Key points
- Cardio on its own usually brings modest weight loss. In trials where people kept eating as usual, average losses ranged from under 1 kg to about 5 kg over eight to ten months, and only large amounts of exercise reached the top of that range.
- It still matters a great deal. Cardio lowers blood pressure and blood sugar, shrinks the deep fat around your organs and is one of the habits most linked to keeping lost weight off.
- Food and movement work best together. Good food drives most of the drop on the scale; cardio adds to it and protects your health along the way.
- LISS and HIIT give similar fat loss. Steady, moderate cardio and interval training reduce body fat by about the same amount, so choose the one you enjoy and can keep up.
- Cardio and weights are a team, not rivals. Cardio uses more energy, strength work protects muscle, and the combination gives the best overall result. The order within a session matters little for weight loss.
- Talk to your doctor first if you have heart or lung disease, diabetes treated with insulin or similar medicines, high blood pressure or joint problems, and before trying hard intervals.
What counts as cardio?
Cardio is any movement that uses your large muscles in a steady rhythm and keeps your heart and breathing raised for a while. Walking briskly, cycling, swimming, water aerobics, dancing, rowing and using an elliptical trainer all count.
Scientists usually call it aerobic or endurance exercise. In everyday gym talk you will also meet two shorter labels, which come up again further down this page.
- LISS stands for low-intensity steady state: the same comfortable pace for the whole session, like a 40-minute walk or an easy bike ride.
- HIIT stands for high-intensity interval training: short bursts of hard effort, each followed by a slower recovery period, repeated several times.
Cardio is not the same as impact. Swimming and cycling are hard on your heart and easy on your joints. Running and jumping are the opposite on both counts. That distinction matters a lot when you live in a heavier body, and we use it to rank the options later on.
Slow, stretch-based classes such as gentle yoga or mat pilates build strength and flexibility, but they rarely raise your breathing enough to count as cardio. Our page on yoga and pilates for weight loss explains where they fit in a week.
How much weight can cardio alone help you lose?
On its own, without changes to what you eat, cardio usually leads to a few kilos of weight loss over many months, and sometimes less. That is the honest answer from the best long trials, and it is better to hear it now than to feel let down in week six.
Three pieces of research show the range well. They studied adults with overweight or obesity who were asked to keep eating as usual, so any change came from the exercise itself.
| Study | Who took part | Exercise | Average result |
|---|---|---|---|
| Midwest Exercise Trial 2 | 141 inactive young adults with overweight or obesity | Supervised cardio 5 days a week for 10 months, burning about 400 or 600 kcal per session | About 3.9 kg (4.3 %) and 5.2 kg (5.7 %) lost; the control group gained 0.5 kg |
| STRRIDE | 182 inactive adults aged 40 to 65 with overweight | 8 months of walking or jogging in three different programmes (two weekly amounts, two intensities) | The largest amount (similar to jogging about 32 km a week): 2.9 kg lost. Smaller amounts: under 1 kg. Controls gained 1 kg |
| Cochrane review | 43 trials, 3,476 adults with overweight or obesity | Many types and amounts of exercise | Small weight loss with exercise alone; adding exercise to a diet gave about 1.1 kg more than the diet by itself |
The Midwest trial is the most encouraging, but look at the conditions. Every session was supervised, participants were young, and only people who completed at least 90 % of their sessions were counted. Most of us do not live like that.
A large overview of exercise research, covering 12 reviews and 149 studies, puts the typical figure for exercise programmes at roughly 1.5 to 3.5 kg. It also found something easy to miss: exercise reduced fat mass, by about 1.3 to 2.6 kg, and the fat stored deep inside the belly, which matters for health even when the scale barely moves.
So cardio is not a weight loss method on its own for most people. It is a powerful partner to good food, and a health treatment in its own right. Our guide on how to lose weight shows how all the parts fit together.
Why cardio loses less weight than the calculator predicts
Your body partly makes up for the energy you burn, mostly by nudging your appetite upwards. This is called compensation, and it is normal biology, not a lack of discipline.
The E-MECHANIC trial measured it carefully. For 24 weeks, 198 adults with overweight or obesity did supervised cardio in two different doses, while researchers tracked their energy intake with precise lab methods.
Both exercise groups ended up with less weight loss than their burned calories predicted: about 1.5 kg less in the lower-dose group and 2.7 kg less in the higher-dose group. The main reason was that they ate roughly 90 to 125 kcal a day more, together with a rise in appetite. Their metabolism and their activity outside the gym did not explain the gap.
