You probably already know that hitting the weights at the gym or doing bodyweight exercises makes you stronger and fitter. But what many people don't realize is that strength training does far more than that for both your body and your mind.

"I'm actually so surprised when women still admit to me that they don't do any weight training," says Los Angeles-based celebrity trainer and exercise physiologist Michelle Lovitt. "The benefits go so far beyond getting big muscles. I encourage everyone to stray away from only heading for the cardio machines."

Read on for five incredible effects of weight lifting that will help you finally ditch the excuses for avoiding the weight room. And if you're already a lifter, these perks just might make you even more excited to hit the gym.

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Your metabolism gets a boost

Having more muscle turns your body into a fat-burning machine. "Building muscle mass helps your body burn fat more efficiently at rest," says Lovitt. "And you just don't develop muscle through cardio the way you do when you are doing strength training."

In other words, the more muscle mass you develop through bodyweight exercises or by using weights and other resistance equipment, the more calories and fat you are blasting even when you're just sitting around watching Netflix or glued to your desk chair. (The amount of calories you burn at rest is referred to as your basal metabolic rate, or BMR.)

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You protect your bones

Want to stay active and injury-free all throughout your life? Weight training is an essential Rx. A growing body of research shows doing weight-bearing exercise can help prevent bone loss (or potentially even build bone), and in turn, reduce your risk of osteoporosis and possible fractures down the line. "In a way, you're really offsetting aging," Lovitt notes.

Lovitt has a 70-year-old client who thought she would be too fragile to participate in weight lifting. Two years later, "she is the epitome of what strength training can do for an older person," Lovitt says. "She has lost weight and body fat, but she is also much more muscular and her balance and stability are miles from where they were, so she is better able to live her life as safely as possible."

Your sleep may improve

Resistance training is a natural remedy for sleep issues. One small study in the Journal of Exercise Physiology Online found that elderly people who practiced moderate-intensity resistance training for 12 weeks had better sleep quality compared to older folks who stayed sedentary over a six-month period.

What's more, you may notice you have better energy throughout your day when you take up weight training.

The caveat: Doing serious power lifting (think: bodybuilders) or intense weight lifting close to bedtime could have the opposite effect and disrupt your sleep or leave you worn down, Lovitt points out.

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You stay sharp

Building up muscle strength may lead to better brain function. In fact, research has shown that starting resistance training may help older adults with mild cognitive impairment (MCI) improve cognitive function over time. A 2016 Australian study divided 100 older men and women with MCI into two groups. One group was assigned to do resistance exercises twice a week for six weeks, while the other was instructed to perform seated stretching and calisthenics instead. The folks who built muscle by strength training also built their brains: They performed better on cognitive tests than the stretching group, and scans showed growth in specific areas of their brains linked to mental benefits. 

“The stronger people became, the greater the benefit for their brain,” lead author Yorgi Mavros, PhD, an exercise physiologist at the University of Sydney, said in a press release at the time.

You zap stress

While most available research on the effects of exercise on mood focus on aerobic activity, there are studies that zero in on resistance training that have found it can be a worthwhile intervention for people with anxiety.

"I started hitting the weight room at a time in my life when I was incredibly stressed out in grad school and needed an outlet," says Anna Laura Sommer, 27, a personal trainer and health coach in Philadelphia. "It really helped me not only get rid of so much of my worry, but it also helped me become a part of a community."

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Lovitt echos this sentiment: "I work with busy moms, CEOs, and celebrities with insane schedules who tell me the time we spend weight lifting is the best stress reliever for them," she shares. "They channel their stress into the weights, and the powerful movements and exertion really allow you to release something both physically and emotionally."