Lace up your favorite shoes and take a stroll. It doesn't have to be intense and it doesn't have to be grueling: it just has to get you moving. Even 15 to 20 minute walks can have extensive health benefits, including the immediate rush of getting your blood circulating now, Harvard Health reports. That boost can definitely give you that extra energy you need to take on the world (or that overdue assignment for your boss). Plus, walking will typically take you out of the home or out of the office, refreshing your mind and your body all at once.

Anna Zucker, Tier 3 certified personal trainer at Equinox Fitness in Brooklyn, tells Bustle that she'll pick something like incline walking or an elliptical trainer when she's tired. She says,

"I will still feel good afterwards, but it doesn't require as much mental and physical energy as [weight lifting]. You don't need to think too much about form or recruiting every muscle in your body: just move and sweat and it's over."

So grab your favorite podcast or zone out to your favorite day dream: it'll be done soon!

You might think rowers are intense, and, well, you'd be right. But when you use proper rowing form (think leg push rather than arm yank to start the motion), you actually minimize the amount of energy your body has to use!

And, you don't have to row for long to get a great workout and wake your body up a bit. Try rowing for two minutes, resting for one, rowing for two, resting for one. Rinse and repeat for about 15 minutes and you'll have crushed some serious cardio.

Don't want to commit the energy to a full workout? You don't have to! And if you can't do more than five pushups at a time, that's OK, too. Even if you can't do any pushups with perfect form, you can still do this workout. Just find a stable elevated surface and do them on an incline.

Say you can do max five pushups. Great! Do three. Set a timer for 10 minutes. When the timer goes off, do three more. Repeat for an hour. You'll have done a bunch of pushups by then, without breaking a sweat!

You can do this with bodyweight squats, or lunges, or whatever strikes your fancy: either way, you don't have to commit your tired body to a lot at once, and you get your heart pumping every 10 minutes or so (which will only increase your energy levels!).

What's a pyramid set, you ask? There are many variations, but this one for when you're extra tired is simple enough: start with a moderate weight. Progressively lift more weight (without rest in between). Then, when you've reached your peak weight, go back down in weight until you've returned to your starting weight.

What does this look like? Let's take bicep curls as an example. Start with a moderate weight that you can curl with good form for 12 solid reps. Do those 12 solid reps. In most gyms, weights go up in increments of five pounds. So, without rest, pick the next weight up. Do 10 reps.

Go the next weight higher, trying to hit 10 with good form. If you can't, try to get eight. When you've reached the weight you can only lift with good form for eight reps, go back down the "pyramid" of weights, one increment at a time. Keep trying to crack between eight and 12 reps, which will get harder because even though the weights are getting lighter now, your muscles will be yellin'. When you hit your original weight, you're done!

Do this with two or three exercises, and you're good to go: fast, efficient, and will make you feel like a badass.

Sometimes when you're tired, you want to ease your body through a workout and podcast your way through a brilliant steady state cardio session (like the elliptical above). And sometimes, when you're tired, you want to throw yourself into a workout, hard, because what will wake you up quicker than the adrenaline rush of a heavy lift?

Always do your warm up sets, but the goal here is to recruit as many muscles as possible: focus is key. Pick a compound movement like the squat or deadlift. Since you're tired, if you're working out alone, you might want to avoid heavy bench presses or overhead presses for safety reasons. But the squat or deadlift are sure to wake you up: blast some Evanescence and get after it, and you'll Wake (Yourself) Up Inside soon enough.

Most gyms have a free guest pass system, so today might be the day you grab a friend and bring them with you to your gym (or go to theirs, and grab a guest pass for yourself). Even if you tell yourselves you'll only be there for 15 minutes, there's a lot you can get done with a workout buddy that you can't quite do alone.

Take advantage of having a spotter with you and hit up the bench press, or compete to see who can hold a plank the longest. With any luck, your friend's presence will help you put aside your sleepy and crank up your competitiveness and fun, leaving you with a great workout, good energy, and possible bragging rights.

It might seem daunting to get a workout going when you're tired. And it's always OK to take a rest day! But if you know you want to get after it today even though you're wiped, these workouts will get you where you want to be.