Find out if you're doing as much as you should be.
But if you're trying to figure out how many minutes on the treadmill you'll need to clock before seeing a difference on the scale, you should know that there are a bunch of factors at play here.
However, while it’s tough to give a straight, no-fuss answer, it is possible to come close to nailing down a cardio quota for the week.
Before we get there, remember the golden rule of weight loss: You need to be doing enough cardio to go into a calorie deficit, says Cassandra Forsythe, Ph.D., R.D., C.S.C.S. In other words, you’ve gotta be expending more calories than you’re taking in. So if you’re not already tracking the cals you’re consuming, start doing that with an app like MyFitnessPal, where you can also enter your other personal data (height, weight, goals, etc.) so it can create a calorie plan for you.
Now, cardio. For weight loss, the National Institutes of Health recommends at least 30 to 45 minutes of moderate-intensity exercise three to five days a week. But you can maximize your sweat sessions for efficiency if you alternate between high- and low-intensity workouts each day, says Forsythe. She suggests aiming to work out five days a week, alternating the intensities each day and working out no more than two consecutive days to allow your body time to recover.
For the record, high-intensity workouts are usually ones where you’re at 70 to 90 percent of your max heart rate, according to the American Heart Association. (That means it feels like you can barely say more than a few words at a time.) Moderate-intensity exercise is at about 50 to 70 percent of your max heart rate, and allows you to say a couple of sentences while you're working.
On days you’re ready for more action (or your schedule is tight), amp the intensity of your cardio workout on a machine by adding in some interval training, says Forsythe. You’ll torch more cals in a shorter amount of time. For example, run (or bike) as fast as you can for one minute, then recover for one minute at a slower pace, and repeat that for about 15 to 20 minutes. You can also step off the machines for some bodyweight circuits. Forsythe suggests exercises like burpees, speed skaters, jumping jacks, plank jacks, and mountain climbers, completing 30 seconds of each consecutively with no breaks, then break for 30 to 60 seconds, then repeat the whole sequence a few times until you’ve hit about 20 minutes.
If you've got extra time, aim to fit in some longer, lower-intensity exercises, like walking or jogging, biking, or using the elliptical. Note: You’ll have to do these longer to burn more cals, at least 30 to 45 minutes at a time, says Forsythe. But don’t dismiss these low and slow options. According to The National Weight Control Registry, 94 percent of people who successfully lost and kept off their weight had increased their physical activity, most of them from walking. (And most of them exercise about an hour a day, so if you’re walking, aim for closer to 60 minutes. If you’re jogging or running, you can call it quits sooner.)
Basically, the amount of cardio you have to do to lose weight is super flexible per your schedule and your preferences. No matter which ways you choose, cardio will help you shed pounds and keep them off.