From gangrene to deadly liver damage – the 92 conditions linked to going to bed after a specific time

The Sun

30-07-2025

GOING to sleep past a specific time could up the risk of 92 conditions, scientists have suggested.
This includes gangrene, liver damage, Parkinson's disease and type 2 diabetes, according to Chinese researchers.
It's no secret that persistent poor sleep can impact your health, with studies showing it may increase the likelihood of developing dementia, heart disease, diabetes, obesity and even cancer.
But much of this research focuses on sleep duration – how many hours of kip participants get a night – rather than factors like bedtime and how well people sleep through the night.
Now, scientists from Peking University and Army Medical University say going to sleep past 12:30am may increase the risk of ill health.
"Evidence suggests that sleep traits might be associated with a number of diseases affecting diverse systems, such as cardiovascular diseases, metabolic disorders, and mental diseases," researchers wrote in Health Data Science.
"However, in most publications to date, sleep has been measured by subjective recall of the participants, which has been found to bear systematic error in some aspects and may lead to misunderstanding of sleep's health impact.
"Furthermore, the available literature has mainly focused on certain sleep traits, namely, sleep duration, while other traits such as sleep timing and sleep rhythm have less often been analysed."
They said sleep regularity - such as going to bed at a consistent time and having stable circadian rhythms - is a little known but critical factor in disease risk.
Researchers used data from 88,461 adults who took part in the UK Biobank study.
Participants wore small sensors called accelerometers, which collected data on their bedtime, how long they slept a night and whether they woke up, for an average of about seven years.
Scientists paired this information with data from NHS records, cancer registries and the National Death Index.
I spent three days at a sleep retreat - these are the top 7 things I learnt
They found that sleep habits picked up through the accelerometers played a significant role in the risk of developing certain diseases.
Researchers studied 172 diseases.
Researchers found that poor sleep habits can double the risk of certain diseases.
For example, participants with the most irregular sleep patterns had more than double the risk of gangrene compared to those with consistent sleep routines
Meanwhile, people who went to sleep after 12:30am had over double the risk of liver problems such as fibrosis and cirrhosis, compared to those who went to bed between 11:00 and 11:30 pm.
For 92 diseases, at least 20 per cent of the risk was due to sleep traits and for 44 diseases, more than 30 per cent of the risk was linked to sleep factors.
Examples included:
Parkinson's disease, where the risk was linked to how consistent sleep was each day.
Heart disease, where the risk was tied to balance between activity and rest.
Type 2 diabetes, where the risk was linked to regular sleep timing.
Obesity, where the risk was tied to balance between activity and rest.
Overactive thyroid, where bedtime played a role.
Urinary incontinence, where risk was linked to sleep quality.
How bad sleep affects weight
Previously in The Sun, experts explained how sleep is closely linked with weight.
Disrupts hunger hormones
Ghrelin is a hormone released after the brain signals the stomach is empty, while leptin is released from fat cells to suppress hunger - and tell the brain it's full.
Studies have shown that when you don't get enough shut-eye, the body makes more ghrelin and less leptin - leaving you more hungry.
One study of 12 men led by University of Chicago showed two days of sleep deprivation drove leptin levels in the blood down by 18 per cent, while increasing ghrelin by 28 per cent.
The men reported a 24 per cent increase in their hunger and appetite compared to when they were given two restful nights.
More time to eat
The less you are asleep, the more you are awake. This gives more of an opportunity to eat.
In the modern day world, people are awake for up to 17 hours at a time - 7am till 12pm. It leaves a huge window for being awake and eating.
If you're struggling with both your weight and sleep, try finishing your meals three to four hours before bed time. That might mean limiting your eating window from 9am until 6pm.
Reach for takeaways
If you have a weird sleeping pattern, chances are your eating schedule is also off-whack.
Struggling to sleep can see us turn to convenience - takeaways, ready meals, oven foods and more, whi;e being energised gives us more motivation to cook healthily.
Eat more calories than normal
Studies suggest that the less sleep you get, the more calorie-dense food you choose to eat.
