60 minutes of endurance training is enough to shift body clock in mice
June 15, 2020
Science Daily/The Physiological Society
New research published today in the Journal of Physiology shows that just one 60 minutes bout of exercise shifted the muscle clocks of mice by around an hour in either direction. If this research is replicated in humans, it makes a case for prescribing exercise for night-shift workers and for treating diseases like heart disease, both of which can result in disrupted clocks throughout the body.
Clocks exist in virtually all our cells to temporally coordinate cell specific functions. The setting of our clocks are sensitive to cues like changes in light throughout the day, or our time of eating. Researchers at the University of Florida found that the clocks in muscles of mice were "listening" to information from their muscle contractions during exercise.
This means that exercise is a cue for setting the clocks in muscles. The researchers determined this by studying mice that ran in different phases of the day: in the middle of their rest phase, an hour before starting their active phase, and in the middle of their active phase. Active and rest phases in mice are equivalent to day and night in humans. They then looked at how the amount of a primary clock protein changed over the course of multiple days following muscle contractions. Their results showed that depending on the timing of contractions the clocks shifted about an hour to either an earlier or later time and that this does not require circulating hormones or the central clock.
In other words, the timing of exercise during the day, can rewind or fast forward our muscle body clocks, so fine-tuning this could allow precise treatment of conditions where the body clocks either is running ahead or behind.
Researchers carried this research out in mice rather than humans as it would require multiple muscle biopsies, which are invasive procedures. Although this research has been done in mice thus far, it can be taken forward in patients without the need for clinical trials, as it calls for a prescription of exercise timing for certain conditions, such as heart disease.
Christopher Wolff, a co-first author on the study said:
"This research is really important because it highlights the effect exercise can have on our body clocks. If this is replicated in humans it means that night-shift workers can use exercise to help shift their body clocks. We may also be able to use exercise as a treatment for 'body clock disorders' that can occur in many chronic diseases such as heart disease."
https://www.sciencedaily.com/releases/2020/06/200615212715.htm
Night owls can 'retrain' their body clocks to improve mental well-being and performance
June 10, 2019
Science Daily/University of Birmingham
A simple tweak to the sleeping patterns of 'night owls' -- people with extreme late sleeping and waking habits -- could lead to significant improvements in sleep/wake timings, improved performance in the mornings, better eating habits and a decrease in depression and stress.
New international research by the Universities of Birmingham and Surrey in the UK, and Monash University in Australia, showed that, over a three-week period, it was possible to shift the circadian rhythm of 'night owls' using non-pharmacological and practical interventions.
The study, recently published in Sleep Medicine, showed participants were able to bring forward their sleep/wake timings by two hours, while having no negative effect on sleep duration. In addition, participants reported a decrease in feelings of depression and stress, as well as in daytime sleepiness.
"Our research findings highlight the ability of a simple non-pharmacological intervention to phase advance 'night owls', reduce negative elements of mental health and sleepiness, as well as manipulate peak performance times in the real world," lead researcher Dr Elise Facer-Childs from Monash University's Turner Institute for Brain and Mental Health said.
'Night owls' are individuals whose internal body clock dictates later-than-usual sleep and wake times -- in this study participants had an average bedtime of 2.30am and wake-up time of 10.15am.
Disturbances to the sleep/wake system have been linked to a variety of health issues, including mood swings, increased morbidity and mortality rates, and declines in cognitive and physical performance.
"Having a late sleep pattern puts you at odds with the standard societal days, which can lead to a range of adverse outcomes -- from daytime sleepiness to poorer mental wellbeing," study co-author Dr Andrew Bagshaw from the University of Birmingham said.
"We wanted to see if there were simple things people could do at home to solve this issue. This was successful, on average allowing people to get to sleep and wake up around two hours earlier than they were before. Most interestingly, this was also associated with improvements in mental wellbeing and perceived sleepiness, meaning that it was a very positive outcome for the participants. We now need to understand how habitual sleep patterns are related to the brain, how this links with mental wellbeing and whether the interventions lead to long-term changes."
Twenty-two healthy individuals participated in the study. For a period of three weeks participants in the experimental group were asked to:
· Wake up 2-3 hours before regular wake up time and maximise outdoor light during the mornings.
· Go to bed 2-3 hours before habitual bedtime and limit light exposure in the evening.
· Keep sleep/wake times fixed on both work days and free days.
