Latest news with #circadianrhythms
The Sun
27-05-2025
- Health
- The Sun
The 2 key eating habits to trigger weight loss revealed – and you don't even need to change what you eat
Katrina Turrill Published: Invalid Date, THE key to weight loss might not be what you eat, but in fact WHEN you eat. When you eat breakfast and dinner could lead to a healthier body weight over time, say scientists. Researchers from the Barcelona Institute for Global Health (ISGlobal) found eating breakfast early and extending your overnight fast by also eating dinner early can help you keep your weight in check. The study tracked more than 7,000 adults between the ages of 40 and 65. Back in 2018, they answered detailed questions about their diet, lifestyle, meal times, and body measurements. Five years later, more than 3,000 of them returned for a follow-up to provide updated health information. 'Our results, in line with other recent studies, suggest that extending the overnight fast could help maintain a healthy weight if accompanied by an early dinner and an early breakfast, explained Luciana Pons-Muzzo, researcher at ISGlobal at the time of the study. "We think this may be because eating earlier in the day is more in line with circadian rhythms and allows for better calorie burning and appetite regulation, which can help maintain a healthy weight. "However, it is too soon to draw definitive conclusions, so recommendations will have to wait for more robust evidence." The researchers found notable differences when looking at the data by gender. On average, women had lower BMIs than men and were more likely to follow the Mediterranean diet - a way of eating based on the traditional cuisine of countries bordering the Mediterranean Sea, emphasising plant-based foods and healthy fats, and recommended for its health benefits. They also tended to drink less alcohol and take on more household or care giving responsibilities. I lost almost a stone in just six days and here's the exact list of delicious meals I ate which never left me hungry Restricting your eating window to a specific time each day or week and abstaining from food for the rest of the time is known as intermittent fasting. Emerging evidence suggests it goes beyond weight loss, offering potential benefits for metabolic health, athletic performance, and even slowing the progression of certain diseases. But fasting and skipping breakfast could have a detrimental impact on health. Looking at the results of their analysis, the researchers were struck by a small group of men whose first meal of the day was after 2pm and who, on average, fasted for 17 hours. Compared to other participants, this group of men tended to have less healthy lifestyles (were more likely to smoke, drink alcohol, do less physical activity, and had less adherence to the Mediterranean diet). 'There are different ways of practising what is known as 'intermittent fasting' and our study relates to one of them, which is overnight fasting, says Camille Lassale, ISGlobal researcher and senior co-author of the study. "What we observed in a subgroup of men who do intermittent fasting by skipping breakfast is that this practice has no effect on body weight. "Other intervention studies in participants with obesity have shown that this tactic is no more effective than reducing calorie intake in reducing body weight in the long term." When practising intermittent fasting, remember to prioritise staying hydrated, choose a suitable approach for your lifestyle, and focus on healthy eating during your eating window. Consider starting with a 12-hour fast and gradually increasing the duration as needed. It's also important to be mindful of potential side effects like fatigue and dizziness, and to consult with a doctor, especially if you have any underlying health conditions. What are the health benefits of fasting? Weight loss Fasting can promote weight loss by reducing calorie intake and potentially increasing fat burning. Improved blood sugar control Fasting can help regulate blood sugar levels and improve insulin sensitivity, potentially reducing the risk of type 2 diabetes. Metabolic changes Fasting can alter metabolic processes, making the body more efficient at utilising fuel and potentially improving lipid profiles (cholesterol). Improved cognitive function Some studies suggest that fasting may enhance cognitive function, learning, memory, and alertness. Neuroprotective effects Fasting has been linked to neuroprotective properties, potentially reducing the risk of neurodegenerative diseases. Potential for increased longevity Research suggests that fasting may be associated with increased lifespan and a delay in age-related diseases. Heart health Fasting may positively impact heart health by reducing blood pressure and improving cardiovascular function. Improved gut health Fasting can influence gut microbiota, potentially improving gut health and immunity.
CNA
17-05-2025
- Health
- CNA
What's the best way to wake up? Snooze less and embrace the morning sunlight
You've heard plenty of advice about how to prepare for a good night's sleep, but what about waking up? Is there really an ideal way to start your day? Your schedule often determines exactly when you get out of bed. But to the extent you can shape your routine, experts have some thoughts on the healthiest morning habits. 'I always joke that the best thing to do is to get a puppy,' said Mariana Figueiro, who studies light and health at the Ichan School of Medicine at Mount Sinai. She's only half kidding. The two keys to a healthy wake-up routine, she said, are getting up at a consistent time each day and viewing morning sunlight – both tend to come with a regular morning dog walk. We spoke with four other sleep and circadian rhythm experts who all agreed with Dr Figueiro about the importance of these two morning habits. Here are their other recommendations – dog or no dog. STAY CONSISTENT Assuming you had the flexibility to choose, is there an ideal time to wake up? Not exactly. As long as you sleep for seven to nine hours each night, there's no 'best' time to wake up, said Dr Daniel Barone, the associate medical director of the Weill Cornell Center for Sleep Medicine. More important is that you stick to the same time, said Dr Katherine Sharkey, an associate professor who studies sleep at the Warren Alpert Medical School of Brown University. Your body runs on circadian rhythms that regulate not only your sleep-wake cycle but also your metabolism, appetite, hormones, mood, body temperature and cognitive function. Waking up at a consistent time can help keep these body functions running smoothly, said Helen Burgess, the co-director of the Sleep and Circadian Research Laboratory at the University of Michigan. Waking up much later or earlier than you're used to can make you feel