One study in Chicago found that men ate more food at a buffet after four consecutive night's of rough sleep compared with when they were rested.
They consumed around 340 calories more, mostly because they ate more snacks and carbohydrate-rich food.
Researchers from King's College London also found that adults consumed an additional 385 calories – the equivalent of one and a half Mars Bars – on days after they were deprived of kip by combining the results of 11 previous studies.
More desire for food
Foods, especially those high in calories, are more appetising when we are sleep deprived because we subconsciously know they will boost our energy.
A German study showed the lengths sleepy people would go to for calorific snacks using 32 healthy men.
After a normal dinner and either a restful or restless night's sleep, the men were given three Euros to spend on snacks and told to bid the maximum amount they were willing to spend on each item.
When sleep deprived. participants were willing to pay extra for the junk food items - which they were allowed to eat afterwards - suggesting a stronger desire.
Fat storage more likely
Scientists have warned that not getting enough sleep changes how the body deals with food, which could then lead to weight gain.
One study showed that men who ate a large bowl of chilli mac and cheese after four nights of bad sleep reacted differently to the food than those who were well-rested.
Researchers at Pennsylvania State University said blood tests showed lipids (fats) from foods were cleared faster, suggesting they were being stored almost instantly.
The process did not spring back to its normal rate even after the men were given a long night's sleep.
The study also challenged previous claims that sleeping over nine hours each night is harmful.
Previous research has suggested "long sleepers" could be at higher risk of stroke and heart disease.
Researchers said "misclassification" may be to blame, as 21 per cent of 'long sleepers' actually slept less than six hours, suggesting that time spent in bed is often confused with actual sleep time.
Prof Shengfeng Wang, senior author of the study, said: 'Our findings underscore the overlooked importance of sleep regularity.
'It's time we broaden our definition of good sleep beyond just duration.'
The study team suggested that inflammation could be upping the risk of disease in people who sleep poorly, as disrupted sleep might trigger immune responses that contribute to illness.
Researchers concluded: "Our results may suggest that the various dimensions of sleep traits deserve more attention in future studies and that pursuing comprehensive control of sleep traits may have greater benefit for health over merely ensuring adequate sleep duration."
Fortunately, there are easy things we can do to correct some – if not all – our poor sleep habits, they suggested.
"For example, the disruption of sleep rhythm can be substantially improved if the unhealthy habit of social media use before sleep (so-called Twitter jetlag) can be corrected," they said.
Next, the team will look into whether sleep improvements can reduce the risk of disease over time.
The best sleep routine and environment
Thomas Høegh Reisenhus, TEMPUR® sleep specialist & sleep counsellor, reveals the key components of a good bedtime routine and environment...
A sure-fire way to facilitate a better night's sleep is to practice good sleep hygiene.
Establish a sleep routine that works for you and stick to it.
This will help your body establish a consistent, natural sleep-wake cycle which can do wonders for your overall sleep quality.
As such, try to avoid making up for lost sleep with a lie-in.
Instead of sleeping in, spend your morning reading a book in bed or having a leisurely coffee in the kitchen.
Ensure that your bedroom, bedding, and sleepwear are fit for purpose too.
The ideal sleep environment is dark, quiet, and cool – much like a cave.
If you find unwelcome sources of light are keeping you up, consider investing in an eye mask or black-out curtains.
Adding soft furnishings can be a great way to reduce noise, with the surfaces having an absorptive quality, but if this doesn't work, consider embracing a soothing soundtrack to block it out.
In terms of temperature, try to keep your bedroom at 18°C. You can further reduce the risk of waking up due to overheating by ensuring that all your bedding and sleepwear is made with natural, breathable materials such as cotton and linen.
Bear in mind that everyone is different; what might work for most, may not work for you!
Whilst knowing how much sleep you should get, how to overcome common barriers, and practicing good sleep hygiene can facilitate a great night's sleep, if you continue to struggle with sleep or fatigue persistently, do not hesitate to visit a doctor or health professional for support.