All you need is two dumbbells to perform this metabolism-igniting workout. 

With no rest between each exercise and just 30 seconds of rest between rounds, this circuit will fire up your heart rate. Combine the non-stop pace with some muscle-building combos, and that means your metabolic engine will be revving. (For more workouts that will challenge your body and heat up your metabolism, check out Maximus Body.)

Dumbbell hammer curls plus forward lunges are a classic total-body combo because not only are you working legs and arms, but the constant motion adds a cardio element.

Adding a leg lift to a dumbbell pushup increases level of difficulty by requiring a stronger core. The dumbbells allow for a neutral wrist during pushups.

Dumbbell triceps kickbacks help sculpt the back of the arms and also work your entire backside as you hold the hip hinge position.

Another upper and lower body combo, the dumbbell split squat to shoulder press, is going to hit up the quads and glutes while simultaneously assaulting the shoulders.

This is a simple, but challenging workout that is guaranteed to give you a total-body burn.

  1. Dumbbell hammer curl plus forward lunge, 5 reps per side
  2. Dumbbell pushup with alternate leg lift, 5 reps per side
  3. Dumbbell triceps kickback, 5 reps
  4. Dumbbell split squat to shoulder press, 5 reps per side

Rest 30 seconds. That's 1 round. Do 4 rounds.