Category: Myth-busters

In short: You do not need 10,000 steps a day for your health to benefit. The number began as the name of a Japanese pedometer in 1965, not as a research finding. Large studies now link the biggest drop in risk of early death to the range from very few steps up to about 7,000 to 8,000 a day, with benefits leveling off around 6,000 to 8,000 for adults over 60 and 8,000 to 10,000 for younger adults. For weight loss, steps help most as part of a plan with eating changes.

Fitness trackers often set 10,000 steps as the default goal, and many people feel they have failed if they fall short. This article explains where the number came from, what the biggest step studies found, and how steps fit into weight loss. For a practical walking plan, see our guide to walking for weight loss, which has a 6-week plan and pace targets.

Where 10,000 steps came from

The goal traces back to Japan in the 1960s. In 1965, a company sold a pedometer called the manpo-kei, which translates as “10,000 steps meter”. Dr. I-Min Lee, a Harvard epidemiologist who has studied step counts and health, told Harvard Health Publishing that “the name was a marketing tool”. A 2004 review by step researchers traced the figure to Japanese walking clubs and a business slogan, and said that 10,000 steps was a reasonable estimate of daily activity for healthy adults but might not be sustainable for some groups, including older adults and people with chronic conditions.

In other words, 10,000 was a round, memorable number that happened to sit near what active people do. It was never tested as a threshold, and for decades nobody checked whether fewer steps would bring most of the benefit. Our history of exercise fads shows how often fitness targets begin as marketing.

What the big step studies found

Researchers finally tested the question with step counters worn by tens of thousands of people, then followed them for years. Three studies stand out.

Older women (2019). In the Women’s Health Study, 16,741 women with an average age of 72 wore a step counter for a week and were followed for about four years. Women in the lowest group averaged 2,718 steps a day. Those averaging 4,363 steps had a 41% lower risk of dying during the study, and the risk kept falling up to about 7,500 steps a day, then leveled off. How fast they walked mattered less once the total number of steps was taken into account.

US adults (2020). In a national sample of 4,840 adults aged 40 and older, followed for about 10 years, taking 8,000 steps a day was linked to a 51% lower risk of death from any cause than taking 4,000, and 12,000 steps to a 65% lower risk, after adjusting for age, health conditions, body mass index and other factors.

Fifteen studies pooled (2022). The largest analysis combined data from 15 studies and 47,471 adults, followed for a median of 7.1 years. Compared with the least active quarter, who averaged 3,553 steps a day, people averaging 5,801 steps had a 40% lower risk of death, 7,842 steps a 45% lower risk, and 10,901 steps a 53% lower risk. The curve flattened: for adults 60 and older, risk stopped falling much beyond 6,000 to 8,000 steps a day; for younger adults, beyond 8,000 to 10,000.

The biggest gain comes from moving out of the least active group. Going from about 3,500 to about 5,800 steps was linked to a 40% lower risk; the extra 5,000 steps after that added only about 13 more points. If you are taking very few steps now, a modest increase is where most of the benefit appears.

The 2025 update: about 7,000 steps for many health outcomes

A 2025 review in The Lancet Public Health looked beyond death to other health outcomes, using 57 studies from 35 groups of people. Compared with 2,000 steps a day, about 7,000 steps a day was linked to a 47% lower risk of death from any cause, a 25% lower risk of heart disease, a 37% lower risk of dying from cancer and a 14% lower risk of type 2 diabetes. For death, heart disease, dementia and falls, the benefit curve bent at around 5,000 to 7,000 steps, meaning each extra thousand steps added less after that point.

It also helps to know what these studies counted. Participants wore a research-grade step counter during waking hours for about a week; in the US study, people wore it for an average of 5.7 days and 14.4 hours a day. Every step counted, from walking to the bus to housework, not only planned walks. So the totals are comparable to an all-day count on your phone or tracker, though readings can vary from one device to another. A single week was used to describe each person’s habits for years afterward, which is another reason to treat the exact thresholds as approximate.

One important caution applies to all of these numbers. They come from observational studies: people who walk more may differ in many ways, such as being healthier to begin with. The researchers adjust for what they can, but these studies show strong links, not proof that each extra step causes the benefit. Our guide on how to read a weight-loss study headline explains the difference.

