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A Cardio Circuit That Will Make You Sweat

Welcome to the day 3 cardio circuit for the SELF New Year’s Challenge! Hopefully you aren’t too sore yet. If you are, don’t worry—it’s completely normal to experience some delayed onset muscle soreness (DOMS) when you strength train, and a little bit of movement can actually help ease those symptoms. Plus, we’ll be working different muscles today, so you won’t continue to tax your achy ones.

For this routine we’re going to step away from strength for a moment and instead really focus on revving up your heart rate—which is part of our overall mission to improve your cardiorespiratory fitness by building cardio endurance. So expect to feel a little breathless as you make your way through these moves.

You’ll get there with a bodyweight circuit that includes cardio exercises and core moves. And while this workout is intense, it’s over quick!

Today’s cardio circuit takes its cues from HIIT, or high-intensity interval training: You’ll alternate between periods of a high-intensity effort with short periods of rest. According to the Centers for Disease Control and Prevention, that means your target heart rate should be between 77% and 93% of your maximum heart rate. (To get a general estimate of your max heart rate, subtract your age from 220. Keep in mind this is only an estimate, and your number may be lower depending on a variety of factors.) Once you know your number, you can track it with any number of smart gadgets, like the fitness trackers currently on the market. If you are a little less into the whole digital thing, you can use the rate of perceived exertion scale, or RPE, which is essentially how hard you feel like you are working at any given time. For the purposes of a HIIT workout, you’ll want to be between a 7–9 on a scale of 1–10, with 10 being an all-out effort. At this level, you shouldn’t be able to manage to speak more than a word or two at a time. (In other words, if you are working out and can carry on a full conversation, you may not be working hard enough.)

For the bonus 60-second burnout, we’ll end with skaters to give you one last hit on some intense cardio work!

Keep scrolling to get the details on how to do today’s cardio and core crusher.

The workout below is for day 3 of the SELF New Year’s Challenge. Check out the full four-week workout program right here. Or go to the workout calendar here. If you’d like to sign up to receive daily emails for this challenge, you can do that here. 


Complete each exercise for the chosen work/rest interval:

I = 30 seconds work, 30 seconds rest
II = 40 seconds work, 20 seconds rest
III = 50 seconds work, 10 seconds rest

Rest 60 seconds between rounds. Complete 3–5 rounds.


  • Modified Jumping Jack
  • Inchworm
  • Mountain Climber
  • Bicycle Crunch


After your last circuit, try the bonus move for 60 seconds.