This page is about lifting weights, also known as resistance training. Below, I will layout a variety of reasons why you should lift weights/do resistance training if you are able to.
If you have any sort of health condition that might be dangerous or exacerbated by lifting weights, talk to a doctor and a physical trainer before engaging in any heavy lifting.
Weightlifting BenefitsThe Milonyx Dictionary
Aerobic training: Uses primarily the aerobic energy generation system, which kicks in in longer bouts of exercise, like running or cycling for distance. Applies primarily to circuit training, not so much to bodybuilding or powerlifting particularly.
Anabolic-Androgenic Steroids (AAS): Compounds that act as hormones in the body, giving the effects of anabolic (muscle building) and androgenic (male sex characteristic producing) hormones, like testosterone and DHEA. When a person is called "natural", they are (ostensibly, allegedly) free of steroids and other PEDs that are banned in competitive sports like bodybuilding and powerlifting, though these lines change all the time with new compounds and supplements. Virtually all professional bodybuilders, as well as powerlifters and other athletes (Olympic lifters, cyclists, swimmers, seriously, everyone at the upper levels is doing something), use some steroids or other PEDs for various purposes like improved muscle growth, faster recovery, and more fat loss. Many people falsely claim they are not using steroids. It can be extremely risky to use (risks include balding, reduced testicle size, increased aggression, overuse injuries, libido issues, heart problems, liver problems, and death), they require careful preparation, planning, and knowledge to use responsibly.
Anaerobic training: Uses the anaerobic energy system (ATP and glycogen) to generate power over shorter periods, about 2 minutes or less.
Bodybuilding: The act or process of improving your body composition through muscle growth and fat loss, typically by lifting weights and doing resistance exercises. It is also a competitive sport with many professionals worldwide.
Muscular hypertrophy: The technical term for your muscles getting bigger by increasing the size of the cells. Achieved through resistance training and higher intensity, shorter duration exercise (compare Olympic sprinter physiques to Olympic marathoners). The holy grail of bodybuilding, alongside body fat minimization.
Powerlifting: A style of training emphasizing maximal weight lifted within competition rules in the squat, deadlift, and bench press. Typically trains with lower rep ranges (often under 5) and heavier weights. Usually, powerlifters have more muscle and more fat than bodybuilders, since they only care about lifting heavy weights, so they look "bigger and softer".
Programming: The organization of a lifting program. How many days per week, how intense, which exercises, what order, what weight scheme, planning deloads to recover, etc. Endless ink has been spilled over how to best program your routine.
Progressive overload: A fundamental principle of weight training, that you must continually overload the muscles with heavier weights, more reps, more sets, or a faster tempo. If you used the same routine with the same weight forever, you'd stall at a certain level of strength and size, so you must continually work harder.
Resistance training: Physical exercise utilizing resistance against muscle movement. Includes lifting barbells, dumbbells, using resistance bands, and bodyweight exercises like pullups, pushups, and dips.
Strength training: More or less synonymous with resistance training, though sometimes used to emphasize "strength" rather than "size", or to refer to training for strength or power rather than hypertrophy or conditioning.
Training load: You will see phrases like "80% of 1RM". RM stands for repetition maximum, so 1RM is your "one rep max", or how much weight you can lift in one single rep. Training loads are typically described as percentages of a person's 1RM, so that programs can be tailored to individuals easily and consistently. 0-30% RM is often described as "low intensity" and 70-100% RM as "high intensity".
Weightlifting (AKA Olympic lifting): A sport based on maximal weight lifted in the clean and jerk and snatch, the two Olympic lifts. More akin in training to powerlifting, with heavier weights and lower reps, but professional weightlifters are sometimes shredded, sometimes softer.
Body composition is the relative proportions/percentages of different types of tissue in your body - fat, bones, water, lean muscle mass, organs, etc. The ones we're interested in as far as aesthetics and health go are primarily body fat (visceral, around the organs, and subcutaneous, beneath the skin) and lean muscle mass, as the weight of your bones and other organs change very little, and water weight fluctuates around an average range.