Steps and weight loss

Steps on their own move the scale only a little. In a meta-analysis of nine pedometer-based walking programs without any diet change, 307 participants lost 1.27 kg (about 2.8 lb) on average over a median of 16 weeks, or about 0.05 kg a week; longer programs led to more loss. That is modest, but it adds up and comes with the health benefits above. Programs like these typically raise daily steps by about 2,000 to 2,500.

The American College of Sports Medicine has found that 150 to 250 minutes a week of moderate activity brings modest weight loss, and that larger amounts, or activity combined with eating changes, do more. Walking is also one of the best tools for keeping weight off once you have lost it; our guide to maintaining weight loss explains why. For the weight-loss side, pair your steps with a steady calorie deficit and some strength training to protect muscle. You can see what a walk burns at your weight with our calories burned calculator.

Steps or minutes: how they line up with the guidelines

The Physical Activity Guidelines for Americans are written in minutes, not steps: 150 to 300 minutes a week of moderate activity, such as brisk walking, plus muscle-strengthening activity on two or more days. Step researchers have found that about 100 steps a minute is a common marker of moderate-intensity walking for adults. So 30 minutes of brisk walking adds roughly 3,000 steps on top of the steps you take in daily life, by that cadence.

Pace is a bonus rather than a requirement. In the 2022 pooled study, the link between faster stepping and lower risk weakened once total steps were counted, although the fastest 30 minutes of the day still mattered somewhat. Walking faster does burn more per minute, as our walking vs running comparison shows, and it can help you fit your minutes into a shorter time.

Is 10,000 steps a bad goal, then?

Not at all. It is just not the minimum. The same 2004 review that traced the number to Japan proposed rough bands that are still useful: under 5,000 steps a day as a “sedentary” marker, 5,000 to 7,499 as typical daily activity without exercise, 7,500 to 9,999 as “somewhat active”, and 10,000 or more as “active”. A 2011 update found that healthy adults take anywhere from about 4,000 to 18,000 steps a day. If you already reach 10,000 and enjoy it, there is no reason to cut back; for adults under 60, the 2022 pooled study saw benefit continue up to about that level.

The problem with 10,000 is what it does to people far below it. If your average is 3,000 steps, a goal of 10,000 can feel impossible and lead you to give up, even though the research suggests that reaching 5,000 or 6,000 would already be linked to a large drop in risk. The 2004 reviewers made the same point: goals based on gradual increases from your own baseline were showing promise and are easier to sustain.

Age matters as well. In the study of older women, the benefit leveled off at about 7,500 steps a day, and in the 2022 analysis the plateau for adults 60 and older came at 6,000 to 8,000. For many older adults, a realistic target in that range, plus balance and strength exercises, is a better fit than chasing a five-figure number.

How to pick a step goal that works for you

There is no single number for everyone. A useful starting point is your own average: check what your phone or tracker shows for the last week, then add a little.

Small changes count: a walk after dinner, a phone call on the move, or an indoor walking pad on bad-weather days. Our guide to walking pads and our picks of fitness trackers and walking and step-counter apps can help if you want tools, though none is required. Step counts from wrist devices are estimates, and our fitness tracker vs smart ring comparison explains how accurate they tend to be. If steps are hard because of joint pain, our list of low-impact workouts has options that count toward the same weekly minutes.

Steps are one measure among many. Our guide to tracking progress without the scale covers others, and our check of viral workout trends looks at Japanese walking and other walking-based fads. If you have a health condition that limits walking, ask your clinician what amount is right for you.

In short: Not much, on their own. Adults do have some brown fat, and cold switches it on, but careful measurements found it burns only about 15 to 25 extra calories a day in mild cold, less than a 10-minute brisk walk. Very cold water raises your calorie burn for as long as you shiver, yet no trial has shown that cold plunges lead to meaningful weight loss. The weight you lose in a sauna is sweat, and it comes back when you drink. Both can be pleasant habits, but they are not weight-loss tools.

Cold plunges, ice baths and “cold therapy” are everywhere on social media, often with the promise that they turn on fat-burning brown fat and fire up your metabolism. Saunas come with their own claims about sweating off pounds. This article checks those claims against human studies. For the bigger picture of how your body uses energy, see our guide to metabolism and weight; for foods sold as metabolism boosters, see metabolism-boosting foods: fact or fiction.

What brown fat is, and how much of it adults have

Most body fat is white fat, which stores energy. Brown fat is different: it is packed with mitochondria and a protein called UCP1 that lets it turn energy straight into heat. Babies and small mammals depend on it to stay warm. Until 2009, most scientists thought adults had almost none. That year, studies in the New England Journal of Medicine showed that many adults do have active brown fat, mainly in a region from the front of the neck down into the chest.

