Scientists share how a cup of coffee can change the brain
New research has found that drinking just two cups of coffee after midday could be enough to shift the brain towards a more excitable and dynamic state during the night, wreaking havoc on your energy levels.
Canadian researchers said that caffeine - one of the most widely consumed stimulants in the world - can change the structure and complexity of brain activity during different stages of sleep.
Lead author of the study Professor Philipp Tholke said: 'The widespread use of caffeine among the public makes this topic an important health consideration.
'Understanding how caffeine affects sleep architecture and brain dynamics can help clarify its impact on neural health.'
The researchers, from the University of Montreal, analysed the sleep health of 40 healthy adults with moderate caffeine consumption aged 20 to 58.
Participants spent two nights at a sleep clinic one after ingesting 200mg of caffeine - approximately two cups of coffee - and another after having a placebo.
The researchers used a double-blind design so that they also did not know whether participants were coming into the clinic caffeinated or caffeine-free.
The participants' sleep quality was monitored using an electroencephalogram (EEG) which records brain activity by picking up electrical signals produced by the brain.
Using a sleep EEG, researchers focused on several markers of brain complexity looking at how random a brain signal is, how easily the signal can be compressed and how consistent a signal is over time.
They also looked at the distribution of electrical activity across different frequencies.
The results showed that caffeine mostly affected brain activity during non-REM sleep - the stage of the cycle which is considered the quiet or restful stage.
This stage is split into three distinct phases: a person falls asleep, and then moves from a light sleep into a deep sleep.
At this point a person's breathing, brain activity and heart rate typically slow down, body temperature drops and eye movement stops.
This is a very restorative phase helping the body repair tissue and muscle and strengthen the immune system.
However, researchers found that consuming caffeine after midday had a negative impact on this crucial stage, resulting in less restorative sleep.
'Caffeine delays but does not prevent sleep, so even though we can sleep under the influence of caffeine, the brain, and therefore also sleep, is impacted by the drug,' Prof Thölke told PsyPost.
'It leads to shallower sleep with increased information processing during the sleep stages where the brain normally enters deep restorative rest.'
The researchers also noted certain brain signals were flatter, suggesting that the under the influence of caffeine the brain more closely resembled a 'critical state' - where the brain is most responsive and adaptable.
They also analysed how age affected caffeine's impact on the brain and sleep health.
Generally, younger adults aged 20 to 27-years-old were more susceptible to caffeine's stimulant effects during rapid-eye-movement (REM) sleep compared to middle-aged adults.
Researchers theorized that this could be because older people have less adenosine receptors in the brain.
Adenosine is a chemical that builds up in the brain during waking hours eventually making us feel tired.
Caffeine works by blocking adenosine receptors, making us feel more awake.
The researchers suggested that because older adults have fewer receptors, the blocking effect of caffeine may not be so effective especially in REM sleep.
During non-REM sleep however the effects of caffeine were broadly the same across all age groups.
Researchers concluded therefore that caffeine has the ability to restructure the brain and impact how well we sleep.
However, they acknowledged that their study only included healthy individuals so concluded that the findings could not be extrapolated to individuals with neurological or psychiatric conditions like restless leg syndrome or Parkinson's.
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Reuters
2 hours ago
- Reuters
IQVIA beats quarterly estimates on resilient demand for healthcare analytics
July 22 (Reuters) - Contract research firm IQVIA Holdings (IQV.N), opens new tab posted second-quarter profit and revenue above Wall Street expectations on Tuesday, as demand rose for its healthcare data and analytics services, sending shares up around 8% in premarket trading. IQVIA's technology and analytics unit, which serves pharmaceutical and consumer health companies, benefited from higher drug approvals by the U.S. Food and Drug Administration. Still, the company narrowed its annual earnings forecast as drugmakers and biotech companies have been cancelling orders given to contract research firms, in response to the U.S. government's drug price negotiation program, proposed federal research budget cuts and potential tariffs. The Trump administration has been considering separate tariffs for the pharmaceutical industry, which could be as high as 200%. But analysts said that, overall, the quarterly results had "more pluses than minuses." "All-in, this print could have been worse and should clear a fairly low bar heading into the quarter," Leerink Partners analyst Michael Cherny said in a note. Quarterly sales at the technology and analytics unit was $1.63 billion, compared with estimates of $1.60 billion, according to data compiled by LSEG. IQVIA's total quarterly revenue rose 5.3% to $4.02 billion, beating analysts' average estimate of $3.96 billion. On an adjusted basis, it reported profit of $2.81 per share for the quarter ending June 30, above expectations of $2.77 per share. IQVIA now expects annual adjusted profit per share between $11.75 and $12.05, compared with $11.70 to $12.10 earlier. The Durham, North Carolina-based company also narrowed its annual revenue expectations to between $16.1 billion and $16.3 billion, from $16 billion to $16.4 billion earlier. The new forecast assumes a roughly $100 million COVID-related impact.