Interestingly, people who compensated most were more likely to believe that a workout cancels out less healthy food. That belief is common and understandable. It is also the reason we suggest not treating exercise calories as food you have earned.
What helps in practice
- Plan a filling snack or meal with protein and fibre after a longer session, so a big hunger does not catch you off guard.
- Drink water rather than sports drinks; for ordinary cardio sessions, plain water is enough.
- Use the calories burned calculator out of curiosity, but steer your eating by hunger, fullness and a steady plan, not by the number on a machine.
Is the afterburn effect real?
Yes, but it is small. After exercise your body keeps using a little extra oxygen and energy while it recovers, which scientists call EPOC (excess post-exercise oxygen consumption).
A review of the research found that this extra energy adds up to only about 6 to 15 % of what the workout itself used, and the longer-lasting versions need very hard or very long sessions. The authors concluded that early hopes for afterburn as a weight loss tool were largely unfounded. What counts is the energy you use while you are moving.
Does cardio burn fat?
Yes. Regular cardio reduces body fat, and it is especially good at shrinking visceral fat, the deep fat around your liver and other organs that is most closely linked to type 2 diabetes and heart disease.
A meta-analysis of 35 trials that measured belly fat with CT or MRI scans found that aerobic exercise clearly reduced visceral fat compared with no exercise. Resistance training on its own did not show a clear effect in that analysis. The authors also noted that cardio below the usual weekly targets for weight loss still seemed enough to make a difference here.
This explains a frustrating pattern. In the STRRIDE trial, even the groups that lost less than a kilo got smaller around the waist and hips. Your clothes and your tape measure can change while your scale barely moves. Our page on belly fat explains why the deep fat matters and how to measure your waist.
Do you need to stay in the fat-burning zone?
No. Gentle cardio uses a higher share of fat as fuel during the session, but your body fat over weeks depends on your total energy balance, not on the fuel mix of one workout. The details, and target heart rates for your age, are on our heart rate zones calculator page.
Cardio also cannot pick where you lose fat. Cycling does not slim your thighs first, and no machine targets the belly. Your body decides the order.
Why cardio still matters if the scale moves slowly
Cardio protects your heart, blood vessels and metabolism whether or not you lose weight, and it is one of the strongest habits among people who keep weight off. Those are reasons enough to keep going.
The Cochrane review found that exercise alone lowered diastolic blood pressure, triglycerides (a blood fat) and fasting blood sugar, even in trials where weight loss was small. Its authors concluded that exercise improves heart and circulation risk factors even when no weight is lost.
Keeping lost weight off
The American College of Sports Medicine reviewed the evidence on activity and body weight. It found that people who keep weight off after losing it tend to be more active, often above 250 minutes a week, although this comes from observational studies rather than strong trials.
That uncertainty is worth stating plainly. A later overview found no clear effect of exercise programmes on weight maintenance in the few trials available. Still, almost every long-term plan that works includes regular movement, and our page on why weight often comes back explains the biology behind regain.
Feeling better, often first
Many people notice changes long before any weight loss: climbing stairs without stopping, sleeping more deeply, a calmer mood and more energy in the afternoon. These gains are real results, and they make the next session easier to start.
How much cardio for weight loss?
For health, adults are advised to do 150 to 300 minutes of moderate cardio a week, or 75 to 150 minutes of vigorous cardio, or a mix. For weight loss and keeping weight off, more tends to work better, often above 250 minutes a week, but you build up to that gradually.
The WHO guidelines on physical activity apply to adults living with chronic conditions too, and they make an important point for beginners: doing some activity is better than none, and doing a little more each time brings extra benefit.
| Moderate cardio per week | What it looks like | What to expect |
|---|---|---|
| Under 150 minutes | A 10 to 20-minute walk or ride on most days | Clear health benefits for people who were inactive; a good starting point, not a failure |
| 150 to 250 minutes | 30 to 35 minutes, five days a week | Helps prevent weight gain and adds to the effect of a moderate change in eating; only modest weight loss on its own |
| Over 250 minutes | About 50 minutes, five days a week, or shorter sessions twice a day | Linked to clinically meaningful weight loss and to better weight maintenance |
Moderate means you breathe faster and feel warm but can still talk in sentences. In a heavier body, a slow walk up a slope may already be moderate, and that counts in full.
