During the COVID-19 pandemic, many of us have seen a resurgence of walkers in our neighborhoods. This has been a wonderful way to step outside the confines of homes, enjoy some fresh air and get some exercise while still maintaining physical distancing.
Engaging in a brisk walk most days of the week is also a great way to meet physical activity recommendations for adults. Numerous expert panels recommend adults get at least a total of 150 minutes of moderate physical activity every week (such as brisk walking), and do muscle-strengthening activities two days per week. Of course, those 150 minutes per week can be divided in many different ways. Some people aim for 30 minutes of exercise five days a week. Others fit in 10 minutes of moderate intensity exercise several times a day.
Counting Steps versus Counting Minutes
Many of my patients have been walking for exercise long before the current pandemic; at our annual visits, we have discussed their weekly walking activity in terms of pace (for example, 15-minute miles, two miles per walk, five walks per week) so I can add up their weekly tally in minutes of brisk walking to see if they are meeting national guideline recommendations. With the advent of digital technology, many patients are now tracking (and reporting) their walking activities in terms of steps. Some may assume if they reach their goal of walking at least 10,000 steps per day, they have been meeting national physical activity goals and more importantly, garnering the many health benefits of meeting those goals.
There are mountains of data spanning more than 30 years, including landmark studies from The Cooper Institute, supporting the health benefits of engaging in 150 minutes per week of moderate physical activity (walking briskly at about 3.5 miles per hour, bicycling less than 10 miles per hour, raking the yard, dancing, doubles tennis) or 75 minutes per day of vigorous physical activity (running or jogging at five miles per hour, walking very fast at 4.5 miles per hour, bicycling faster than 10 miles per hour, chopping wood, swimming laps, competitive basketball, singles tennis).
The hallmark of engaging in moderate physical activity is that you are exerting yourself with enough intensity that your breathing rate and heart rate are increased.
What does the data tell us about the health benefits of accumulating 10,000 steps per day? You might be surprised to hear that when Fitbit launched its first device, which tracked steps, more than 10 years ago, the benchmark of achieving 10,000 steps per day dated back to a health marketing campaign from the 1960s.
At that time, Japan was preparing to host the 1964 Tokyo Olympics and identified a need for increased fitness in the general Japanese population. Walking was identified as a simple way to exercise that did not require special equipment and could be embraced by young and old alike no matter what their baseline level of fitness. A pedometer was invented by Dr. Yoshiro Hatano to motivate people in their walking efforts. It is reported that he chose 10,000 steps at the daily goal because 10,000 steps sounded like an ambitious goal and there was actually a specific word in Japanese for the number 10,000. In fact, many languages have a single word for 10,000. The classical Greeks used a capital letter mu (M)—which means myriad in Greek—to represent 10,000.
So, setting the goal at 10,000 steps per day was a motivating tool rather than an evidence-based objective. Given the wide public acceptance of this step-counting goal without a solid evidence base, researchers have published a number of studies characterizing the relationship between steps, physical activity and health in numerous sample populations.
Some basics about steps:
- The average number of steps per mile is 2,000; so accumulating 10,000 steps per day translates into walking about five miles.
- If you take a brisk walk for 30 minutes (defined as a walking rate of about 3.5 miles per hour), you will cover about 1.75 miles in about 3,500 steps.
- The average number of steps taken per day measured in various groups varies by age, gender and geographic location. For example, one study reported an average of 5,400 steps per day in a U.S. sample of multiethnic women (mean age 54 years) while another reported an average of 18,000 steps per day in a sample of Amish men (mean age 34 years). Western Australians 18 years and older take approximately 9,600 steps per day.
- Step based metrics can include volume (steps/day), step intensity or cadence (mean steps per minute) and sedentary behavior (percent time at zero steps per minute).
Number of Steps per Day and Health Outcomes
Numerous studies have shown individuals who accumulate more steps per day have fewer chronic health conditions and live longer. For example, in an analysis of approximately 3,400 U.S. participants (average age 47, average steps per day 7,564 in men and 5,941 in women) in the 2005-2006 National Health and Nutrition Examination Survey (NHANES), researchers found that increased number of steps per day were inversely associated with weight, body mass index (BMI) and waist girth in both men and women.
In a more recent analysis of a larger NHANES cohort, investigators evaluated the association of daily step count and step intensity with mortality in a total of 4,840 participants (mean age, 56.8 years; 2,435 [54%] women; 1,732 [36%] individuals with obesity) who wore accelerometers for a mean of 5.7 days for a mean of 14.4 hours per day. The mean number of steps per day was 9,124. The mean follow-up was 10 years. Those participants with higher daily step counts had lower BMI and lower incidence of diabetes, coronary heart disease and cancer. Even after controlling for these important differences in baseline health, compared with taking 4,000 steps per day, taking 8,000 steps per day was associated with a 50 percent reduction in the risk of all-cause death and taking 12,000 steps per day was associated with a 65 percent reduction in all-cause mortality.
The Bottom Line
Is it better to walk briskly for 30 minutes five days a week or accumulate 10,000 steps per day? The answer is that it is best to do both.
Most of the data describing the relationship between step intensity or cadence and outcomes is not very robust. This is a difficult measurement to make well in free-living adults. However, it makes sense that those individuals who accumulate the highest number of steps per day (12,000 steps is about six miles), likely walk at a faster pace because most adults have other things to do in the day than just walk. A benefit of accumulating at least 10,000 steps per day is that some of those steps are likely to be at a brisk pace.
But the slower-paced steps also generate health benefits because those steps are replacing sedentary activity.
Even Slow Steps are Better than No Steps
Sedentary behavior is defined as any waking behavior or activity that involves an energy expenditure of 1.0 to 1.5 METS (the amount of energy it takes to sit quietly). Currently, sedentary behavior is likely to involve “screen time” both on the job (sitting using a computer or talking on the phone) or at home (using a computer to shop or interact with friends, watching television, engaging in reading or playing games on a smartphone).
In the 2019 American College of Cardiology and American Heart Association Guideline on the Primary Prevention of Cardiovascular Disease, experts suggest that decreasing sedentary behavior is a reasonable recommendation to reduce the risk of developing heart disease or stroke. Adults in the U.S. spend an average of 7.7 hours per day in sedentary activity. They recommend replacing sedentary time with other physical activity; even light intensity activity is better than sitting.
Overall, the more steps you take on a daily basis the better. A reasonable goal is 8,000 to 10,000 steps per day. Taking a brisk 30-minute walk on most days of the week is a great way to add 3,500 steps to your daily step count and accumulate 150 minutes of moderate physical activity per week.
So whether you are tracking your movement by number of steps or number of minutes, it is simply important to keep moving. Achieving a healthy lifestyle doesn’t happen overnight but rather through a series of small choices throughout your day. It is achieved step by step.
Article provided by Nina B. Radford, MD, Director of Clinical Research and a cardiologist at Cooper Clinic.