The Sun
2 hours ago
- The Sun
A spoonful of common diet staple an hour before bed ‘helps you sleep better' – plus 5 other hacks
STRUGGLING to get a decent night's sleep? Well, you aren't alone, Brits are one of the world's most sleep deprived countries - as we average just six and a half hours of kip per night, stats show. 3 Thankfully, a scoop of this everyday food might be the answer, and it's probably already in your cupboard. A doctor has claimed that scoffing a spoonful of peanut butter an hour before bed could help you sleep right through the night. 'This is because it contains tryptophan, an amino acid vital for the production of serotonin, which can have a calming effect on your brain,' said Dr Kunal Sood, US-based anaesthesiologist. It also packs healthy fats, which help keep your blood sugar stable, a key factor in preventing those annoying 3am wake-ups. 'Lastly, peanut butter also contains magnesium, which has been shown to also relax you and improve sleep quality,' Dr Sood explained in a recent TikTok video. Although there's no research on the effects of peanut butter on sleep specifically, some studies back the idea that tryptophan-rich foods can improve sleep. That's because tryptophan can be turned into a molecule called 5-HTP, which your body uses to make serotonin and melatonin. Serotonin helps regulate mood, thinking and sleep, while melatonin is the hormone that controls your sleep–wake cycle. But a 2024 study found peanut butter didn't help sleep. Although the research, published in the International Journal of Exercise Science, only tested 40 firefighters, who often have disrupted sleep anyway, so the results might not apply to everyone. Your ultimate sleep toolkit in 13 steps - from recording snoring to daylight hack Dr Sood was reacting to a viral video posted by 29-year-old Kat Eilonwy from Pennsylvania, US, which has now racked up 1.8million views. She said: 'So, apparently eating a spoon of peanut butter before bed helps drop your cortisol levels to help you sleep.' Cortisol, often called the 'stress hormone' can mess with your sleep if levels are too high in the evening. Previous research, including the 2021 ARISTOTLE study, has linked regular peanut butter consumption to lower cortisol levels, along with reduced anxiety and depression. Commenters were quick to back the nut butter hack. One wrote: 'I discovered that a spoonful before bedtime helps me sleep through the night.' 3 Another said: 'Every night I take one slice of bread, slap some PB on it and fold it in half. I'm always asleep within 30 minutes of eating that.' A third added: 'It works! I've been doing it for three months, doing it to help my stomach when I couldn't sleep and noticed I slept better after a spoonful of peanut butter.' Dr Sood's followers also agreed. One said: 'I have trouble sleeping almost every night. Peanut butter has helped me a lot.' Another added: 'Wow okay good reason to eat peanut butter.' And a third added: 'I thought I was the only one who did this!' Peanut butter, or just peanuts, has also been linked to a reduced risk of type 2 diabetes and bowel cancer. But Dr Sood warned: 'It is worth noting while peanut butter may help some people sleep, it is not for everyone.' As one unlucky commenter put it: 'Dammit, I'm allergic to peanuts.' 5 other sleeping hacks The NHS says we should all aim for seven to nine hours a night — but even the best sleepers struggle sometimes. For most of us, a proper night's kip feels like the ultimate prize. So how do you actually get it? Here are some well-known hacks which might be worth a try: 1. The military hack Used by soldiers to fall asleep in just 2 minutes, this technique involves relaxing your entire body step-by-step, starting with your face, then your shoulders, arms, and down to your legs. Clear your mind and take slow, deep breaths. It is meant to work, even if you're lying in a noisy room. 2. The melatonin boost Melatonin is the hormone your body makes to signal bedtime. You can help it along by dimming lights an hour before sleep and avoiding screens. In the UK, melatonin supplements aren't sold over the counter—you need a prescription to get them. 3. Cool down to nod off Your body needs to drop its core temperature to fall asleep easily. Which can be a bit of an issue in the summer. Keep your bedroom cool, around 18C is perfect, and use breathable bedding. Cooler temps help you drift off faster and get deeper sleep. 4. Cut caffeine after midday That afternoon cuppa might keep you wired when you should be winding down. At least eight hours should pass between your last hit of caffeine and bedtime. Try switching to decaf or herbal teas after lunch to avoid a late-night buzz. 5. Breathe and relax Try slow, deep breathing or a quick meditation before bed. It calms your mind and body, making it easier to switch off and drift off.
