Your question couldn’t be better timed. A new study from the University of Massachusetts, Amherst addressed the issue of how fast you should walk for your health at various ages. The investigation is a corollary of ongoing research aimed at determining the relationship between the number of steps per minute and the intensity of the effort required for walking throughout the adult lifespan from age 21 to 85.
The researchers concluded that for adults from age 21 to 40 walking about 100 steps per minute constitutes moderate exercise, while taking 130 steps or more per minute is vigorous exercise. (140 steps or more per minute equals running). To determine walking speed, the researchers proposed a simple solution – count your steps for 15 seconds, then multiply by four.
To gather data for the study, the researchers recruited 10 men and 10 women for each five-year age increment between 21 and 40. They found the natural walking pace of 90 percent of the recruits was more than 100 steps per minute. To assess how fast they could walk for exercise, the researchers had the participants complete a series of five-minute walks on a treadmill, then rest for two minutes while they calculated the cadence and intensity of the exercise via a portable indirect calorimeter. The participants started the walking test at 0.5 miles per hour and increased their speed at 0.5 mph increments until they began to run, reached 75 percent of their predicted maximum heart rate or reported they were finding the activity “somewhat hard.”
After participants reached “moderate intensity” walking speed of 100 steps per minute, each increase of 10 steps per minute was associated with a boost in energy intensity of one MET (metabolic equivalent). (One MET equals the amount of energy you would burn while sitting quietly. Moderate intensity activities burn three to six times more energy per minute as sitting quietly. Vigorous activity burns more than six METs per minute.)
The researchers now plan to develop recommendations for walking speed and intensity for people older than 40, taking into consideration various factors that could affect walking speed, including gender, height, weight, body mass index, and leg length.
Bear in mind that walking offers much more than its exercise effect. It has been shown to lower stress and prolong life. Among 8,000 men, those who walked two miles a day over 12 years, had a nearly 50 percent lower risk of death. Walking also can help you lose weight and can even benefit your brain: among people age 60 and older, a 45-minute daily walk at a brisk pace of a 16-minute mile has been shown to significantly improve cognitive performance. Another study found that 40 minutes of walking, three times per week, slowed the normal, age-related shrinkage of the brain’s hippocampus.
For the record, one of the benefits of walking is that you can do it indoors (in a mall, for example) or outside. It requires no special skill or practice and is the safest type of exercise, with the least chance of injury.
Andrew Weil, M.D.
Catrine Tudor-Locke et al, “Walking cadence (steps/min) and intensity in 21–40-year-olds: CADENCE-adults.” International Journal of Behavioral Nutrition and Physical Activity, January 17, 2019, DOI: 10.1186/s12966-019-0769-6