About 700m years ago, the Earth froze over entirely – now we may know why
The Franklin eruptions – about 720m years ago – spewed out vast amounts of fresh rock, stretching from what is now Alaska, through northern Canada to Greenland. Similarly large eruptions have happened at other times, but this one happened to coincide with an already cold climate. And combined with a lack of plants (they hadn't evolved yet) these eruptions exposed a huge carpet of fresh rock to intense weathering.
Chemical reactions associated with weathering remove carbon dioxide from the air. By modelling the climate impact, researchers have shown that rapid erosion over such a large area could have pulled down enough carbon dioxide to tip Earth into a snowball state. The findings, which are published in the Journal of Geophysical Research: Planets, also show that similar-sized volcanic eruptions at other times in Earth's history failed to generate snowball conditions because they occurred when the background climate was hotter, or at times when vegetation cover slowed the rate of erosion.
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The Guardian
an hour ago
- The Guardian
7,000 steps a day could be enough to improve health, say researchers
Walking more could reduce your risk of dementia, depression and dying from cancer, as well as being good for your heart, according to research. And you may not need to walk as far as previously thought to reap those benefits. The NHS recommends a brisk 10-minute walk every day. Many people aim to walk 10,000 steps, but struggle to achieve it. Now researchers have calculated that even 7,000 steps could be enough to protect health. Scientists examined data from more than 160,000 adults and found that walking 7,000 steps a day was associated with a reduced risk of a number of serious health conditions and death. Whereas previous studies have mainly examined the links between step count and heart health or overall death rates, this systematic review and meta analysis, published in the Lancet Public Health, sought to comprehensively examine how taking more steps per day could reduce the risk of a range of other health conditions as well. Compared with those who walked 2,000 steps a day, the researchers found that achieving the 7,000 daily step target was linked to a 37% reduction in risk of dying from cancer, while the risk was 14% lower for type 2 diabetes, 38% for dementia, 22% depression and 28% for falls respectively. It was also associated with a 25% lower risk of cardiovascular disease and a 47% reduction in overall risk of dying. Although step count does not measure the quality or intensity of exercise, the findings underscore the importance of being active. There is a 'return on investment' with every additional 1,000 steps taken and even 4,000 steps per day reduced the risk of disease, compared with very low activity levels, the researchers observed. Although the risk continues to decrease above 7,000 steps, the rate at which it reduces that risk starts to slow. Melody Ding, professor of public health at the University of Sydney and lead author of the research, said that those who already walked 10,000 steps should not go back to 7,000, but that 7,000 was a more practical target for those who were currently inactive. 'Those who are currently active and achieving the 10,000 steps a day, keep up the good work – there is no need to modify your step counts. However, for those of us who are far from achieving the 10,000 targets, getting to 7,000 steps/day offers almost comparable health benefits for the outcomes we examined.' Responding to the findings, Dr Daniel Bailey, reader in sedentary behaviour and health at Brunel University of London, said the research helped 'debunk the myth that 10,000 steps per day should be the target for optimal health. 'The real-world implications are that people can get health benefits just from small increases in physical activity, such as doing an extra 1,000 steps per day. To achieve the best reductions in risk, aiming for 5,000-7,000 per day can be recommended, which will be more achievable for many people than the unofficial target of 10,000 steps that has been around for many years.' Dr Andrew Scott, senior lecturer in clinical exercise physiology at the University of Portsmouth, pointed out that not all activity was captured by step counts. 'The steps per day is useful when people's exercise is weight-bearing, however cycling, swimming and rowing are not well-represented by the steps-per-day model.' June Davison, senior cardiac nurse at the British Heart Foundation, said: 'We know that regular walking is one of the easiest ways to help maintain a healthy lifestyle and reduce your risk of heart disease. 'Adults should aim to build up to a total of 150 minutes of moderate-intensity activity every week, but getting active isn't always easy. Incorporating activity snacks, such as walking while taking phone calls, or taking a brisk 10-minute walk during your lunch break, can all count to reduce your chances of developing heart disease.'