drowsy or uncoordinated. Longer term, researchers have found links between irregular sleep patterns and increased risks of obesity, diabetes, mood disorders, heart disease and cancer. DON'T LET WEEKENDS THROW YOU OFF If you feel tired enough to sleep in on weekends, Dr Figueiro said, you're probably not getting enough rest during the week. In these cases, Dr Sharkey suggested sticking to your typical wake-up time and taking a nap later that day. This can help keep your circadian rhythms in sync. If you feel you absolutely must sleep in, Dr Barone said you can likely get away with an extra hour. Any longer and you might experience drowsiness, digestive issues and trouble focusing, similar to jet lag. (Sleep experts use the term ' social jet lag ' to refer to the effects of staying up late and sleeping in on weekends.) SEEK OUT SUNLIGHT As soon as you wake up, open the blinds and switch on the lights. Then, as soon as you can – ideally within an hour, Dr Figuiero said – try to get outside. Viewing any light in the morning, especially sunlight, helps signal to your body that it's daytime, Dr Sharkey said. When the light hits your eyes, it triggers a pathway between your brain and your adrenal glands that tells your body to release cortisol. This hormone makes you feel alert, which in turn could boost your mood, she added. S ome limited s tudies suggest that viewing morning sunlight can improve your sleep the following night, too. When the sun hits your eyes, Dr Sharkey said, it triggers a metaphorical stopwatch, which begins the countdown to bedtime, later telling your body when to release the sleep hormone melatonin. Even on overcast days, morning sunlight is strong enough to regulate your body clock, Dr Barone said. But if you wake up when it's still dark, he said it can be useful to turn on a powerful artificial light such as a light box. You might also try waking up to a sunrise alarm clock, he said, which gradually becomes brighter to mimic the rising sun. There's no specific amount of time you must spend in the morning sunlight, experts said, but, more exposure is better (as long as you protect your skin). Dr Burgess said an hour is best, but even 15 minutes is better than nothing. SKIP THE SNOOZE BUTTON Snoozing your alarm may feel like a gift to yourself, but it isn't the best way to start your day, said Ann E Rogers, a sleep researcher and professor of nursing at Emory University. The urge to snooze is your body's way of saying you need more sleep, Dr Sharkey said. And if you have the flexibility in your schedule to hit snooze, the experts agreed you're better off setting your alarm for the later end of your snooze window and getting up then. That way, your body can get the extra rest it craves – uninterrupted.
Medscape
09-05-2025
- Health
- Medscape
Keep Clocks on Permanent Standard Time, Says Canadian Group
The annual switch to daylight saving time (DST) in many parts of the world is detrimental to public health and should be abolished in favor of permanent standard time (ST), Canadian researchers wrote in a recent editorial. The policy of turning clocks forward by an hour in the spring causes 'discrepancies between the circadian biological clock and the environmental light-dark cycle,' leading to 'social jet lag,' noted lead author David Dongkyung Kim, MD, assistant professor of geriatric psychiatry at the University of Toronto, Toronto, and colleagues. The Viewpoint was published on April 29 in JAMA. Clear Evidence 'DST is a policy that affects the lives of millions of people, but the potential benefits do not seem to outweigh the potential harms to public health,' Kim told Medscape Medical News. 'Clear evidence in the medical literature as well as widespread expert consensus [shows] the acute transition of the clock time in the spring has been associated with increased myocardial infarction, ischemic stroke, and atrial fibrillation admissions,' he added. 'But it is not only the sudden change in the clock that is the issue. ST is more aligned with our natural circadian rhythms, and chronic misalignment has been associated with many negative health effects.' Canada first initiated DST during World War I. The rationale was to add more light to waking hours, thus saving energy. Today, only Saskatchewan and Yukon have abolished the time change, staying on permanent ST. Ontario passed legislation in 2020 to change to permanent DST, but it was contingent on Quebec and New York doing likewise, said Kim. 'Many studies seem to show an acute worsening of health with the spring transition, but not the fall transition, suggesting the health issues are due not only to acute changes in clock time but also to the discrepancy between clock time and circadian rhythm,' the authors noted. 'Although many studies suggest increased traffic crashes due to DST transition, others do not show this connection,' they added. And findings on DST transition and mental health risks such as unipolar depression, manic episodes, and suicide are also mixed. 'The main argument I hear for establishing permanent DST is that it is nicer to see the sun set later in the day,' said Kim. 'To that, I respond that you can use your own volition to wake up an hour earlier without forcing permanent DST on the entire population.' Late evening light, which DST makes possible, disrupts the natural seasonal adjustment of circadian rhythms. The misalignment between one's personal schedule and the circadian rhythm, which is called social jet lag, is well understood. It is associated with negative outcomes such as obesity, heart disease, metabolic syndrome, and depression. Global Consensus In a position statement, the Canadian Sleep Society called for abandoning DST, and there is 'global consensus from sleep and chronobiology experts on this matter,' said Rébecca Robillard, PhD, a clinical neuropsychologist and associate professor of psychology at the University of Ottawa, Ottawa. Robillard, who did not contribute to the editorial, also leads clinical sleep research at the University of Ottawa Institute of Mental Health Research at the Royal Ottawa Mental Health Centre and is co-chair of the Canadian Sleep Research Consortium. 'Considering the impacts that this practice has on a large range of health and safety issues, we should abolish DST and stick to ST all year around,' she told Medscape Medical News. 'Time change goes beyond gaining or losing an hour of sleep; it perturbs our biological clock, which results in population-wide increases in heart attacks, strokes, infections and immune diseases, digestive problems, pregnancy and childbirth complications, and a deterioration in mental health. It's not a question of opinion or personal preference, but of public health and scientific evidence.' Kim and Robillard reported having no relevant financial relationships.