The minutes do not have to come in one block. Three 10-minute walks across a day count the same as one 30-minute walk, which often suits sore joints better. If the higher targets sound out of reach, remember they are where people end up after months, not where anyone starts.
LISS vs HIIT: which is better for fat loss?
Neither clearly wins. Meta-analyses comparing interval training with steady, moderate cardio find similar reductions in body fat, so the best choice is the one you enjoy and can keep doing safely.
A meta-analysis of 31 studies found that both approaches lowered total body fat by a similar amount, with no difference between them. When the interval sessions were shorter or used less energy, the steady sessions tended to come out slightly ahead, so HIIT did not reliably save time either.
The large overview of exercise reviews came to the same conclusion: when both types used the same amount of energy, it found no difference in the loss of weight, fat or visceral fat.
| LISS (steady, moderate) | HIIT (intervals) | |
|---|---|---|
| Fat loss over months | Similar | Similar |
| How it feels | Comfortable; you can chat | Hard bursts, out of breath |
| Time per session | Longer, often 30 to 60 minutes | Shorter, often 15 to 25 minutes including warm-up |
| Load on joints | Low, depending on the activity | Higher if bursts involve running or jumping |
| Best for | Beginners, joint pain, heart or lung conditions, building a daily habit | People with a base of fitness and their doctor’s go-ahead |
A word of caution about HIIT
Hard bursts put a sudden extra demand on your heart. In a study of 4,846 people with heart disease training in supervised cardiac rehabilitation, there were only three cardiac arrests in about 176,000 hours of exercise. The rate per hour was higher during high-intensity sessions, but with so few events the risk was low with both types.
So if you have heart disease, chest pain with effort, high blood pressure that is not under control, or diabetes treated with insulin, talk to your doctor before trying intervals. For anyone starting out, build several weeks of steady cardio first.
Gentle intervals: a middle way
Intervals do not have to be extreme. Once steady walking or cycling feels comfortable, you can add short pick-ups: one minute a little faster, then two minutes at your normal pace, repeated four or five times.
On a bike or in the pool, this keeps joints safe while adding variety. If you enjoy it, keep it; if you dread it, steady cardio works just as well for your fat loss.
Cardio vs weights: which is better for weight loss?
For the number on the scale, cardio usually does slightly better, because it uses more energy per session. For what that weight is made of, and for strength in daily life, weights do better. Doing both gives the best overall result.
The STRRIDE AT/RT trial gave 119 adults with overweight or obesity eight months of cardio, resistance training or both. The cardio groups lost more weight and fat than the resistance-only group. The groups that lifted weights gained lean mass, which the cardio-only group did not.
A network meta-analysis of 15 trials found the same pattern. Compared with resistance training, cardio reduced weight, waist and fat mass by a little over a kilo or centimetre more. Combined training reduced weight by about 2 kg more than resistance training alone and about as much as cardio alone, while also building lean mass. The authors recommended it whenever possible.
| Effect | Cardio | Strength training | Both together |
|---|---|---|---|
| Energy used per session | Higher | Lower | Highest per week |
| Body weight and fat | Small reduction | Smaller reduction | Similar to cardio alone |
| Visceral fat | Clear reduction | Less clear on its own | Likely reduction; fewer studies |
| Muscle and strength | Little change | Kept or gained | Kept or gained |
| Heart and lung fitness | Strong gain | Small gain | Strong gain |
If you only have time for one, begin with whichever you are more likely to do regularly, then add the other. Strength work matters more as you lose weight, because it helps you keep muscle. Our strength training for beginners page has the routines and a 12-week plan.
Cardio or weights first?
For weight loss, the order makes little difference. Do the part you care about most, or find hardest, first, while you are fresh.
A meta-analysis of trials comparing the two orders found that doing strength exercises first led to slightly larger gains in leg strength, while the order did not change improvements in aerobic fitness. That analysis did not measure fat, and there is little research suggesting the order changes how much fat you lose.
- Strength first if building strength is your main aim, or if tired legs make your strength exercises feel unsteady.
- Cardio first if a few minutes of easy cardio is your warm-up, which works well for most beginners.
- Separate days or times if a combined session feels too long. A morning walk and an evening strength routine is a perfectly good plan.
Best cardio for weight loss in a heavier body
The best cardio for weight loss is the one you can do often, for long enough, without pain. For most people living with obesity, that means low-impact options, ranked below from most to least joint-friendly in a typical heavier body.
