Women who are larks, otherwise known as “morning people”, have a lower risk of developing breast cancer, a study has revealed. While the exact reason why remains unknown, the team of researchers from the University of Bristol in the UK say their findings are important and add to the growing understanding of how sleep affects our health. A person’s body clock (also known as their circadian rhythm) regulates when a person feels sleepy or awake over a 24-hour period. So-called morning people wake up earlier, peak earlier in the day and feel sleepy earlier in the evening. In contrast, “evening people” (night owls) get up later, peak later in the day and go to sleep later in the evening. Using a data analysis technique called Mendelian randomisation, the researchers looked at DNA snippets of more than 400,000 women. They discovered that women who were larks were less likely to have breast cancer than their night owl peers. Speaking about the findings of the research, Dr Rebecca Richmond, a researcher from the University of Bristol, told the BBC: “The findings are potentially very important because sleep is ubiquitous and easily modified. “Previous research has looked at the impact of shift work, but this is showing there may be a risk factor for all women.” Nevertheless, many questions still remain. For example, more research now needs to be conducted to see whether the body clock itself is directly impacting a person’s risk of developing cancer, or if factors like night owls breaking their natural circadian rhythm to accommodate jobs is having an impact. [Related reading: Major study finds eating processed meat raises risk of breast cancer]
Wounds that occur during daylight hours heal faster than wounds that occur after dark, a new study has found. The research discovered that burns sustained at night took, on average, 28 days to heal, while burns that occurred during the day only took 17 days. In fact, the team from the UK's MRC Laboratory of Molecular Biology, which carried out the research, said the healing difference between daytime burns and night time burns was astounding. Publishing the findings of their research in Science Translational Medicine, the team of scientists said the difference in healing times was down to the way the human body clock ticks inside nearly every human cell over a 24-hour period. Specifically, fibroblasts, which are the body’s first responders that immediately head to a wound, are primed and ready to go during the daytime. However, at night, they lose this ability. It’s thought the research could lead to improvements in surgical procedures in the future. For example, drugs that reset a patient’s body clock could provide additional benefits during night-time procedures. Dr John O'Neill, one of the researchers, likened the way in which fibroblasts work to a running race: "It is like the 100m. The sprinter down on the blocks, poised and ready to go, is always going to beat the guy going from a standing start,” he said.
A new study by the University of Cambridge in the UK has found that viruses are more dangerous when they infect people in the mornings. In fact, the findings of the study, which were published in the medical journal PNAS, show that virus infections that occur in the morning can be up to 10 times more dangerous for the individual. For the study, the Cambridge researchers infected mice at different times of the day with either influenza or herpes. They then looked whether there was any correlation between the time of day when the infection occurred and the potency of the virus. Mice that were infected in the morning were found to have viral levels 10 times higher than those infected in the evening. Unlike bacteria or parasites, viruses rely on the cells of their host to replicate and grow. However, those cells change dramatically throughout the day as part of our 24-hour body clocks. The researchers say their findings could pave the way for stopping pandemics. For example, when faced with a pandemic, it could be life-saving for people to stay inside during the daytime. A virus infection in the evening is like someone trying to hijack a factory once all the workers have gone home. In other words, it's likely to be unsuccessful.