When J.Lo and A. Rod took to Instagram to describe how they love to start their day with something called “fasted cardio,” the entire world wondered: what the heck is fasted cardio and how much will I suffer while doing it?
Turns out, the answer is pretty simple and doesn’t require an expensive gym membership or personal trainer.
Fasted cardio is simply this: waking up after not eating for hours and getting right to work on your cardio routine, without eating a meal or drinking anything more than water. The idea behind it is that a short burst of extreme cardio (think 20 to 30 minutes) on an empty stomach will burn more fat.
“Fasted cardio is appealing to many of us who are either seeking weight loss or trying to transition our bodies to become more efficient at tapping into our fuel stores,” says Pamela Nisevich Bede, R.D., author of the upcoming Sweat.Eat.Repeat and owner of SwimBikeRunEat.com told Women’s Health. “At first glance it makes sense: By training low or training on empty and without carbohydrate-based fuel in the tank, you force your system to tap into prolific fat stores in hopes of burning fat mass and leaning out.”
Unfortunately, there isn’t a whole lot of science to back up the claim that fasted cardio is any better than, well, ordinary cardio that you can do after a meal or snack. If you do decide to give it a try, experts say it’s important to keep hydrated. And if you find yourself feeling dizzy or faint, stop right away.
Whether you choose fasted cardio or standard cardio, the way to make it work for you (and to burn more calories) is by pushing yourself enough to elevate your heart rate.
According to the Mayo Clinic:
Moderate exercise intensity is 50% to about 70% of your maximum heart rate
Vigorous exercise intensity is 70% to about 85% of your maximum heart rate
Go for a run, jump on a bike, or hit a HIIT class — as long as you’re working hard, all of these cardio options make for excellent morning fitness routines.