Pro bodybuilders like Kai Greene have basically maxed out their lean muscle mass, dropped their fat to as low as possible, and when they look that shredded and defined, they've dropped all their water weight as well. The extreme opposite of this, with high body fat and little muscle (mostly in the legs to support the weight), is morbid obesity. The less extreme opposite is what is referred to as "skinny fat". He's not fat, really, but he's not just skinny, nor is he muscular... so, skinny fat. For an average American who doesn't work out or do physical activity at all and doesn't really watch what they eat super carefully, this is probably the best hope.
So why are we talking about body composition? Well, body composition is what separates those jacked guys at the gym and the fit, big booty Instagram models from the average person. When people talk about hitting the gym to "get toned", to "get fit", to "look good", to "lose some weight", to "build a better body" - they're all really talking about the same thing, which is increasing muscle mass and reducing body fat. The sport-specific to doing that as well as possible is bodybuilding, not weightlifting (Olympic weightlifting) or powerlifting (maximizing weight lifted in a squat, deadlift, and bench press). All three sports use similar tools and techniques, but they are not the same and will not produce the same results. They will all give you the health benefits of lifting weights, but the outcomes and training styles are significantly different.
So what can you expect as a natural lifter (i.e. not using steroids) in terms of progress and aesthetic improvement? Does lifting work? I would argue that it definitely does, but you tell me.
If you think the after pictures look a lot better than the before pictures, well, I agree with you, and the transformations were all achieved by lifting weights, most of them in less than 2 years, some in just a few months. If you want to look more like this guy and less like this guy, or more like her and less like her, then lifting weights is the most efficient way to get you there.
Alright, so lifting helps you look better, but what about your health?
The health benefits of lifting weights/resistance training are numerous, ranging from improved flexibility and increased bone density, to reduced subcutaneous fat and lower risk of physical injury.
Strength training prevents loss of bone mineral density with age, as well as reducing fall risk, reducing insulin resistance, and reducing intra-abdominal fat (IAF not good, folks! very bad!). This helps reduce the risk of osteoporotic fractures. A review of the lifting/bone density literature finds that it is likely that resistance training increases bone mineral density and definitely increases balance and muscular strength, which reduces the risk of falls. A review of 7 RCTs on patients with chronic kidney disease finds that progressive resistance training improves strength, muscle mass, and health-related quality of life.
Low back strengthening with lumbar extension exercises helps reduce pain for many with chronic lower back pain, a benefit that was found to occur with one set of 8-15 reps per week! A systematic review finds that strengthening exercises are among the most effective exercises to reduce chronic low back pain. Another study measured hormone responses of older men to a 16-week lifting regimen - they lifted 3x a week, for about an hour per session, doing a passable excuse for a routine (you could design better after reading a book and some articles about programming), and had ~40% increases in upper and lower body strength, as well as gaining a couple kilos of muscle and losing a couple of fat, on average.
Once or twice weekly lifting in older adults resulted in similar strength gains and physical improvements as 3x/weekly lifting. A meta-analysis of the relationship between training frequency and muscular strength gains found that, while training more frequently (3-4x/week) did result in more strength gains, the effect wasn't that large: "Effect sizes increased in magnitude from 0.74, 0.82, 0.93, and 1.08 for training 1, 2, 3, and 4+ times per week, respectively."
The short version of all that is that if you're really pressed for time or just really don't want to lift a lot, you can get a lot of the benefits of resistance training just by working out once or twice a week for an hour or less.
Interlude: You might have read the above and become confused - how can you lose fat and gain muscle at the same time? Well, you can, and in fact, most people will if they start lifting after never having done so before. Have you ever seen a fat person start hitting the gym and losing weight? What do you think is happening when they get visually/physically smaller (losing subcutaneous fat), can lift more (getting stronger, which correlates highly with muscle cross-sectional area), and start growing muscles (increased cross-sectional area)? Don't buy the BS - you can lose fat and gain muscle at the same time!
Getting Old? Lift!
Progressive resistance strength training is found to improve physical ability among older adults (things like getting out of a chair, getting into and out of a car, going up and downstairs, etc.). A review on balance interventions finds weak evidence of moderate effectiveness of "strengthening exercises" in improving balance in those aged 60+. Progressive resistance exercise found to reduce resting blood pressure in the meta-analysis of RCTs.
