If you don't already lift weights, it may be time to start. According to researchers from Japan, just 30 to 60 minutes of muscle-strengthening exercise a week is enough to lower a person's risk of early death. Muscle-strengthening exercise can include activities like push-ups, yoga and walking up steps, among others. The research was based on 16 previously published studies that had between 4,000 and 480,000 adult participants. The studies were done in the US, England, Scotland, Australia and Japan. The participants had no serious health issues, and they were monitored for at least two years. The results, published in the British Journal of Sports Medicine, showed that those who did between 30 and 60 minutes of strength or weight training a week had a 10% to 20% lower risk of early death from all causes. This type of exercise was also found to lower the risks of heart disease and cancer by about the same amount. Participants who reported doing a combination of muscle training and aerobic activity were found to have a 40% lower risk of death from all causes, 46% lower risk of heart disease, and 28% lower risk of death from cancer. However, after 130 to 140 minutes of muscle training, the positive health effects decreased, and were only seen in issues related to diabetes. Speaking with CNN, University of Minnesota professor William Roberts, who was not part of the study, said the results are good for people who want to improve their health but don't have much time for exercise.