We have a lot of active people in our neighborhood. On any given day you will see joggers and walkers, a mom or dad pushing a stroller or a happy dog with his owner. People are walking briskly or even jogging. Some days though, I see a few people who are just ambling slowly down the sidewalk. They seem to lack a certain intensity or sense of purpose. Maybe they feel weak that day, maybe they just have a low-keyed personality or maybe they just cannot walk much faster for very long.
I have considered stopping them and saying, "Pardon me, but I noticed you walk slowly. Do you do this on purpose? Can you walk any faster or is this your top speed? Did you know that how fast you walk is a good predictor of your state of health? Do you feel ok?" But I'm sure they would respond not only with shock and surprise but may even pull out a cell phone and dial 911.
It's true. Walking velocity or speed (the distance you cover in a period of time) is a good indicator of your health and likely what's in store for you in the future much like blood pressure, cholesterol and body fat levels. Walking speed predicts dependency, mortality and institutionalization in people over the age of 70*. People over the age of 65 who walk more slowly than normal have a much higher incidence of falling (and by the way, the timing at stoplights to cross the street is based on normal walking speeds!). This fact is important because falls are the sixth leading cause of death for people over the age of 65. Walking research consistently reports decreasing walking velocity with advancing age. And, we have as a society accepted walking slowly as normal for older adults. But, is it a normal consequence of aging or does it happen for other reasons and can you prevent or delay the onset?
How fast you walk is partly determined by your cadence or the number of steps you take per minute. Cadence does not vary much as you get older and is fairly consistent among adults at 117 steps / minute. What changes is your step length. As you age, if you aren't careful, your velocity will decrease because your step length decreases. This begins in your 30s and 40s. You move slowly taking frequent, small steps and this is when the risk of falling goes up dramatically.
But, to be fair we all walk at different speeds or what is termed our free speed. I may choose to walk slowly because I want to enjoy the breeze and sound of the ocean on a sparsely populated beach at sundown. But, I still have a top speed or a higher gear I can use and sustain for an extended period of time. Top speed is walking briskly but not as fast as you can (which is maximum speed). It's kind of like a first gear/second gear relationship.
Your body is exceptionally good at using only what it needs in terms of energy, muscles and joints. It adapts in either a positive or negative way. As you age, if you do not maintain your top speed by consciously stressing your body, then your top speed gradually declines toward your free speed. Soon, top speed equals free speed.
Once top speed equals free speed, you will only get gradually slower and more feeble until one day you fall. One of the keys to keeping yourself healthy is to maintain a gap between your top speed and your free speed. Here's how to do it:
Walk about 100 meters at your normal free speed. Pick a number on a scale of 0 -10 (where 0 is super easy and 10 is super hard) that represents the degree of difficulty of the walk. Let's assume you choose 2/10 or quite easy. Now, walk 100 meters at your top speed. Pick a number again. Let's assume the number is 8 or fairly hard. The degree of difficulty difference is 6 (top speed - free speed). The larger that number gets, the worse for you. You want your top speed effort to feel almost as easy as your free speed effort. This will occur only when your body is used to moving at top speeds and it gets that way only from walking at top speeds.
Top speed walking is best done by focusing on taking a little longer step than you are used to taking. The easiest way to do this is to walk uphill or on an incline on a treadmill for a few minutes a day (just starting out) building up to 15- 20 minutes per day. Remember, you need a longer step length, not more steps per unit of time.
Walking speed is a critical marker for your future youth, but one very few people know about. Because our society is so sedentary, this physical ability erodes slowly over time, usually beginning in your 30s and 40s, eventually leaving you at risk for serious injury and even death. And, it is very simple to fix.
No matter your age, get up and get walking.
Make today count.
Doug Kelsey
Author. Teacher. Therapist.
* Reference: Woo J, Ho S C, Yu L M "Walking speed and stride length predicts 36 months dependency, mortality, and institutionalization in Chinese 70 and older" JAGS, 1999 Oct; 47, 1257-1260