You need not just take it from me; here's a statement from recommendations made by the American Heart Association in 2007:
Prescribed and supervised resistance training (RT) enhances muscular strength and endurance, functional capacity and independence, and quality of life while reducing disability in persons with and without cardiovascular disease. These benefits have made RT an accepted component of programs for health and fitness.
participants in combined strength and aerobic training regimens improved to a reliably greater degree than those in aerobic training alone (0.59 vs. 0.41, SE 0.043, n=101, p <.05)
[on whether aerobic fitness training can have a robust and beneficial influence on the cognition of sedentary older adults] The animal literature [suggest yes], but a perusal of the literature on human aerobic training appears more equivocal. The answer provided by the present analysis is an unequivocal yes. Fitness training increased performance 0.5 SD on average, regardless of the type of cognitive task, the training method, or participants’ characteristics.
See this figure from the "review of mental health benefits" study linked below, for a comparison of improvement in cognition between aerobic only and aerobic + strength training. Adding strength training improves the benefit of 50% over aerobic training alone.
Resistance training improves metabolic health in Type 2 diabetes in the systematic review. Another systematic review finds no difference in the treatment efficacy of resistance training and aerobic training (both good!) in Type 2 diabetes. Strength training reduces the risk of type 2 diabetes and cardiovascular disease in women independent of aerobic exercise.
Resistance training improves strength, balance, and motor symptoms in Parkinson's in the systematic review. A different review finds evidence of benefit in walking capacity, but not most other physical indicators in Parkinson's. Strength training significantly improves muscle strength, mobility, fatigue symptoms, functional capacity, and quality of life in subjects with Parkinson's and MS. Twelve months of high-intensity weightlifting reduces mortality, nursing home admissions, and inability to execute daily living activities in patients with hip fractures. A review of 13 RCTs on progressive resistance training in nursing homes finds significant improvements in strength and functional performance, even among the very old, very sedentary, and institutionalized subjects.
So clearly lifting weights/resistance training has a lot of health benefits for aging people, those with various age-related diseases, and works for those who want to improve their body composition. But what about benefits for younger people, or those without any specific issue/disease/dysfunction they want to improve?
Lifting weights for just 3-4x/week, over 8 weeks, for 20 minutes at a time, improved self-concept in depressed young women lasting for at least 12 months after the lifting regimen. Seriously, 2 months of light lifting (the researchers actually prevented them from getting their heart rate up too high) for a year of mental health benefits? Another study assents in improved self-concept and self-satisfaction in women after 12 weeks of progressive resistance training. An excellent, lengthy review of benefits to the mental health of strength training in adults finds that the evidence supports the conclusions that strength training is associated with a reduction in anxiety, low back pain, osteoarthritis, improvements in cognition in older adults, improvements in depression, and reduction in fatigue symptoms, as well as improved self-esteem and energy. The review has over 200 citations and is great reading if you're interested in this topic. A review finds positive anxiolytic effects of resistance training at low to moderate intensity, in both single bout and long term training.
A study on Spanish children and adolescents finds an association between muscular fitness and psychological positive health, and reduce risky behaviors like drinking and smoking. A review of meta-analyses finds that resistance training is probably as good as, possibly better than, aerobic exercise in treating anxiety and depression disorders. (Meta-analysis of anti-depressant effects of exercise finds that effects increase after accounting for publication bias!) Vigorous physical activity associated with reduced stress, pain, sleep complaints, and depressive symptoms in young adults, beyond moderate physical activity (they had more total sleep time and more REM time, as well as a lower percentage of light sleep).
An RCT on older depressed adults found that high-intensity progressive resistance training 3x/week (~80% 1RM training loads increasing each week to maintain exertion levels) worked significantly better than low intensity (~20% 1RM loads) 3x/week OR standard general practitioner care to reduce depression. Strength gain was associated with reduced depression at r=0.4, p<0.004! Perceived quality of life and sleep quality also improved more in the high-intensity group than the others.
A study on 43 male law enforcement officers who were not previously exercising found that circuit weight training for 4 months significantly improved their mood, improved job satisfaction, and reduced anxiety, depression, and hostility.