The Independent
2 hours ago
- The Independent
Scientists say you don't need 10,000 steps a day. Here's how many to do instead
A new study suggests that hitting 7,000 steps a day could be sufficient to ward off a range of serious illnesses, offering a more attainable target than the widely publicised 10,000-step goal. While many find the latter difficult to achieve, new research indicates "sizeable" health benefits are still possible with fewer daily steps. Academics from the University of Sydney in Australia led the study, examining data from dozens of global studies, including those in the UK, involving tens of thousands of adults. Their findings revealed that individuals consistently walking 7,000 steps daily appeared to gain significant protection against various diseases. This included a 25 per cent lower risk of heart disease, a 14 per cent reduced risk of type 2 diabetes, a 38 per cent decrease in dementia, and a 22 per cent reduction in depression. Experts noted that even modest step counts of 4,000 steps a day could yield benefits over very low activity levels. However, they also clarified that "10,000 steps per day will still be better than 7,000 steps," with the higher count leading to even more comprehensive health advantages. The researchers also found that when people walked 7,000 daily steps, compared to walking 2,000 steps, they were 47 per cent less likely to die during the follow-up periods of the studies analysed. And while the number of steps walked did not sway whether or not a person got cancer, people who walked more steps were significantly less likely to die from cancer – with 37 per cent lower odds of cancer death compared to people who walked fewer steps. 'Although 10,000 steps per day can still be a viable target for those who are more active, 7,000 steps per day is associated with clinically meaningful improvements in health outcomes and might be a more realistic and achievable target for some,' the authors wrote in the journal Lancet Public Health. They added: 'Even modest daily step counts were associated with health benefits. '7,000 steps per day was associated with sizeable risk reductions across most outcomes, compared with the reference of 2,000 steps per day.' Commenting on the study, Dr Daniel Bailey, Reader – Sedentary Behaviour and Health, Brunel University of London, said: 'The finding that doing 5000-7000 steps per day is an important addition to the literature which helps to debunk the myth that 10,000 steps per day should be the target for optimal health. 'This study suggested that 5000-7000 steps per day can significantly reduce the risk of many health outcomes, but that does not mean you cannot get benefits if you don't meet this target. 'The study also found that health risks were reduced with each 1000 extra steps per day, up to a maximum of 12,000 steps per day. So just adding more steps from your starting point can have important benefits for health.' Dr Andrew Scott, senior Lecturer in clinical exercise physiology at the University of Portsmouth, added: 'In most cases, the 10,000 steps per day will still be better than 7,000 steps, just by decreasing margins of health benefit return. 'More important than the exact number of steps, it demonstrates that overall, more is always better and people should not focus too much on the numbers, particularly on days where activity is limited. 'The steps per day is useful when people's exercise is weight-bearing, however cycling, swimming and rowing are not well-represented by the steps per day model.'
The Guardian
2 hours ago
- The Guardian
7,000 steps a day could be enough to improve health, say researchers
Walking more could reduce your risk of dementia, depression and dying from cancer, as well as being good for your heart, according to research. And you may not need to walk as far as previously thought to reap those benefits. The NHS recommends a brisk 10-minute walk every day. Many people aim to walk 10,000 steps, but struggle to achieve it. Now researchers have calculated that even 7,000 steps could be enough to protect health. Scientists examined data from more than 160,000 adults and found that walking 7,000 steps a day was associated with a reduced risk of a number of serious health conditions and death. Whereas previous studies have mainly examined the links between step count and heart health or overall death rates, this systematic review and meta analysis, published in the Lancet Public Health, sought to comprehensively examine how taking more steps per day could reduce the risk of a range of other health conditions as well. Compared with those who walked 2,000 steps a day, the researchers found that achieving the 7,000 daily step target was linked to a 37% reduction in risk of dying from cancer, while the risk was 14% lower for type 2 diabetes, 38% for dementia, 22% depression and 28% for falls respectively. It was also associated with a 25% lower risk of cardiovascular disease and a 47% reduction in overall risk of dying. Although step count does not measure the quality or intensity of exercise, the findings underscore the importance of being active. There is a 'return on investment' with every additional 1,000 steps taken and even 4,000 steps per day reduced the risk of disease, compared with very low activity levels, the researchers observed. Although the risk continues to decrease above 7,000 steps, the rate at which it reduces that risk starts to slow. Melody Ding, professor of public health at the University of Sydney and lead author of the research, said that those who already walked 10,000 steps should not go back to 7,000, but that 7,000 was a more practical target for those who were currently inactive. 'Those who are currently active and achieving the 10,000 steps a day, keep up the good work – there is no need to modify your step counts. However, for those of us who are far from achieving the 10,000 targets, getting to 7,000 steps/day offers almost comparable health benefits for the outcomes we examined.' Responding to the findings, Dr Daniel Bailey, reader in sedentary behaviour and health at Brunel University of London, said the research helped 'debunk the myth that 10,000 steps per day should be the target for optimal health. 'The real-world implications are that people can get health benefits just from small increases in physical activity, such as doing an extra 1,000 steps per day. To achieve the best reductions in risk, aiming for 5,000-7,000 per day can be recommended, which will be more achievable for many people than the unofficial target of 10,000 steps that has been around for many years.' Dr Andrew Scott, senior lecturer in clinical exercise physiology at the University of Portsmouth, pointed out that not all activity was captured by step counts. 'The steps per day is useful when people's exercise is weight-bearing, however cycling, swimming and rowing are not well-represented by the steps-per-day model.' June Davison, senior cardiac nurse at the British Heart Foundation, said: 'We know that regular walking is one of the easiest ways to help maintain a healthy lifestyle and reduce your risk of heart disease. 'Adults should aim to build up to a total of 150 minutes of moderate-intensity activity every week, but getting active isn't always easy. Incorporating activity snacks, such as walking while taking phone calls, or taking a brisk 10-minute walk during your lunch break, can all count to reduce your chances of developing heart disease.'
