Even Lower Levels of Activity are Associated with Improved Health
With the advent of low-cost accelerometers, epidemiological studies are beginning to show that even lower levels of sustained activity correlate with reduced mortality and improved health: walking, gardening, cleaning, and similar tasks that don't rise to the level of vigorous exercise. Animal studies of vigorous exercise show that this exercise causes gains in long-term health, and the consensus is that this is the direction of causation for correlations observed in human data. Should we expect the same to hold for lower levels of activity in humans, where there is no comparable animal data to support causation? This study does not make use of accelerometers, but does include populations that are not frequently assessed, and finds the same association between health and low levels of activity.
Physical activity of any kind can prevent heart disease and death, says a large international study involving more than 130,000 people from 17 countries. The Prospective Urban Rural Epidemiology (PURE) study shows any activity is good for people to meet the current guideline of 30 minutes of activity a day, or 150 minutes a week to raise the heart rate. Although previous research, from high income countries, shows leisure time activity helps prevent heart disease and death, the PURE study also includes people from low and middle-income countries where people don't generally don't participant in leisure-time physical activity. "By including low and middle-income countries in this study, we were able to determine the benefit of activities such as active commuting, having an active job or even doing housework." One in four people worldwide do not meet the current activity guideline and that number is nearly three of four in Canada.
The PURE study showed that by meeting the activity guidelines, the risk for death from any cause was reduced by 28%, while heart disease was reduced by 20%, and it didn't matter what type of physical activity the person did. The benefits also continued at very high levels with no indication of a ceiling effect; people getting more than 750 minutes of brisk walking per week had a 36% reduction in risk of death. However, less than 3% of participants achieved this level from leisure time activity while 38% of participants achieved this level from activities such as commuting, being active at work or doing household chores.
"Going to the gym is great, but we only have so much time we can spend there. If we can walk to work, or at lunch time, that will help too. For low and middle income countries where having heart disease can cause a severe financial burden, physical activity represents a low-cost approach that can be done throughout the world with potential large impact. If everyone was active for at least 150 minutes per week, over seven years a total of 8% of deaths could be prevented,"