Build muscle. Burn Fat. Improve your posture. Strengthen your bones. In singing the praises of strength training, we usually tout the benefits we can see in the mirror, on the scale, or in how our clothes fit.
But there’s more to getting strong than meets the eye. Increasingly, research proves that building muscle delivers systemwide benefits — boons to your body and mind, inside and out.
This is a relatively recent development in the fitness industry. For many years, “exercise” and “cardio” were practically synonymous. Many people didn’t understand the advantages of strength training, and there was a widespread belief that lifting weights made you bulky and slow. As a result, it was a fringe activity and few gyms offered weight rooms like the ones many people use today.
These days, science has broadened its definition of healthy exercise and promotes strength work as an equally essential component of both athletic performance and all-around good health. The American College of Sports Medicine, which has conducted and promoted research on exercise science since 1954, now suggests two or three strength sessions a week in addition to its long-established recommendation of 150-plus minutes per week of moderate cardio exercise.
The reason for this new focus on strength training goes beyond its visual effects. Scientific and anecdotal evidence increasingly points to benefits once associated only with cardio exercise — and to outcomes that weren’t previously associated with exercise at all. Better cardiovascular functioning, stronger resistance to chronic illnesses, and even a more flexible and resilient mind are just a few of the surprising rewards of weightlifting.
So if the promise of more strength alone isn’t enough to get you fired up about lifting on a regular basis, consider these six unsung, science-proven benefits. Together, they create a convincing case for making strength training a central element in your fitness routine.
1. Strength Training Keeps You Healthy
Strong muscles, it turns out, fend off some of the most prevalent chronic conditions. A 2012 paper published in the Journal of Cardiopulmonary Rehabilitation and Prevention reports that mus-cular strength provides measurable protection against heart disease, cancer, hypertension, obesity, and metabolic syndrome. Stronger kids are not as likely as their less-muscular counterparts to develop type 2 diabetes, cardiovascular disease, and metabolic disorders.
Tellingly, these benefits accrue regardless of a person’s weight: Strong people aren’t just healthier because they’re leaner. They’re healthier because they’re stronger.
A 2017 study of women’s lifestyle habits reached a similar conclusion. Among 33,000-plus women studied over a 12-year period, those who strength trained had a 17 percent lower risk for heart disease and a 30 percent lower risk of type 2 diabetes than those who didn’t. Those who combined aerobic activity with weightlifting significantly decreased their risk of cardiovascular disease and type 2 diabetes as compared with those who did aerobic training only.
Where do these benefits come from? “The more you strength train, the more oxygenated blood you push through your system,” says Kaycee Dunfield, national program director for barbell strength at Life Time. “That’s one of the ways your body removes waste, lowers stress, and delivers nutrients to the body.” It’s a head-to-toe housecleaning that makes every system in your body work better.
It’s not how much you lift; it’s how hard you work. A 2012 study found that young men who lifted heavy weights (80 percent of their one-rep max) made the same gains as those who lifted lighter weights (30 percent of their one-rep max) — if they all worked to failure.
For more on this study, visit “Strength in Repetition“.
2. Strength Training Helps You Age Well
Muscle mass peaks around age 25, and as we age we lose it at a swift rate. This gradual erosion adds up until, by retirement age, most of us have substantially less muscle than we had in our youth.
A 2015 study published in the International Journal of Nursing Sciences reports that more than 50 percent of adults older than 80 suffer from sarcopenia — a pronounced loss of muscle mass that can lead to severe restrictions in function and lifestyle. “A high percentage of healthcare costs for seniors arise from the negative outcomes of lean muscle mass loss,” the study authors wrote.
Age-related sarcopenia disproportionately targets fast-twitch muscle fibers, says Jonathan Mike, PhD, a St. Louis–based exercise physiologist. “Those are the bigger fibers responsible for strength and power, as opposed to the smaller slow-twitch fibers, which are more enduring. As you age, you lose the bigger ones first.”
This explains why older people may still be able to walk, even after they’ve lost the ability to run, but it’s also why falls can be so debilitating to people over age 70.
“Fast-twitch muscle fibers help you catch yourself when you fall, so you might bruise, but you don’t break,” Mike notes. “Specifically, it’s important to continue to do heavier strength training as you age to combat age-related muscle loss.”
Some muscle loss as we age is unavoidable, due to diminishing levels of muscle-building hormones and a declining capacity to turn food into muscle. But much of it is preventable — through strength training. A 2010 meta-analysis of 47 studies involving older adults found that rudimentary strength-training programs increased participants’ strength by an average of 28 percent.
“Any exercise is good,” says Mike. “But strength training, especially, helps people avoid falls and fractures, and stay vigorous in general, as they age.”