How much depends on who you are and how cold it is. On PET-CT scans done for other medical reasons in nearly 2,000 people, clear brown-fat deposits showed up in 7.5% of women and 3.1% of men; they were less common in older people, in people taking beta-blockers and when the weather was warm. When researchers deliberately cooled 24 young men to 16°C (61°F), brown-fat activity appeared in 23 of them, but it was lower in men with overweight or obesity than in lean men. So brown fat is real and cold does activate it. The question is how much energy it actually uses.

How many calories does brown fat burn?

Much less than the headlines suggest. A 2013 study measured oxygen use directly inside brown fat with PET scans in 25 adults at rest and in mild cold (15.5°C, about 60°F). In the people with the most brown fat, about 59 grams on average, it added roughly 3 calories a day at rest and about 6 calories a day in the cold, by direct measurement. The authors concluded that cold-activated brown fat accounts for about 15 to 25 calories a day even in people with relatively large deposits, and called it “a minor source” of heat production in humans. Most of the extra energy you spend in the cold comes from muscles, through shivering and tensing.

Our calories burned calculator uses the same Compendium values, so you can check the walking numbers for your own weight and pace. For why a short walk adds up over time, see our guide to walking for weight loss.

Can you grow more brown fat with regular cold?

Somewhat, in the lab. In a Dutch study, 10 days of mild cold acclimation raised brown-fat activity and non-shivering heat production in volunteers, and people reported feeling more comfortable in the cold and shivering less. In a Japanese randomized study, 12 young adults with little brown fat spent 2 hours a day at 17°C (63°F) for six weeks, while 10 others kept to their normal routine. The cold group’s brown fat became more active and their body fat fell by about 0.7 kg (1.5 lb), or 5.2% of their fat mass; the control group’s did not change. Their body weight, however, did not change significantly.

Those are encouraging signals for research, and they come with big caveats: very small groups, two hours of cold every day (about 84 hours in total) and no change on the scale. In another small study, 10 days at 14-15°C (57-59°F) improved insulin sensitivity by about 43% in eight people with type 2 diabetes, but brown fat itself changed only a little; most of the effect was in muscle. None of these studies tested cold plunges, and none showed weight loss you would notice. Our guide to how to read a weight-loss study headline explains why small, short studies like these are a starting point, not an answer.

Cooler rooms, cold showers and “brown fat” supplements

What about everyday cold, such as a cooler bedroom or a cold shower? The Dutch researchers who ran the 10-day acclimation study suggested that a home or office temperature that varies, with frequent mild cold, might be an acceptable way to raise energy use a little. That is an idea for further research, not a tested weight-loss method, and the amounts involved are small. Comfort and sleep matter too; if a cold room keeps you awake, the trade-off is not worth it.

The same Japanese team also tested capsinoids, mild relatives of the compound that makes chili peppers hot. Six weeks of daily capsinoids raised cold-induced energy use in a small group of volunteers, but the study did not report weight loss from them. Supplements sold to “activate brown fat” rely on this kind of early evidence. Our article on metabolism-boosting foods shows how small the effects of chili, caffeine and green tea are in practice, and our guide to fat burners explains why the label claims run far ahead of the research.

The pattern is the same each time. Brown fat is a fascinating area of research, and scientists hope it could one day lead to treatments, but nothing you can do at home has been shown to turn it into a meaningful weight-loss engine. The big levers are still what you eat and how much you move.

Cold plunges and ice baths

Cold water pulls heat from the body much faster than cold air, so your body works hard to stay warm. In a classic study, young men sat in water up to the neck for one hour. At 32°C (90°F), their metabolic rate did not change. At 20°C (68°F), it rose by 93%. At 14°C (57°F), it rose by 350%, along with large jumps in noradrenaline, heart rate and blood pressure. That is a real increase in calorie burn, but it lasts only while you are cold, it comes mostly from shivering, and an hour at that temperature is far beyond a typical 2- to 5-minute plunge.

We found no randomized trial showing that regular cold plunges or cold-water swimming cause meaningful weight loss. A 2022 review of 104 studies on voluntary cold-water immersion found signs that it may change body fat and improve insulin sensitivity, but said clear conclusions were hampered because most studies were small, often in one sex, and used different temperatures; the authors called the topic “a continuing subject of debate”. A 2023 randomized cross-over trial in 18 rugby players found no effect of regular cold or hot water immersion after weight training on body composition. Winter swimmers may also simply be healthier people to begin with.