How about memory? One study finds that strength training in elderly adults with memory impairment significantly improved their memory, though it didn't improve their scores on the WAIS. Another study, again on the elderly, found that a 1x/week for 8 weeks lifting program significantly improved memory, lasting at least a year after the training (also strength gains were significant and lasted a year after as well, even after controlling for any increased activity levels after the training program!) Another study on women 65-75 compared 1x and 2x/week resistance training found no significant improvement in memory, but it did find an improvement in executive cognitive functioning (as measured by the Stroop test) with no significant difference in benefit between the 1x vs. 2x/week groups, though both of these groups did significantly better than a group that did "balance and toning" exercises (all bodyweight, stretching, tai chi, etc.) which controlled for the effects of regular social interaction/traveling to a fitness center class. The 2x/week group was the only group to see an improvement in peak muscle power at the end of the study.
A double-blind, double-sham controlled RCT studied resistance training and cognitive training effects on cognitive function in older adults with mild cognitive impairment. Resistance training significantly improved cognitive and executive function (as measured by WAIS Matrices), though cognitive training did not. The evidence for an effect on memory seemed to be minimal and mixed at best.
Muscular fitness is associated with reduced adiposity, improved metabolic control, and reduced insulin resistance, each of which is associated with working memory. The actual study itself supports this conclusion in 9 to 11-year-old schoolchildren.
A 2017 review of 36 RCTs on exercise interventions for cognitive function in adults 50+ suggests that resistance training has significant positive effects on executive function, memory, and working memory, regardless of baseline cognitive status. The difference between aerobic and resistance training was not significant, but multicomponent training (including both) seemed to work slightly better than either alone. Tai Chi appears to be even better than any of them though, surprisingly (Table 1). Yoga was the only exercise type to not produce a significant positive effect estimate.
Strength and Mortality: Get Jacked, Live Forever
So far, the evidence seems to show benefits from both cardio/aerobic training and from lifting weights (which can also be aerobic, depending on your routine). Why should you lift weights specifically? Why not just stick to the low-intensity steady state (LISS) cardio? Well, for one, you won't get jacked running unless you're doing sprints, and for two, there are tons of benefits associated with strength itself.
Muscular strength is inversely and independently associated with all-cause mortality and cancer in men, (more recent systematic review agrees)even after adjusting for cardiorespiratory fitness, age, physical activity, smoking, alcohol intake, BMI, medical conditions, and family history of CV disease. Muscular strength is inversely associated with mortality in hypertensive men. Muscular strength is inversely associated with metabolic syndrome incidence in men. Muscular strength is associated with a reduced risk of premature death (before 55 years), including from suicide, in Swedish male adolescents. Muscular strength associated with higher body satisfaction and confidence, and reduced neuroticism in college-age males. Muscular strength is inversely related to the incidence/prevalence of obesity in adult men. A study of over a million Swedish men finds that all strength indicators (knee extension strength, grip strength, etc.) are inversely associated with disease risk, including coronary heart disease and strokes, plus vascular disease risk and arrhythmia incidence. Lower extremity muscular strength associated with leukocyte telomere length, meaning stronger people exhibited less shortening of telomeres, an important part of the aging process. Muscular fitness in children and adolescents inversely associated with adiposity, cardiovascular disease, and metabolic risk factors, and positively associated with bone health, self-esteem, and "perceived sports confidence".
Grip strength found to be an accurate predictor of all causes of mortality in middle-aged and elderly persons (both sexes!) in Japan. Midlife hand grip strength highly predictive of functional limitations and disability 25 years later in men in Hawaii. Handgrip strength predicts all-cause mortality in women from the Leiden 85-plus study. Grip strength inversely associated with all-cause mortality, heart attacks, and strokes. Grip strength inversely associated with mortality in adults 50+. Systematic review finds 17/22 grip strength x mortality studies found a significant negative association, with a 0.96 hazard ratio for every 1kg increase in continuous handgrip strength (the same review says higher grip strength is a protective factor for developing Alzheimer's and dementia, as well as mobility problems). A 2018 study of over 100,000 participants in the UK from 2005-2010 finds significant positive associations (p<0.001) between higher handgrip strength and better performance on five cognitive tasks (visual memory, number memory, prospective memory, reasoning, and reaction time) in both majorly depressed subjects and a similar result in healthy controls, and all except number memory in subjects with bipolar disorder.
A 2018 study on multi-ethnic older women in the US finds that grip strength and 5x chair rise time are inversely associated with reduced all-cause mortality, even after controlling for moderate-to-vigorous physical activity (measured with digital devices) and gait speed (which correlates with cardiorespiratory fitness). However, a 2018 systematic review suggests that higher handgrip and knee extension strength is not statistically associated with reduced cancer mortality specifically. Why is grip strength so well associated with all-cause mortality? I don't know, and neither do the scientists, apparently.
