New York: An increase in physical activity can prevent new cases of dementia globally each year, a new study has revealed. According to the study, physical inactivity contributes to an estimated 5.3 million deaths each year, similar to the number of deaths attributed to tobacco use and obesity. The study, published in the journal The Lancet, suggested that despite evidence physical activity reduces disease risk and improves cognition, approximately 80 per cent of adolescents worldwide are not meeting guidelines calling for 60 minutes of moderate to rigorous daily physical activity. "Among adults, 23 per cent of the population worldwide fail to meet activity guidelines. Around 292,600 cases of dementia are reported every year globally. The World Health Organisation estimates 47.5 million people are living with dementia, but with an aging population that number will continue to increase," said James F. Sallis, researcher at the University of California. According to the study, since the 2012 Olympics more countries have been monitoring activity levels and have drafted national policies to combat the problem of physical inactivity, but the plans are operational in only 56 per cent of countries. Ahead of the Summer Olympic Games in London four years ago, the researchers reported that physical inactivity was a global pandemic that required urgent action. However, with the 2016 Olympic Games looming, they reported little change in activity levels worldwide. "We've wasted four years. There is great evidence that this is one of the big challenges in public health, but the actionable response has not been impressive or systematic," added Sallis. In the study, the researchers also described several barriers to implementing physical activity policies, such as an untrained workforce and the lack of multisector partnerships with transportation, education, sport and urban planning that are necessary to make substantial changes. In addition, each country has a unique set of challenges that make a uniform solution improbable. Technology is making work and leisure time more sedentary and there is a need to work with other sectors to de-emphasise cars and re-emphasise walking and biking, suggested the study.