Latest news with #TimothyHearn
1News
07-07-2025
- Health
- 1News
Why frequent nightmares may shorten your life by years
Australian expert Timothy Hearn explains why frequent nightmares can create faster aging and poor health. Waking up from a nightmare can leave your heart pounding, but the effects may reach far beyond a restless night. Adults who suffer bad dreams every week were almost three times more likely to die before age 75 than people who rarely have them. This alarming conclusion – which is yet to be peer reviewed – comes from researchers who combined data from four large long-term studies in the US, following more than 4000 people between the ages of 26 and 74. At the beginning, participants reported how often nightmares disrupted their sleep. Over the next 18 years, the researchers kept track of how many participants died prematurely – 227 in total. Even after considering common risk factors like age, sex, mental health, smoking and weight, people who had nightmares every week were still found to be nearly three times more likely to die prematurely – about the same risk as heavy smoking. The team also examined 'epigenetic clocks' – chemical marks on DNA that act as biological mileage counters. People haunted by frequent nightmares were biologically older than their birth certificates suggested, across all three clocks used (DunedinPACE, GrimAge and PhenoAge). ADVERTISEMENT The science behind the silent scream Faster ageing accounted for about 39% of the link between nightmares and early death, implying that whatever is driving the bad dreams is simultaneously driving the body's cells towards the finish line. How might a scream you never utter leave a mark on your genome? Nightmares happen during so-called rapid-eye-movement sleep when the brain is highly active but muscles are paralysed. The sudden surge of adrenaline, cortisol and other fight-or-flight chemicals can be as strong as anything experienced while awake. If that alarm bell rings night after night, the stress response may stay partially switched on throughout the day. Continuous stress takes its toll on the body. It triggers inflammation, raises blood pressure and speeds up the ageing process by wearing down the protective tips of our chromosomes. On top of that, being jolted awake by nightmares disrupts deep sleep, the crucial time when the body repairs itself and clears out waste at the cellular level. Together, these two effects – constant stress and poor sleep – may be the main reasons the body seems to age faster. Close-up of CT scan of brain. (Source: The idea that disturbing dreams foreshadow poor health is not entirely new. Earlier studies have shown that adults tormented by weekly nightmares are more likely to develop dementia and Parkinson's disease, years before any daytime symptoms appear. ADVERTISEMENT Growing evidence suggests that the brain areas involved in dreaming are also those affected by brain diseases, so frequent nightmares might be an early warning sign of neurological problems. Nightmares are also surprisingly common. Roughly 5% of adults report at least one each week and another 12.5% experience them monthly. Because they are both frequent and treatable, the new findings elevate bad dreams from a spooky nuisance to a potential public health target. Cognitive behavioural therapy for insomnia, imagery-rehearsal therapy – where sufferers rewrite the ending of a recurrent nightmare while awake – and simple steps such as keeping bedrooms cool, dark and screen free have all been shown to curb nightmare frequency. Before jumping to conclusions, there are a few important things to keep in mind. The study used people's own reports of their dreams, which can make it hard to tell the difference between a typical bad dream and a true nightmare. Also, most of the people in the study were white Americans, so the findings might not apply to everyone. And biological age was measured only once, so we cannot yet say whether treating nightmares slows the clock. Crucially, the work was presented as a conference abstract and has not yet navigated the gauntlet of peer review. Despite these limitations, the study has important strengths that make it worth taking seriously. The researchers used multiple groups of participants, followed them for many years and relied on official death records rather than self-reported data. This means we can't simply dismiss the findings as a statistical fluke. If other research teams can replicate these results, doctors might start asking patients about their nightmares during routine check-ups – alongside taking blood pressure and checking cholesterol levels. ADVERTISEMENT Therapies that tame frightening dreams are inexpensive, non-invasive and already available. Scaling them could offer a rare chance to add years to life while improving the quality of the hours we spend asleep. Author: Timothy Hearn, Senior Lecturer in Bioinformatics, Anglia Ruskin University This article is republished from The Conversation under a Creative Commons licence.