Weight-bearing activities like walking use more energy per minute when you carry more weight. Supported activities like cycling and swimming depend less on your weight, but they let you go longer with less pain, which often evens things out over a week.
| Option | Joint load | Why it helps weight loss | Things to watch |
|---|---|---|---|
| Water walking and aqua classes | Very low | Water carries much of your weight, so you can move longer; good for joint pain | Pool access and changing rooms; choose a quiet session if that helps |
| Swimming | Very low | Works the whole body; easy on knees, hips and back | Needs some technique; a few adult lessons help |
| Cycling (stationary or recumbent) | Very low to low | Easy to control effort; ideal for intervals later | Check the bike’s maximum user weight; set the seat height correctly |
| Elliptical cross-trainer | Low | Walking-like movement with no landing; arms join in | Hold the handles when getting on and off |
| Walking | Low to moderate | Free, anywhere, uses more energy as a weight-bearing activity | Good shoes; split into shorter walks if feet or knees hurt |
| Rowing machine | Low to moderate | Legs, back and arms together; good energy use | Deep knee bend at the front of each stroke; learn the technique first |
Walking ranks lower for joints only because it carries your full weight. For most people it is still the single most useful habit, and our walking for weight loss guide takes you from a few minutes to an hour step by step. For a calmer, balance-focused variation, see tai chi walking.
If your knees are the main problem, our page on exercise with bad knees explains bike set-up, water exercise and how much pain is acceptable. If going out is hard, low impact cardio at home starts from a chair.
What about running?
Running uses a lot of energy per minute, but every stride lands with a much bigger jolt than a walking step. For most people starting at a higher weight, it is better saved for later, if at all.
Many people reach good fitness and a healthier weight without ever running. If you would like to try it one day, build months of walking and strength first, then talk to a physiotherapist.
When that day comes, our guide to running for weight loss explains run-walk intervals and how to protect your joints.
Before you start: talk to your doctor first
Most people can start gentle cardio safely, but a short check with your doctor or nurse is wise before you begin if you have been inactive and live with a health condition. They can tell you how hard you can work and what to look out for.
The American College of Sports Medicine bases its advice on three things: how active you are now, whether you have heart, metabolic or kidney disease or symptoms that might point to it, and how hard you plan to exercise. Its review also found that exercise is safe for most people and that serious heart problems during exercise often give warning signs first.
Please talk to your doctor first if any of these apply:
- known heart disease, a heart rhythm problem or chest discomfort when you exert yourself
- type 1 or type 2 diabetes, especially if you use insulin or tablets that can cause low blood sugar
- kidney disease or a lung condition such as COPD
- high blood pressure, particularly if it is not well controlled
- medicines that slow your heart rate, such as beta blockers
- new, severe or worsening pain in a joint, your back or your feet
- you plan to try HIIT or other vigorous exercise after a long inactive period
Our doctor visit checklist helps you prepare your questions, so a short appointment gives you the answers you need.
Begin each session with a few minutes of easy movement; our page on warm-up and stretching shows gentle moves for beginners.
Warning signs: stop and get help
Stop exercising, sit down and rest if you notice any of the following. If chest pain or pressure does not settle within a few minutes of rest, call your local emergency number.
- pain, tightness or pressure in your chest, or discomfort spreading to your arm, jaw, neck or back
- a racing, pounding or irregular heartbeat that feels wrong for the effort
- dizziness, light-headedness, blurred vision or feeling faint
- breathlessness that is much worse than usual or does not ease with rest
- sudden sharp pain or swelling in a joint
- signs of low blood sugar if you take diabetes medicines: shaking, sweating, sudden hunger or confusion
Normal signs of effort are different: warmth, sweating, faster breathing and tired muscles that recover within a day. These mean your body is doing the work it should.
A simple weekly cardio plan for weight loss
This plan builds from short, easy sessions to the amounts linked with weight loss over about three months. Talk to your doctor first before starting it, especially if any of the points above apply. It is general guidance, not a personal medical programme.
