What Exercise Authorities Aren’t Telling You About Optimal Duration
Physical fitness authorities often recommend achievable goals rather than providing guidance based solely on scientific findings, much like what is seen in nutrition recommendations.
Some researchers, funded by organizations like the Coca-Cola Company, have called physical inactivity “the biggest public health problem of the 21st century.” However, physical inactivity ranks lower in terms of risk factors for death in the U.S., coming in at number five, and is even lower globally. The greatest risk factor for death is diet, followed by smoking.
That said, exercise still plays a significant role in health. It helps with mental health, cognitive function, sleep quality, cancer prevention, immune function, high blood pressure, and longevity. For instance, if the U.S. population collectively reduced its body mass index by just 1%, it could prevent 2 million cases of heart disease and stroke, and 100,000 cancer cases.
How Much Should We Exercise?
The latest Physical Activity Guidelines for Americans recommend adults get at least 150 minutes per week of moderate aerobic exercise, which translates to about 20 minutes daily. This is a reduction from the previous guidelines from the Surgeon General, CDC, and American College of Sports Medicine, which recommended 30 minutes daily. The updated guidelines seem more focused on what is achievable, rather than strictly following the science.
Authorities acknowledge that “some physical activity is better than none.” However, it would be more helpful if they simply communicated the truth, based on scientific evidence.
Benefits of Walking
Walking 150 minutes per week is better than walking 60 minutes per week. Following the current recommendation of 150 minutes a week can reduce overall mortality by 7% compared to being sedentary. Walking for just 60 minutes a week reduces mortality by about 3%, while walking 300 minutes per week lowers mortality by 14%. A full hour of walking every day may reduce mortality by 24%.
Walking is a universally accessible form of exercise, but the same benefits apply to other moderate-intensity activities like gardening or cycling.
The Research on Exercise Duration
A meta-analysis of physical activity and longevity found that an hour of brisk walking (about 4 miles per hour) daily is beneficial. Interestingly, 90 minutes of exercise per day showed even more pronounced benefits. However, there weren’t enough studies to determine the benefits of exercising beyond 90 minutes daily.
If 90 minutes of exercise a day is better than 60 minutes, and 60 minutes is better than 30 minutes, why is the official recommendation still only 30 minutes? With only about half of Americans even achieving the recommended 20 minutes daily, authorities likely aim for goals that are more achievable. However, simply telling the public the truth about what science suggests might be more effective.
Resource: Nutritionfacts.org