If you're a high level mid or long-distance runner, strength training improves your running economy, according to a systematic review of 5 RCTs.
- A review of 23 studies finds a consistent inverse association between muscular strength and all-cause mortality, even after adjusting for confounders (including 1 study accounting for cardiorespiratory fitness). A different review finds inverse association with obesity, risk of hypertension, and incidence of metabolic syndrome, though many studies found no difference after accounting for cardiorespiratory fitness, and the evidence is noted as "weak" in the conclusion (so you still have to work out somehow for the benefits)
- Gait speed and 5x chair rise time also both inversely associated with all-cause mortality
- Muscular strength associated with improved mental wellbeing, reduced fall risk, and improved bone health (when resistance training is combined with high impact training like running or plyometric work)
- The recommendation quoted directly: Based on the review level evidence reported in this study middle-aged and older adults should: Undertake a program of exercise at least twice per week that includes high-intensity resistance training, some impact exercise (running, jumping, skipping, etc.) and balance training. The specific exercises included and the volume of exercise per session should be tailored to individual fitness and physical capabilities.
Resistance training is associated with improvements in: bone mineral density, intra-abdominal fat, muscular strength, body composition, insulin resistance, lower back pain, blood pressure, general cognition, depression, anxiety, fatigue, self-esteem, sleep quality, mood, memory in older adults, osteoarthritis pain, all-cause mortality, cardiovascular disease, general functional performance, and various symptoms of Type 2 diabetes, Parkinson's disease, and MS.
Muscular strength is inversely associated with: all-cause mortality (and premature death), cancer, cardiovascular disease, stroke, obesity, metabolic syndrome, hypertension.
Grip strength is inversely associated with: all-cause mortality, heart attack, stroke, functional limitations, and disability later in life.
Grip strength is associated with: performance in various cognitive tasks among majorly depressed (p<0.001) and healthy controls.
Injuries per 1,000 Training Hours
What are the risks of lifting weights/resistance training? They mostly consist of minor sprains or strains and various joint and ligament/tendon injuries, though in extreme cases muscles can be torn and bones were broken (it's not easy for a newbie to do this, though). A study on prepubescent males found strength training to be quite safe. An (informal) review of studies on injuries in strength athletes found injuries per 1,000 training hours to be similar or lower in most strength sports, especially bodybuilding, than running or doing triathlons. Another review supports the same conclusion.
Even the risks to pregnant women are minimal.
Anecdotally, I see more injuries in minimally competitive college intramural sports than I do in the gym, and over about 5 years of on and off lifting, I've only really injured myself two or three times, always when slacking on my form.
There are multiple excellent resources that compile information on strength, resistance training, lifting and programming variables, and nutrition. In the above review, I have linked Strength and Conditioning Research and Bayesian Bodybuilding/Menno Henselmann (another example article: a review of research indicates no benefit of protein intake beyond about 0.8g/lb/day, even when cutting. I also like Stronger by Science and Examine.com which is outstanding for nutrition and supplement research summaries.
The r/bodybuilding wiki can be found here, it is packed with info on the sport of bodybuilding. Their linked program picker will give you some ideas of routines for different goals. If you're a beginner, my recommendations would be Starting Strength (SS) modified with some bodybuilding accessories, Stronglifts 5x5 (SL) also modified, or Greyskull LP (linear progression). If you've lifted before but got out of it or don't know where to go next, try 5/3/1, Madcow, Doggcrapp, or the Texas Method. Renaissance Periodization has an excellent guide to exercises and hypertrophy for every body part, including videos of proper form and a description of how much volume (sets and reps) to do. There's a lot of nuances about which particular lifts to do, lots of different opinions, and some lifts are more or less risky than others, or more commonly result in problems (e.g. upright rows are often found to be uncomfortable or injurious, more so than the similar high pulls or shrugs). Ideally, you should do exercises you enjoy, that help you achieve your goals (specificity), and preferably more efficient exercises.
Never lift heavy without getting the form down first. Get a coach, take a video, ask someone else, get feedback. You should feel confident and at ease in every lift before even trying to go heavy.