Grab Your Dumbbells and a Towel, Because This 45-Minute HIIT Workout Heats Up Fast

HIIT workouts are high exertion, Karisa explained. Get your body prepped with a dynamic warmup to slowly raise your heart rate, loosen up your joints, and increase blood flow to the muscles. For this warmup, you’ll do each exercise for 30 seconds, resting for 10 seconds in between. Repeat the circuit three times, for a total of 10 minutes.

• Jumping jacks
• Squats
• Forward lunges
• Hamstring and groin stretch (hold your ankles and straighten your legs to stretch your hamstrings, then sink your hips and lift your chest for the groin)
• Butt kicks

• Rack a set of weights at your shoulders and drop into a squat position, with your feet roughly hip-distance apart, as shown.
• Immediately jump into a wide jack position (as you would during jumping jacks), while sending the dumbbells overhead.
• Jump back into the squat position as you bring the weights back down to your shoulders.
• Repeat for 40 seconds.

• Place a mini band on the floor as a marker.
• Stand on one side of the band and begin jumping over it, moving left to right and back again. (If this is too difficult, you can hop over the band with a single leg.)
• Repeat for 40 seconds.

• Start by standing in a split stance, with your left foot forward and your right foot behind you. Hold a set of weights at your sides.
• Drop into a split squat, bending both knees at a 90-degree angle. Perform a bicep curl, bringing the weights toward your shoulders, as shown.
• Hop and switch legs mid-air, landing with your right foot forward and left foot back, then immediately drop into a split squat. (If this is too difficult, simply do a reverse lunge in place of the jump.) Perform a bicep curl.
• Repeat for 40 seconds.

• Place a mini band around your ankles, and stand with your feet shoulder-width apart. Put a slight bend in your knees, as shown.
• Keeping your knees in line with your toes, hop forward and back again.
• Immediately move your right foot out to the side to touch the ground, then back. Do the same with your left foot.
• Repeat for 40 seconds.

• Loop a resistance band around both feet so you’re standing on it. Stand up straight with both hands behind your head.
• Bring your right knee wide and up, at the same time dropping your right elbow so the two meet in a side crunch, as shown.
• Return to starting position, and repeat with only the right leg for 40 seconds.
• Alternate sides with each round.

• Place a mini band just above your knees. Stand with your feet slightly wider than your shoulders, holding a set of dumbbells at chest level.
• Drop into a squat position, pushing your hips back and bending your knees until your thighs are parallel with the floor, as shown.
• While holding the squat, focus on keeping your back flat and your chest elevated, and alternate punching the weights away from your chest at a quick pace. (You can see this movement in a similar squat here.)
• Repeat for 40 seconds.

• Run in place, driving your knees up with maximal intensity for 20 seconds.
• Immediately drop into a squat and hold for 10 seconds.
• Repeat for a total of six rounds.

A cooldown is especially important after a workout as strenuous as HIIT to safely slow the heart rate, reduce muscle soreness, and maintain flexibility, Karisa told POPSUGAR.

Take five to 10 minutes to do some lower-intensity movements, such as lateral lunges and Cat-Cows, as well as some static stretches, holding each for at least 30 seconds to properly recover from your efforts. Some good moves include a standing quad stretch, crossbody shoulder stretches, and seated forward bends – find a more comprehensive list of stretches here.