeplessness. Similarly, it is best to avoid caffeinated drinks like some milk teas within 3-4 hours before bed, as they can lead to pre-sleep agitation and disrupt regular sleep patterns.
In conclusion, maintaining a regular sleep schedule and healthy sleep habits are crucial for reducing cancer risk. It’s essential to prioritize sleep and create a relaxing bedtime routine to promote better health and well-being.