Many people enjoy cold plunges for how they feel afterward, and athletes use them for recovery; those are separate questions from weight. Our check of viral workout trends covers other social-media favorites with the same evidence lens.

Saunas: what the scale shows is water

A sauna makes you sweat, and sweat weighs something. In a study of 674 university students, two 10-minute sessions in a 90°C (194°F) dry sauna reduced body weight by 0.37 kg (about 0.8 lb) in women and 0.50 kg (about 1.1 lb) in men on average; people with a higher BMI lost more. That weight is water, and it returns as soon as you rehydrate. The researchers’ practical advice was about the opposite of weight loss: people with a higher BMI should take particular care to replace fluids.

Sweating does not “detox” fat either; the kidneys and liver handle waste, as our article on detox teas and cleanses explains. And sauna suits, which make you sweat during exercise, have a long history as a weight-loss gimmick, covered in our history of weight-loss hoaxes.

Saunas may still be good for you in other ways. In a Finnish study that followed 2,315 middle-aged men for about 20 years, those who used a sauna 4 to 7 times a week had a lower risk of sudden cardiac death than those who went once a week, after adjusting for other risk factors. That is an observational link in a population where sauna is a lifelong habit, not proof that saunas cause the benefit, and it says nothing about weight. A review of sauna research found it well tolerated by healthy people and by people with stable, treated heart conditions, with one caution: blood pressure medicines can make you light-headed when you stand up afterward.

What does move the needle

The approaches with strong evidence are less exotic: a steady calorie deficit, regular activity you enjoy, strength training to protect muscle, enough sleep and, for some people, medical treatment. If you like cold plunges or saunas, there is no need to stop; just do not count them as your weight-loss plan. Our list of weight-loss myths science has busted and our guide to keeping weight off are good next reads.

In short: Mostly no. When researchers train one body part and measure the fat over it, the fat usually does not shrink faster there than anywhere else: a 2022 pooled analysis of 13 studies and 1,158 people found no spot-reduction effect at all. Exercise still matters a lot, because it helps you lose fat from the whole body, including the belly, and it builds the muscle underneath. One small 2023 trial hinted at a local effect, so the door is not fully closed, but the practical advice has not changed.

If your real question is how to slim your middle, our practical guide on how to lose belly fat covers that step by step. This page answers a narrower question: can crunches, inner-thigh squeezes or arm toning burn the fat in that exact spot? Below we walk through the studies, explain why the idea refuses to die, and show what does change your shape.

Where the idea comes from

Spot reduction feels logical. When you do a lot of sit-ups, your stomach muscles get tired and warm, so it seems natural that they would use the fat right on top of them. Fitness marketing has leaned on that intuition for decades, with ab rollers, belly belts and “trouble zone” workouts. The authors of the 2022 review we describe below put the long life of the belief down to “wishful thinking and convenient marketing strategies”.

The body works differently. Fat is stored in fat cells all over the body, and when you burn more energy than you eat, hormones release fatty acids from fat stores into the blood, where any working muscle can use them. Which stores give up their fat is not simply decided by which muscle is moving. That is why the studies below compare a trained area with an untrained one in the same person: if spot reduction worked, the trained side should lose more.

What the studies found

Six weeks of ab exercises (2011). In a randomized trial at Brigham Young University, 24 sedentary adults were split into a control group and a group that did seven abdominal exercises, two sets of 10 repetitions, five days a week for six weeks, while everyone kept their usual calorie intake. The ab group got much stronger: they managed 47 curl-ups on average at the end, compared with 32 in the control group. But there was no significant change in body weight, body fat percentage, belly fat measured by scan, waist circumference or skinfolds.

Twelve weeks of training one arm (2007). A larger study had 104 men and women train only their non-dominant arm for 12 weeks. MRI, which measures fat along the whole upper arm, found the same fat change in the trained and untrained arms. Skinfold calipers suggested a small local loss in men only. The authors concluded that the MRI results support “the notion that spot reduction does not occur”.

Twelve weeks of training one leg (2013). In a Chilean study, 11 young adults did very long, light leg-press sets (960 to 1,200 repetitions per session) with one leg only, three times a week. Total body fat fell by 5.1%. But the fat did not come off the trained leg: it came off the arms and the trunk instead.

