In the second study, Brazilian researchers showed that about one-third of adults throughout the world are at high risk of disease because of their lack of physical activity.
The researchers defined the recommended amounts of moderate activity as at least 30 minutes or more, five times per week, or vigorous activity for 20 minutes three times per week. They found that inactivity rises with age. It is more prevalent in high-income countries and is higher in women than men.
Of note, several low-income countries in Africa and the poorest regions of Latin America had inconclusive data to properly show inactivity rates for the study.
A third paper conducted by University of Tennessee researchers analyzed successful and promising interventions that can be used to work more physical activity into daily life.
"Because even moderate physical activity such as walking and cycling can have substantial health benefits, understanding strategies that can increase these behaviors in different regions and cultures has become a public health priority," Dr. Gregory Heath, lead author of the study, said in a statement.
After examining more 100 reviews of exercise interventions between 2001 and 2001, researchers found that the most successful ones included community exercise events and social support networks, such as buddy systems and walking clubs. Creating surrounding areas that are conducive to walking, biking and running encouraged people to get out and exercise more, and several studies showed that lighting and aesthetics of exercise areas can improve levels by up to 50 percent.
Whether technology or apps, running paths or lighted parks are available, Keith Ayoob, associate professor of pediatrics at Albert Einstein School of Medicine in New York said, it's important to "just move. Period."
"There's no substitute for low-tech moving, but there are apps and such that can motivate and help track," said Ayoob. "And we need to learn to decrease sedentary leisure activities. Sometimes you have to just power down to strengthen up."
With so many people throughout the world connected to mobile devices, there is indeed a place for apps. Researchers from the CDC found that text messages and other communications through mobile devices could successfully contribute to exercise interventions.
Finally, in a fifth paper, researchers said the prevalence of inactivity and its extreme effect on global health makes the problem a pandemic.
"The response to physical inactivity has been incomplete, unfocused, and most certainly understaffed and underfunded, particularly compared with other risk factors for non-communicable diseases," Dr. Harold W. Kohl, III of The University of Texas Health School of Public Health and lead author of the fifth paper, said in a statement.
Kohl and his colleagues noted in the study that exercise should be worked into a multifaceted system in society, through transportation, education, government, medical prevention and public health programs. Community-based efforts, rather than focusing on individual physicality, will be more beneficial in increasing exercise worldwide.
"The analysis here is convincing," said Katz of the Lancet series. "And common sense supports the conclusion reached by science: Failure to put our innate animal vitality through its native paces is taken life from our years, and years from our lives."