How should I get into weightlifting

A good warm-up preps your body for the increase in activity and a cool-down allows your heart rate to return to a normal resting rate, says Wu. Don't cut corners here: "Muscles that have not been accustomed to strenuous activity for sometime will experience some form of DOMS (delayed onset muscle soreness), which basically means you are going to be tight and achy for 24-72 hours after your workout," says Sikorski. (You may also experience this is you work out regularly but up your intensity.) "A proper cool-down session can reduce some of this soreness."

6. And spend a few minutes stretching.

Speaking of tightness, stretching is especially important when you're getting back into a fitness routine. A good warm-up includes dynamic stretches. And when you are done working out, finish with some more stretches—like these.

7. Take it slow and focus on your form.

Quality trumps quantity, especially when you're just getting back into fitness. "Slow down," stresses Sikorski. "Be deliberate and conscious of your movements. Take the time to focus on your form, on your breathing, on your control." This is extra important because proper technique and form are crucial for avoiding injury, adds Wu.

8. And don't forget to listen to your body.

Chances are, your body is going to let you know that it's working hard, but learn the difference between hurts-so-good and hurts-not-so-good. "If something feels weird or gives you pain, stop doing whatever that is," says Sikorski. "There's actually a not-so-fine line between muscle discomfort from a good workout, and pain lets you know something’s not right."

9. Don't skimp on sleep.

"Working out is 'work'—it takes more time and energy, so you might feel fatigued initially because you are burning more calories and the body is trying to adapt to the increased stresses in the tissues," says Wu. "If I'm so exhausted that I'm walking around like a zombie, I might opt for some more sleep on a particular day," she adds. So it's OK to tuck in a little early and hit snooze on some days...your body will thank you.

10. Find a friend who keeps you motivated.

Workout buddies unite! "Find a friend who is already working out and has a routine. That person can be a key motivator," says Sikorski. If you'd rather share the starting line, find a friend who is also looking to get back into a regular routine. "Together, you can keep each other motivated and accountable," adds Sikorski.

11. And, finally, set goals to keep you focused.

Sikorski recommends setting a S.M.A.R.T. goal–specific, measurable, attainable, realistic, and time-sensitive. "What is your run a 5K? To feel stronger?" asks Sikorski. Start there, then create a plan.

Remember, it's OK to feel overwhelmed at times. Don't get discouraged, you got this!