· Have breakfast as soon as possible after waking up, eat lunch at the same time each day, and refrain from eating dinner after 7pm.
The results highlighted an increase in cognitive (reaction time) and physical (grip strength) performance during the morning when tiredness is often very high in 'night owls', as well as a shift in peak performance times from evening to afternoon. It also increased the number of days in which breakfast was consumed and led to better mental well-being, with participants reporting a decrease in feelings of stress and depression.
"Establishing simple routines could help 'night owls' adjust their body clocks and improve their overall physical and mental health. Insufficient levels of sleep and circadian misalignment can disrupt many bodily processes putting us at increased risk of cardiovascular disease, cancer and diabetes," Professor Debra Skene from the University of Surrey said.
Dr Facer-Childs said 'night owls', compared to 'morning larks', tended to be more compromised in our society due to having to fit to work/school schedules that are out of sync with their preferred patterns.
"By acknowledging these differences and providing tools to improve outcomes we can go a long way in a society that is under constant pressure to achieve optimal productivity and performance," she said.
This intervention could also be applied within more niche settings, such as industry or within sporting sectors, which have a key focus on developing strategies to maximise productivity and optimise performance at certain times and in different conditions.
https://www.sciencedaily.com/releases/2019/06/190610100622.htm
How eating feeds into the body clock
April 25, 2019
Science Daily/Medical Research Council
New research has found it is not just what you eat, but when you eat that is important -- knowledge which could improve the health of shift workers and people suffering from jet lag.
The Medical Research Council (MRC)-funded study, published today in the journal Cell, is the first to identify insulin as a primary signal that helps communicate the timing of meals to the cellular clocks located across our body, commonly known as the body clock.
The team behind the research believe this improved understanding may lead to new ways to alleviate the ill-health associated with disruption to the body clock. These could include eating at specific times or taking drugs that target insulin signalling.
The body clock -- also known as the circadian rhythm -- is a 24-hour biological cycle that occurs individually in every cell of the body, driving daily rhythms in our physiology, from when we sleep, to hormone levels, to how we respond to medication. Our body clock is synchronised with the surrounding environment by exposure to daylight and the timing of meals. This synchrony is important for long-term health, and it is well known that disrupting your circadian rhythm by shift work or travel across time zones can be detrimental for health. Importantly, it is thought that eating at unusual times, as often occurrs during shift work and jet lag, is a major cause of body clock disruption. However, it has not previously been known exactly how the body clock senses and responds to meal timing, making it difficult to provide medical advice or interventions that might alleviate the problem.
Researchers at the MRC Laboratory of Molecular Biology (LMB) in Cambridge and the University of Manchester have now identified insulin as a primary signal that helps communicate the timing of meals to the cellular clocks across our body, and in doing so strengthen the circadian rhythm. The team's experiments in cultured cells, and replicated in mice, show that insulin, a hormone released when we eat, adjusts circadian rhythms in many different cells and tissues individually, by stimulating production of a protein called PERIOD, an essential cog within every cell's circadian clock.
Dr John O'Neill, a research leader at the MRC LMB who led the Cambridge research team, said: "At the heart of these cellular clocks is a complex set of molecules whose interaction provides precise 24-hour timing. What we have shown here is that the insulin, released when we eat, can act as a timing signal to cells throughout our body."
Working with Dr David Bechtold, a senior lecturer at the University of Manchester, the researchers found that when insulin was provided to mice at the 'wrong' biological time -- when the animals would normally be resting -- it disrupted normal circadian rhythms, causing less distinction between day and night.
Dr Bechtold said: "We already know that modern society poses many challenges to our health and wellbeing -- things that are viewed as commonplace, such as shift-work, sleep deprivation, and jet lag, disrupt our body clock. It is now becoming clear that circadian disruption is increasing the incidence and severity of many diseases, including cardiovascular disease and type 2 diabetes."
Dr Priya Crosby, a researcher at the MRC LMB and lead author on the study, highlighted: "Our data suggests that eating at the wrong times could have a major impact on our circadian rhythms. There is still work to do here, but paying particular attention to meal timing and light exposure is likely the best way to mitigate the adverse effects of shift-work. Even for those who work more traditional hours, being careful about when we eat is an important way to help maintain healthy body clocks, especially as we age."
https://www.sciencedaily.com/releases/2019/04/190425143607.htm