Do your workouts need a little boost? Maybe your cardio sessions are becoming a little too easy. Don't get me wrong, it's definitely a good thing to not have that "I think I'm gonna die" feeling after a workout! But in order to keep moving toward your fitness goals, you need to progressively challenge yourself as you get stronger.
So here's a little tip: try adding weights to your wrists. By adding weight to your arms during a cardio workout, you'll raise your heart rate faster because you're using more muscles. If your workout doesn't already include arm movements, you can customize and add some bicep curls, tricep extensions, etc.
Wrist weights come in many different brands, sizes, and weights. You can find them online (even at amazon.com) or in any sporting goods store. So get moving!
