There are probably many days when you say you don't have time to exercise. Blame your job, your kids or the dog, but life often seems to get in the way. There's just not enough time to fit in at least 30 or 40 sweaty minutes of heart-pounding exercise, so you give up and try again another day.

But the thing is — and you probably kind of know this already — exercise doesn't have to be an all-or-nothing prolonged burst of cardio fitness. It counts if you just move in small bursts throughout the day.

Health experts measure these movements in METs or metabolic equivalents. A MET is the ratio of the work metabolic rate to the resting metabolic rate. One MET is defined as 1 kilocalorie/kilogram/hour and is about equivalent to the amount of energy you spend when you are just sitting quietly, according to the Compendium of Physical Activities. For the average adult, this works out to be about one calorie for every 2.2 pounds of body weight per hour. So someone who weighs 160 pounds would burn about 70 calories an hour just while sitting or sleeping, according to Harvard researchers.

Adding up your MET numbers

Of course you want to pick up your exercise game and burn a few more calories than that. So when you think you can't make it to the gym or spend time on that exercise bike in the spare bedroom, concentrate on your METs. Just sweeping the floor or briskly climbing the stairs can mean serious business. To count as moderately intense activity, the goal is to reach between 3 and 6 METs.

Here's a look at MET expenditure for just a few everyday activities.

  • Sweeping — 3.8
  • Carrying groceries upstairs — 7.5
  • Walking, running, playing with animals — 5
  • Disco or line dancing — 7.8
  • Gardening — 3.8
  • Fast stair climbing — 8.8
  • Brisk walking — 4.3
  • Cooking, washing dishes — 3.3

For a list of nearly everything you do in a day, click on activity categories to find a specific action.

Easy ways to exercise

Woman walking through a parking garage Parking a little farther away is an easy way to sneak more exercise into your day. (Photo: Christopher Gardiner/Shutterstock)

So this means you shouldn't get discouraged when you can't put aside a serious block of time to do a class at the gym or tackle the StairMaster. Just let all this little stuff add up and give yourself credit for parking far away at the grocery store on taking the steps instead of the elevator.

"The research does now show that basically all movement counts, and anything is better than nothing," Michelle Segar, a psychologist and director of the University of Michigan Sport, Health and Activity Research and Policy Center, tells NPR. She says people don't realize all these little exercise opportunities they can easily fit into everyday life.

"I've been astounded that even up until today, very educated people don't know — don't believe — that walking actually 'counts' as valid exercise," she says.

MNN's Starre Vartan offers lots of great suggestions for other great things that also "count" like pacing while talking on the phone or throwing a solo dance party. Her ideas each take just 10 minutes out of your day and — even with our busy lives — we can all find 10 minutes.

Mary Jo DiLonardo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.

What is a metabolic equivalent?
Knowing how to measure metabolic equivalents is an easy way to sneak in exercise and make sure all your movements count.