Daily Mail
2 hours ago
- Daily Mail
Forever chemicals linked to cancer and infertility now found in products used by 30million Americans
Nearly three in four reusable menstrual products contain traces of cancer-causing 'forever chemicals,' a new study suggests. Notre Dame researchers tested nearly 60 pairs of period underwear, pads and cups for PFAS (per- and polyfluoroalkyl substances), toxic chemicals that have been linked to cancer, infertility and birth defects. They earned the name because they don't break down in the body, instead leeching from nonstick cookware into food and cosmetic products into skin and building up in vital organs, increasing the risk of organ failure, reproductive complications and some forms of cancer. After analyzing over 300 samples taken from 59 reusable menstrual products, the researchers found 70 percent contained traces of PFAS, though they were low enough to suggest they were not added intentionally. Of those, 33 percent of period underwear and 25 percent of pads had the greatest rates of 'intentional fluorination,' meaning the chemicals were purposely added to wick moisture away and coat the surfaces. Because a majority of companies manufacturing reusable feminine hygiene products did not add PFAS intentionally, 'PFAS must not be essential' in creating them, the researchers said. The team believes PFAS in reusable period products can enter the body through direct contact with the skin and previous studies have suggested skin absorption could be a significant pathway to exposure to certain PFAS. The researchers hope the new study will discourage the use of PFAS in reusable feminine hygiene products like menstrual cups and underwear and increase ingredient transparency for one in five US women who use them. Graham Peaslee, study author and physicist at the University of Notre Dame, said: 'The reusable menstrual product market is a rapidly growing market, which relies heavily on the idea that these products are environmentally conscious because of the significant reduction in the use of paper and plastic products. 'To the extent that they use organic textiles, these products are also marketed to consumers who are typically health and environmentally conscious. However, we found that almost a third of them were being made with PFAS. 'This means these products are both a risk to the wearer as well as to the rest of us when they are eventually disposed of, since we know that these forever chemicals persist when they end up in landfills, contaminating irrigation and drinking water systems for all of us.' The new study builds on Peaslee's earlier research, which detected PFAS in period products, fast food wrappers and cosmetics. PFAS are thought to be endocrine-disrupting chemicals, meaning they imitate the body's hormones and interfere with the production of - and response to - natural hormones like estrogen and testosterone. This increases the risk of developing hormone-sensitive cancers like breast and ovarian cancer. The study, published Tuesday in the journal Environmental Science & Technology Letters, tested 59 reusable menstrual products manufactured in North America, South America, Europe and Asia-Pacific. These consisted of 43 pairs of period underwear, eight reusable pads, four menstrual cups, three pairs of reusable incontinence underwear and one reusable incontinence pad. Because these products have multiple layers, 323 samples were taken in total. Using particle-induced gamma-ray emission (PIGE) spectroscopy - which detects the presence of certain elements in surfaces - the team found 71 percent had PFAS concentrations low enough to be characterized as 'non-intentionally fluorinated,' meaning they were not purposely added. However, 33 percent of period underwear and 25 percent of reusable pads had 'intentional fluoridation,' suggesting PFAS was added on purpose. Even with the new study, Peaslee said: 'There's still a lot we don't know about the extent to which PFAS are being used in the manufacturing of these products, and too much we don't know about the potential for these chemicals to be absorbed through the skin by the consumers who wear them.' However, the results show because most products have low levels of PFAS, the chemicals 'must not be essential in the manufacture of reusable feminine hygiene products,' lead study author Alyssa Wicks, a graduate student at the University of Notre Dame, said. She added: 'This is good news in that it demonstrates PFAS are not required to produce these environmentally conscious products, and manufacturers should be able to make these textile products without chemicals of concern in them.'