Pick one or two activities from the joint-friendly list and mix them however you like. Move to the next stage only when the current one feels manageable for at least two weeks.
| Stage | Cardio days | Minutes per day | Weekly total | Effort | Strength days |
|---|---|---|---|---|---|
| Stage 1 (weeks 1 to 4) | 4 to 5 | 10 to 20, in one go or in two shorter bouts | 50 to 100 minutes | Easy to moderate; you can talk in full sentences | 1 to 2 short sessions |
| Stage 2 (weeks 5 to 8) | 5 | 20 to 35 | 100 to 175 minutes | Moderate; you can talk but not sing | 2 sessions |
| Stage 3 (weeks 9 to 12 and beyond) | 5 to 6 | 35 to 50 | 175 to 300 minutes | Mostly moderate; optional gentle intervals once a week | 2 to 3 sessions |
A sample week in stage 2
| Day | Cardio | Other |
|---|---|---|
| Monday | 25 minutes on an exercise bike | Short strength routine |
| Tuesday | 30-minute walk, or three 10-minute walks | None |
| Wednesday | Aqua class or 25 minutes of swimming | None |
| Thursday | 20 minutes on the elliptical or bike | Short strength routine |
| Friday | Rest, or an easy stroll | Stretching |
| Saturday | 35-minute walk with a friend or family member | None |
| Sunday | Rest | None |
Making the plan work
- Increase one thing at a time. Add minutes, or add effort, but not both in the same week.
- Repeat a stage as often as you need. Many people spend six weeks or more in stage 1, and that is completely fine.
- Keep two easier days. Rest days help joints and muscles adapt, and they make the habit sustainable.
- Write it down. Minutes per week and how you felt are more useful early measures than weight.
If you prefer guided sessions, our free Start, Build and Strong workout videos follow the same idea of building up level by level.
Cardio works best with good food
The largest and most lasting effect on weight comes from combining regular cardio with an eating pattern you can keep up. Exercise alone moves the scale a little; food changes alone move it more; together they work best and protect your muscle and heart.
You do not need a strict diet. Filling meals built on vegetables, beans, whole grains and a protein source, regular meal times and fewer sugary drinks make a real difference. Our free 7-day eating plan shows what that looks like in practice, without crash diets.
If you are doing the cardio and eating well but the scale has not moved for weeks, our page on why you are not losing weight walks through the common reasons and what to adjust.
How Obesity Foundation helps you move and lose weight
We help people lose weight and get healthier with good food, suitable exercise and walking. Everything we offer is free, because we are a non-profit.
- Workout videos at your level: follow-along cardio and strength sessions in three levels, from seated starts to full workouts. Get the free workout videos.
- An eating plan that fits: everyday meals that support your cardio and keep hunger under control. Ask for your free eating plan.
- Your own progress log: track minutes, walks and how you feel, privately, week by week. Open your free Club account.
- Personal questions answered: unsure which cardio suits your body or health? Book a free video meeting (in English).
Start with ten minutes of something you can repeat tomorrow. That small, steady step is how every good cardio habit begins.
Frequently asked questions
Does cardio burn fat or muscle?
Regular cardio mainly reduces fat, including the deep visceral fat around your organs. When you also eat less, some lean tissue is lost along with the fat, and cardio alone does little to stop that. Adding two strength sessions a week and enough protein helps you keep your muscle while the fat goes down.
Should I do cardio or weights first for weight loss?
For weight loss, the order makes little difference, so choose what suits you. Doing strength first may give slightly larger gains in leg strength, while aerobic fitness improves equally either way. Many beginners like a few minutes of easy cardio as a warm-up, and splitting cardio and strength over different times of day works well too.
Is HIIT better than steady cardio for losing weight?
Not clearly. Meta-analyses find similar reductions in body fat with interval training and steady, moderate cardio, especially when both use a similar amount of energy. HIIT puts more sudden demand on the heart and often on the joints, so build a base of steady cardio first and talk to your doctor before trying intervals if you have a heart condition, high blood pressure or diabetes.
Why am I hungrier since I started doing cardio?
Many people eat a little more after starting regular exercise, often without noticing, because the body partly makes up for the energy used. In one trial this added up to roughly 90 to 125 kcal a day. Planning filling meals with protein and fibre, and not treating workouts as permission for treats, helps you keep the benefit.
How many days a week should I do cardio to lose weight?
Most plans spread cardio over five or six days a week, with one or two easier or rest days. Short daily sessions are often easier on the joints than a few long ones, and three 10-minute bouts count as much as one 30-minute session. Start with what you can manage and add a few minutes each week.
Is swimming good cardio for weight loss?
Swimming is excellent cardio, especially if your knees, hips or back hurt, because the water supports much of your weight. Because it hurts less, many people can swim or water-walk for longer and more often than they could walk on land. Water walking and aqua classes are good options if you do not swim well.
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