The Government recommends that adults undertake at least 150 minutes of moderately intense physical activity a week, such as cycling or fast walking, as well as exercises to strengthen the legs, torso and arms on at least two days a week.But the BHF’s Physical Inactivity and Sedentary Behavior Report 2017 finds that in some parts of the country nearly half of adults are not meeting the official guidelines.Levels were worst in the North West of England, where 47 per cent of adults, around 2,640,000 people, were failing to do the bare minimum, while in Northern Ireland the proportion was 46, Wales and the North East 42, and London 40 per cent.Physical inactivity in Scotland was found to be relatively good at 37 per cent, just ahead of South West England and South East England at 35 and 34 per cent respectively.Dr Mike Knapton, Associate Medical Director at the BHF, described reluctance to exercise as “one of the most significant global health crises of the moment”.“Levels of physical inactivity and sedentary behaviour in the UK remain stubbornly high, and combined these two risk factors present a substantial threat to our cardiovascular health and risk of early death,” he said. The new report also sets out evidence showing that, regardless of how much exercise they take, people who spend a large amount of their time sitting down put themselves at greater risk of cardiovascular disease.The BHF estimates that the average man in the UK spends a fifth of their lifetimes sitting, the equivalent of 78 days each year, while women were found to be sedentary for the equivalent of 74 days a year.As well as increasing numbers of people working in sedentary office-based jobs, the average UK adult spends almost 30 hours television, equivalent to 64 days a year, according to Ofcom. Levels of physical inactivity and sedentary behaviour in the UK remain stubbornly highDr Mike Knapton, BHF Associate Medical Director The Government recommends 150 minutes of moderately intense exercise a weekCredit:Alamy A third of Britons are putting themselves at risk of an early grave because they do hardly any exercise, a new report reveals.The British Heart Foundation (BHF) today warns that swathes of the population are needlessly heightening their chances of developing potentially fatal cardiovascular diseases by as much as 35 per cent.The research also finds that there is a significant risk of illness even among those who do exercise sufficiently, due to the length of time many of them spend sitting down at work. However, the charity’s warning contradicts other recent research which suggests that people who exercise only at the weekend can lower their risk of early death from heart disease, as well as cancer.The new report also found that women are 36 per cent more likely to be classed as physically inactive compared to men, and that in some parts of the country 97 per cent of patients referred for cardiac rehabilitation after suffering a heart attack or undergoing heart surgery took barely any exercise.“Making physical activity easier and more accessible for all is of paramount importance if we are to reduce the burden of inactivity-related ill health,” said Dr Knapton.”As part of an effort to prompt better exercise levels, the BHF is today launching its MyMarathon challenge, whereby people of all fitness levels are encouraged to run 26.2 miles in whatever chunks they choose.” Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.