You don’t need to do marathon workouts: A 2014 study of middle-aged adults found that just 15 minutes of strength training twice a week is enough to stimulate significant strength gains.
3. Strength Training Balances Your Hormones
Several factors influence the delicate balance of our hormones: aging, stress, nutrition, body composition, and insulin resistance, to name just a few. One of the most common expressions of this is “out of whack” sex hormones, specifically low testosterone or high estrogen in men and high testosterone or low estrogen in women. These imbalances can cause low energy, low moods, and low sex drives in both sexes, among other symptoms.
As a result, there’s a growing market for medical treatments such as hormone replacement therapy (HRT), a controversial approach that uses pills or injections to “rebalance” hormones. Taken over a long period of time, some commonly prescribed HRT hormones have been linked to heart problems and other chronic diseases.
When these hormones occur naturally, however, they can work wonders. For that, there’s no better medicine than strength training.
“Weight training is the only activity that creates hormonal changes that help both men and women burn fat while maintaining or gaining muscle,” says Jade Teta, ND, an integrative physician in North Carolina and longtime fitness coach.
In both sexes, he explains, strength training stimulates the release of human growth hormone, which aids in building muscle and burning fat. It also increases insulin sensitivity, which helps control blood sugar and reduces the risk of type 2 diabetes.
Strength training has also been shown to help regulate sex hormones — testosterone and estrogen — especially as men and women get older. As men age, their testosterone level often drops relative to their estrogen level, which can affect muscle growth, energy levels, and sexual function.
Women commonly produce less estrogen as they grow older, which can increase the risk of osteoporosis, heart disease, and general hormone dysregulation.
Strength training has been shown to stimulate production of these sex hormones and help rebalance them for both men and women.
If you want a healthy hormonal profile without using drugs, strength training — independent of other lifestyle and nutritional changes — may be your best bet, says Teta. The hormonal effects can “produce the changes and the look of a healthy, fit physique.”
4. Strength Training Keeps You Lean
People typically think of strength training as a muscle-building activity: lift weights, pack on muscle. But research is increasingly finding that it’s an effective fat burner as well.
Aerobic training — low-intensity, repetitive exercise like jogging or cycling — can help you lose weight, too, says Brad Schoenfeld, PhD, CSCS, a leading expert on body transformation. “But aerobic exercise doesn’t help preserve muscle mass while you’re losing weight,” he explains. Some of the weight you lose during aerobic training will be in the form of lean muscle mass.
Muscle tissue is the engine that drives fat loss — so you want to retain as much muscle mass as you can if you’re trying to get leaner.
The best way to do that is hitting the weights: “Strength training helps you maintain, and even gain, muscle mass, making it a really important factor in fat loss,” says Schoenfeld.
In addition to preserving muscle, which itself burns fat, the anaerobic effects of strength training contribute to fat burning through a process known as excess postexercise oxygen consumption, or EPOC. An exerciser consumes additional oxygen following a strength workout, and this increased oxygen use — which Schoenfeld says can last up to three days, depending on the intensity of your workout — burns more calories and elevates the metabolism beyond the body’s non-EPOC state.
Additionally, following a strength session, muscles remain slightly contracted, a state that requires more energy to maintain than when they are relaxed. The body also gets to work repairing damaged tissues by shuttling nutrients from the digestive system to the muscles. These postworkout functions need fuel, meaning your body will burn calories long after you’ve finished lifting.
Just how many calories can a single strength session burn? It’s a hard question to answer, both generally and specifically, because many factors contribute, including fitness level, body composition, and workout difficulty.
Luckily, says Schoenfeld, the caloric numbers don’t matter if you lift consistently in a way that suits your body. Three or four sessions a week over time will make a difference.
Lift early and often: A 2008 report endorsed by the American Academy of Pediatrics suggests that strength training can have profound benefits — including increased bone density and fewer injuries — for adolescents and preadolescents. To get your child started, begin with body-weight training, preferably under the guidance of a coach. Once the child can control a body-weight movement, it’s OK to gradually add external loads.
Learn more at “Expert Answers on Safely Strength Training for Kids“.
5. Strength Training Tones Your Gray Matter
Mounting research is showing that strength workouts may do as much for your brain as they do for the rest of your body.
A study of identical twins found that leg strength, more than other lifestyle factors assessed, was the best predictor of cognitive function 10 years later. The research, published in 2015 in the journal Gerontology, looked at 324 female twins ranging in age from 43 to 73.
Generally, the twin with the stronger legs at the start of the study maintained her mental abilities and had fewer age-related brain changes than the twin with the weaker legs. A stronger body, it turns out, makes for a stronger brain.