The pooled evidence (2022). The same research group then gathered every suitable study that trained one limb and compared it with the other. Thirteen studies with 1,158 people aged 14 to 71 made the cut, giving 37 comparisons. Seventeen of them favored the trained limb and 20 favored the untrained one, which is about what you would expect from chance. The pooled effect was essentially zero, the studies agreed with each other, and there was no sign that missing studies skewed the result. Their conclusion: localized muscle training “had no effect on localized adipose tissue depots”.

The study that says “maybe”

To be fair to the other side: a 2023 randomized trial from Norway reported a local effect. Sixteen men with overweight either ran on a treadmill for 45 minutes, or ran for 27 minutes and then did torso rotations and crunches for the rest of the session, four days a week for 10 weeks, with energy use matched between groups. The ab group lost about 1.2 kg (7%) of trunk fat, while the running-only group showed no change in trunk fat. Total fat loss was similar in both groups (about 1.7 kg vs 1.1 kg), and the running group actually lost more body weight (2.3 kg vs 1.2 kg).

This is interesting, but it is one small trial in middle-aged men, and the ab work was long and continuous, closer to an endurance workout than a few sets of crunches. Until it is repeated in larger and more varied groups, it does not outweigh a meta-analysis of 13 studies. The fair summary is that any local effect, if it exists, is small, and it does not happen without overall fat loss.

So why do some people see a change in one spot?

Plenty of people swear that ab work flattened their stomach. Usually, several real things are happening at once:

• Overall fat loss. People who start an ab routine often change their eating and activity too. The belly shrinks because body fat fell everywhere.
• Stronger, firmer muscle. Trained muscles look and feel firmer, and stronger core muscles can change how you stand. That can change the outline without any fat loss.
• Less bloating. A flatter stomach in the morning often has more to do with gas and digestion than fat. Our guide to a flatter stomach covers the four things that change how a belly looks.
• Different photos. Light, posture and arm position change how a waist looks on camera. Our before-and-after photo explainer shows how.

What does reduce belly fat

The fat inside the belly, around the organs, is called visceral fat, and it is the kind most linked with heart disease and type 2 diabetes (our visceral fat guide explains why). The good news is that it responds well to whole-body exercise. A 2012 meta-analysis of 35 trials that measured visceral fat with CT or MRI found that aerobic exercise reduced it compared with no exercise, while resistance training alone did not show a significant effect. A 2013 review of 15 studies with 852 people found that exercise lowered visceral fat even without a calorie-cutting diet.

So the most reliable recipe for a smaller waist is not a special ab move. It is the combination that reduces body fat overall:

• A modest calorie deficit from an eating pattern you can keep. Our calorie deficit guide and calorie calculator help you estimate it.
• Regular aerobic activity, such as brisk walking. The Physical Activity Guidelines suggest 150 to 300 minutes of moderate activity a week.
• Strength training for the whole body on two or more days a week. It protects muscle while you lose weight: a 2021 overview of reviews found resistance training reduced lean-mass loss during weight loss by about 0.8 kg. See our strength training guide.
• Core work for strength, posture and comfort, not as a fat burner. Planks, carries and bird-dogs are worth doing for a strong back and middle.

Arms, thighs and the “stubborn” areas

The same rule applies to upper arms, inner thighs, hips and the bra-line. Training those muscles makes them stronger and firmer, which many people love, but the fat over them goes down when your overall body fat goes down. If one area seems slow to change, that is common and not a sign of failure. Keep going with the whole-body plan and measure progress in several ways; our list of ways to track progress without the scale can help on the weeks when the mirror does not seem to move.

What about fat freezing and other “spot” treatments?

Procedures such as cryolipolysis (fat freezing) and liposuction do remove fat from a chosen area. That is the one place where “spot reduction” is real, but it is cosmetic body contouring, not weight loss, and it does not replace the habits above. Our body contouring hub and non-surgical fat reduction compared explain the options, costs and limits. If weight loss is the goal, start at our lose weight hub.

The verdict

Spot reduction is mostly a myth. Decades of studies, pooled in 2022, show that training a body part does not burn the fat over it in any meaningful way, and the one recent trial that disagreed is small. That is not a reason to skip crunches or arm work: strong muscles help you move, protect your back and change your shape as body fat comes down. Just pair them with whole-body activity and a sustainable eating plan, and judge progress over weeks, not days. For more claims checked against the research, see our weight-loss myths roundup.