Derek Burnett
Derek Burnett is a Contributing Writer at Bottom Line Personal, where he writes frequently on health and wellness. He is also a contributing editor with Reader’s Digest magazine.
As you begin to plan a workout routine, it’s reasonable to ask yourself just how much exercise you should fit into each day. It can be confusing to sort out what qualifies as exercise, and then to determine if what you’re doing is enough to generate health benefits. As you might imagine, there’s no magic number that every person should adhere to. Partly that’s because we each have our own goals, time constraints, and preferences. But it’s also because of how fuzzy it can get when we try to measure the amount of exercise we do.
If you stop and think about it, “exercise” is kind of a hazy concept. Are you exercising every time you move? Or does exercise have to be deliberate and formal? Do you measure how much you’ve exercised by how many calories you’ve burned? By how many steps you’ve walked in a day? By how much weight you’ve lifted? By how fast you ran or how hard you worked and how much you sweat? Or do you simply measure it in terms of how much time you spent doing the activity? If that’s the case, is it really fair to say that someone who spent 30 minutes strolling along the sidewalk has done just as much exercise as the person who did jiujitsu for 30 minutes?
The truth is, all of those are legitimate ways to quantify exercise. They just might not all be equally useful for providing guidelines to a broad population. That’s why the U.S. Department of Health and Human Services’, in its Physical Activity Guidelines for Americans, uses a simplified, two-dimensional model to measure aerobic exercise (commonly called “cardio” as we mentioned earlier). The first dimension is time measured in minutes. And the second dimension is exercise intensity. Measuring intensity can get very complicated, but the Guidelines helpfully boil it down to this rule of thumb….
Are you really exercising when you’re washing the dishes? What about when you’re squatting on the carpet to play with a toddler? How about walking the dog? Or sweeping your driveway? What about taking out the trash?
All of those could be considered forms of exercise, because you’re physically moving. At its simplest, that’s what exercise consists of…some form of activity in which you are moving your own body in some way. By that definition, nobody (or at least very few people) can truly say they never exercise. To function in society, you’ve got to move around at least a little.
Even though we normally think of exercise as more intense, formal, and deliberate, those baseline, background movements that are the stuff of life should not be dismissed as completely unimportant. Did you have a parent or grandparent who never stopped moving? Chances are, they never did any formal exercise, but while they were awake they always found something to do…clean this, fix that, trim the hedges, pull some weeds, fold that pile of laundry, and on and on until bedtime. And chances are, they maintained a healthy body weight and enjoyed good overall health.
These kinds of “baseline” movements are the minimal recommendation for exercise in the federal Guidelines. At the very least, the Guidelines suggest, move more and sit less each day. Yet as the Guidelines also make clear, you won’t achieve substantial health benefits without also performing more deliberate exercises that get your heart rate up and make you breathe harder. That’s because our modern lives are so sedentary that adding a bit of extra movement won’t be nearly enough to secure significant benefits. And it’s also because sustained moderate-to-vigorous aerobic exercise positively affects your body in ways that simply being on your feet all day can’t. You probably have known people who work physical jobs who nonetheless are overweight or suffer from mobility issues. Although their jobs may be physically demanding, they don’t sufficiently challenge the cardiovascular and respiratory systems on a regular basis.
Zeroing in on the amount of formal exercise to do each day should begin with an honest assessment of how much light-intensity physical activity you naturally have in your life. A typical day for most Americans consists mostly of sitting…in the car on the way to work, at work for eight hours, in the car on the way home, and then in front of the TV. For most of us, our informal exercise occurs in brief, low-intensity bouts between long sessions of sitting. Thanks to the advent of the Fitbit, Apple Watch and smartphone wellness apps, we can now accurately measure how many steps we take each day, which is a very good proxy for light-intensity physical activity. So, “How many steps should I walk in a day?” Generally, recommendations call for 8,000 to 10,000 steps…more if you’re trying to lose weight. If you fall far short of that number, then you’ll want to make up for it in formal moderate-to-vigorous aerobic exercise.
The Guidelines make recommendations for weekly, not daily, amounts of exercise. On rest days, you might do no formal exercise at all, which is fine. Someone else might not feel that they need any rest days, so they’ll divide the weekly number by seven. Other people will load up a few days out of the week with exercise, because that’s what their schedules will allow. Only you can determine a daily exercise amount that works for you within the weekly guidelines.
The number of hours of exercise you must put in each week depends on the intensity of your workouts. As we discussed previously, the Guidelines call for 150-300 minutes (that’s 2.5 to 5.0 hours) every week of moderate-intensity aerobic activity…OR… 75-150 minutes (1.25 to 2.5 hours) of vigorous-intensity aerobic activity. That’s on top of the light-intensity activity you do naturally, plus at least two sessions per week of strength training. Older adults should also mix in balance activities.
If you only ever exercise at one intensity level, it should be easy to simply divide one of those numbers by the number of days you’ll exercise each week to get the number of hours per day you’ll exercise. But most of us don’t exercise that way, so things get murky. We end up with a mishmash of minutes devoted to light-, moderate-, and vigorous-intensity activities throughout our day or week. That’s why it can be overwhelming to try to track your exercise too scientifically. “Let’s see…I probably went up and down the stairs about six times today, and I did a slow run on the treadmill for 30 minutes. In the afternoon I did some stretching and balance work, and then I danced in the kitchen with my granddaughter for five minutes…But was the dancing moderate or vigorous…?”
Rather than get bogged down in such calculations, take the Guidelines broadly. If it works for you, ignore your light-intensity activities and just focus on your formal workouts, classifying each one as having been generally moderate or vigorous, and get your weekly tally. If you’re interested in maximizing your health benefits, go beyond 300 minutes (5 hours) per week, which would come to 50 minutes per day if you were to take one day per week as a rest day.
Whatever you decide, just keeping moving!