Numerous other studies suggest that strength training can help prevent, slow, or even reverse the progress of many common mental and cognitive ailments. Strength-training regimens have proven life-changing by alleviating depression, for example.
Older women develop fewer memory-impairing lesions on their brains when they perform basic, twice-weekly strength-training workouts, according to a 2015 study published in the Journal of the American Geriatrics Society. And people with MCI — mild cognitive impairment, a precursor to dementia — see a boost in brainpower when they pump iron, Australian researchers found.
Even a single bout of strength training can support memory, according to a 2014 study. Strength work, researchers suggest, increases salivary alpha amylase, a biomarker for stress and arousal that may increase brain activity. So even healthy brains get a near-instantaneous lift from hitting the weights.
In nearly every study, challenging strength workouts led to more improvements in brain functioning: The tougher the lifting sessions (whether lifting heavy or performing more reps of a lighter weight), the more the brain benefited.
Scientists don’t fully understand why and how these changes occur, says Teresa Liu-Ambrose, PT, PhD, an expert on physical activity and cognitive neuroscience at the University of British Columbia in Vancouver. But one theory argues that strength training releases insulin-like growth factor 1 (IGF-1), a protein that promotes neuronal growth. Another possibility: Systemic changes in the metabolic and cardiovascular systems create a healthy environment where the brain thrives.
“Resistance training is beneficial in reducing cardiometabolic risk factors, which are associated with cognitive impairment,” says Liu-Ambrose. “So resistance training, like aerobic training, benefits the brain by reducing chronic conditions that negatively impact the brain.”
Forget performing exercises for every tiny muscle. The best, most time-effective way to build muscle, says Brad Schoenfeld, PhD, CSCS, is to perform compound exercises that involve movement at two or more joints. Some great examples: squats, deadlifts, lunges, presses, and rows.
6. Strength Training Can Inspire You
With all the focus on the physical rewards of exercise, it’s easy to overlook its inspirational power. For some people, strength training is a spiritual, as well as physical, discipline — and one that’s no less powerful or resonant than meditation or the martial arts.
“People explore the limits of their abilities and have an opportunity to express intensity when they strength train,” says Jolie Kobrinsky, owner of Prime Personal Training in Monterey, Calif. That makes some sessions personal triumphs: You lift a weight you’ve never lifted or pull off a move you’ve never done. In other sessions, she says, “you have to confront feeling weak in front of others. You fail and try again.”
In her years as a trainer, Kobrinsky has seen these daily struggles in the gym add up to profound personal transformations. One recent client, who’d suffered from childhood arthritis, found new assertiveness — along with improved mobility and strength — after a few months in the gym. “She stood up to her mother, which she’d never done before,” recalls Kobrinsky.
“She had a children’s book published. She transformed herself into a stronger person — physically, mentally, and emotionally.”
This doesn’t happen to everyone, she points out. “But sometimes, a physical shift manifests into a deeper [emotional] one.”
As rewarding as it can be to help people get fitter and healthier, it’s changes like these that Kobrinsky finds most fulfilling. “I wouldn’t keep doing this work if I didn’t believe it had greater ramifications,” she says. “When you try something difficult and prevail, you have a palpable experience that translates into your life.”
How to Overcome Weight-Room Fears
The weight room — jammed with odd-shaped iron and strange-looking machines — can appear intimidating. Bust through your first-timer fears by following these four simple rules:
• Don’t try to build Rome in a day. You wouldn’t try Rachmaninoff your first day at the piano, right? So don’t worry about advanced exercises and big weights your first day in the gym. “Start with something that makes you feel successful,” says Jolie Kobrinsky, owner of Prime Personal Training in Monterey, Calif. Do less than you think you can and leave the gym glowing, not exhausted.
• Keep it simple. The strongest people in the world practice variations on basic moves: pushups, squats, lunges, rows, planks. Those multijoint movements will form the backbone of your workouts, now and forever. “String four or five of those moves back to back, do 10 reps of each, rest, and repeat,” says Kobrinsky. “Presto — you’re a weightlifter.”
• Show up. For the first few weeks, carving out the time and energy to get to the gym can feel like a Herculean task. But fear not. If you’re consistent, you’ll accrue enough little successes after three or four weeks that you’ll start to wonder how you ever went without it. “Pretty quickly you wake up your inner superhero and start to feel like you can do anything,” says Kobrinsky. “That’s when strength training gets really exciting.”
• Don’t go it alone. If you’re unsure about where to start, or simply need some added motivation and accountability, there are many options: Hire a coach or personal trainer, find an accountability group (in-person or online), or enlist a friend or partner as your workout buddy.