RTÉ News
25-06-2025
- Health
- RTÉ News
Why it can be harder to sleep during the summer
Analysis: Seasonal insomnia means summer sleeping for many of us is a time of tossing, turning and early waking By Timothy Hearn, Anglia Ruskin University As the days stretch long and the sun lingers late into the evening, most of us welcome summer with open arms. Yet for a surprising number of people, this season brings an unwelcome guest: insomnia. For these people, summer is a time of tossing and turning, early waking – or simply not feeling sleepy when they should. Far from just being a nuisance, this seasonal insomnia may chip away at mood, concentration and metabolic health. From RTÉ 2FM Morning with Laura Fox, sleep expert Síne Dunne on getting off to sleep But why does insomnia spike in summer — and more importantly, what can be done about it? The answer lies in the light. Every tissue in the body owns a molecular "clock". However, these clocks take their cue from a central timekeeper – the brain's suprachiasmatic nucleus. This cluster of about 20,000 neurons synchronises the myriad cellular clocks to a near 24-hour cycle. It uses the external light detected by the eyes as a cue, driving the release of two different hormones: melatonin, which makes us sleepy and a pre-dawn surge cortisol to help us wake. In winter, this light cue is short and sharp. But in June and July, daylight can stretch on for 16 or 17 hours in the mid‑latitudes. That extra dose matters because evening light is the most potent signal for pushing the central timekeeper later. In summer melatonin shifts by roughly 30 minutes to an hour later, while dawn light floods bedrooms early and kills the hormone off sooner. From RTÉ Brainstorm, the A to Zzzzz of sleep This can have a big effect on the amount of sleep we get. One study monitored the sleep of 188 participants in the lab on three nights at different times of the year. The researchers found that total sleep was about an hour shorter in summer than winter. Rapid eye movement (REM) sleep — the sleep stage most strongly linked to emotional regulation and the consolidation of emotionally charged memories — accounted for roughly half the sleep loss in summer. The same team later tracked 377 patients over two consecutive years and showed that sleep length and REM sleep began a five‑month decline soon after the last freezing night of spring. Sleep length shrank by an average of 62 minutes, while REM decreased by about 24 minutes. Slow-wave sleep – the phase most critical for tissue repair, immune regulation and the consolidation of factual memories – reached its annual low around the autumn equinox. Both studies took place in a city bathed in artificial light – suggesting that even in modern environments our sleep remains seasonally affected. From RTÉ Radio 1's Drivetime, you may be sleeping well, but are you actually getting rest? Big population surveys echo these findings. Among more than 30,000 middle‑aged Canadians, volunteers interviewed in midsummer said they slept eight minutes less than those interviewed in midwinter. The summer interviewees also reported greater insomnia symptoms in the fortnight after the autumn clock change – suggesting the abrupt time shift exacerbates underlying seasonal misalignment. One study also compared the effect of summer sleep in people living at very different latitudes – such as near the equator, where there's little change in day length in the summer, and near the Arctic circle, where the differences are extreme. The study found that for people living in Tromsø, Norway, their self-reported insomnia and daytime fatigue rose markedly in summer. But for people living in Accra, Ghana (near the equator), these measures barely budged. This show just how strongly daylight – and the amount of daylight hours we experience – can affect our sleep quality. But it isn't the only culprit of poor summertime sleep. Temperature is another factor that can spoil sleep during the summer months. Just before we fall asleep, our core body temperature begins a steep descent of roughly 1°C to help us fall asleep. It reaches its lowest point during the first half of the night. On muggy summer nights this can make falling asleep difficult. Laboratory experiments show that even a rise from 26°C to about 32°C increases wakefulness and reduces both slow-wave and REM sleep. Different people are also more vulnerable to summer insomnia than others. This has to do with your unique "chronotype" – your natural preference to rise early or sleep late. Evening chronotypes – "night owls" – already lean towards later bedtimes. They may stay up even later when it stays bright past ten o'clock. Morning chronotypes, on the other hand, may find themselves waking up even earlier than they normally do because of when the sun rises in the summer. From RTE Radio 1's Drivetime, sleep physiologist Motty Varghese on sleeping 14 hours a day Mood can amplify the effect. Research found people who suffered with mental health issues were more likely to experience difficulty sleeping in summer. Chronic anxiety, alcohol use and certain prescription drugs — notably beta blockers, which suppress melatonin — can all make sleep more elusive in summer. 4 ways to reclaim your summer sleep Happily, there are many ways of fixing the issue. Get some morning sunshine. Try to step outside within an hour of waking up – even if it's just for 15 minutes. This tells the clock that the day has begun and nudges it to finish earlier that evening. Create an artificial dusk. Around two hours before bed, close the curtains, turn off the lights and reduce the intensity of your phone screen's blue light to help your melatonin rise on time. Don't let the dawn light in. Being exposed to the dawn light too early will wake you up. Blackout curtains or a contoured eye-mask can ensure you don't wake before you're rested. Keep things cool. Fans, breathable cotton or linen sheets or a lukewarm shower before bed all help the body to achieve that crucial one-degree drop in core temperature needed to get a good night's sleep. The deeper lesson here from chronobiology is that humans remain, biologically speaking, seasonal animals. While our industrialised lives flatten the calendar, our cells still measure day length and temperature just as plants and migratory birds do. By adapting and aligning our habits with those light signals, we might just be able to recapture some sleep – even during the warmer months.
