Swimming for Weight Loss: How Does it Work?

by Marixie Ann Obsioma, MT, undergrad MD on January 13, 2021
Last updated on May 23, 2021

When it comes to activities that can help you lose weight, swimming probably isn’t at the top of your list. For sure, you have thought about running. How about strength training? Definitely. But, did you know that splashing around can also be a serious fat burner? 

Swimming for Weight Loss How Does it Work

Swimming is an exercise for people of all ages! It can be easy and affordable. You can go at your own pace! It is one of the best activities you can do to tone and slim your entire body. You use your arms and legs to stay afloat and your back muscles for propelling. Plus, if you are burnt out on other types of cardio such as walking, running, or jogging, swimming can be a welcome change! 

Best of all, swimming does not only help you get a good physique, but its benefits also extend to overall health! Here’s what makes swimming a stellar workout for weight loss, plus several other health benefits and tips for diving in. 

How Swimming Can Help You Lose Weight? 

Similar to other cardiovascular routines, swimming burns calories and helps you slim down. But unlike, say walking or running, moving through the water creates extra resistance, forcing you to use more muscles. 

Swimming can tone your upper body, lower body, and core all at the same time. It gives you a full-body workout and more overall muscle definition versus other cardio routines. By building muscles, you are also burning more calories. 

What’s more? It does not take very long to reap the fat-burning benefits of swimming. Evidence suggests that a middle-aged woman can lose a significant amount of body fat in as fast as 12 weeks by swimming for 60 minutes 3 times weekly (1). 

How Calories Are Burned During Swimming? 

The rate at which your body burns calories for energy is termed as metabolism. When you exercise, your metabolism increases. How much effect this has and how long it will last depends on several individual factors, including your age, gender, body composition, and the activity that you are performing. 

For swimming, a 150-pound person can burn approximately 400 calories, on average, during an hour-long swim at a moderate pace. This can increase to 700 calories if vigorously done. However, these numbers don’t hold true for everybody. The number of calories you burn during swimming will also depend on your weight, duration of exercise, stroke used, and swim efficiency. 

What Stroke Burns The Most Calories? 

You will burn more calories if you swim faster and cover more distance. The fastest swim stroke is freestyle, which can torch around 404 calories within 30 minutes. But, that doesn’t mean you must opt for the freestyle every time you get into the pool. 

Again, the number of calories you burn will also depend on duration and frequency. If you prefer the breaststroke, which can help you burn approximately 367 calories within 30 minutes, you just have to swim a little longer. 

Compare these numbers to just 100 calories for 30 minutes of brisk walking or 300 calories for 30 minutes of running at 6 miles per hour. You’ll notice how effective swimming is in burning calories compared to other exercises. Mix up your strokes to work different muscles and keep things interesting! 

Can Swimming Help You Burn Belly Fat? 

Keep in mind that any activity that burns calories will help you shed fat all over, which includes your middle area. Some swimming techniques can specifically target your core like flutter kicks for lower abs and butterfly kicks for your obliques. 

Evidence showed that women who swam 3 times weekly lost more fat around their waists and hips compared to those who walked 3 times weekly (2). What’s more is that water-based exercises are low-impact, so they are easier on your lower extremities. Swimming can give you cardio and muscle building without the heavy wear and tear on your body that you can get from land-based activities such as running and weight lifting. 

How Much Do You Have to Swim to Slim Down? 

As mentioned earlier, the intensity of your workout can greatly impact the rate of your weight loss. Swimming vigorously for one hour can help you burn approximately 700-800 calories. Do that 4 times weekly and you can expect to lose a whopping 3-4 pounds in a month. 

However, if you prefer to enjoy a less intense approach, you can swim at a moderate pace for 30 minutes to burn around 200-250 calories. Do that 4 times weekly and you’ll lose a little more than a pound in a month! 

But of course, we are all different and a study suggests that some people may lose more or less weight than others, even after doing the same amount of exercise (3). However, making routines, like swimming, a part of your regular daily activity can certainly help you reach or maintain a healthy weight. If you want to drop pounds, consider doing moderate or vigorous exercises for an hour daily. 

Other Benefits and Advantages of Swimming 

1. Improves Cardiovascular Health 

Cardio exercises involve the heart, lungs, and circulatory system. A thorough routine, such as one that features swimming, will include this type of exercise. 

Evidence shows that swimmers have half the mortality rate of people who are inactive or living a sedentary lifestyle (4). Data from 2016 shows that swimming can help lower and control blood pressure and blood glucose levels (5).  

2. Appropriate for People with Arthritis, Injuries, and Other Conditions 

Swimming is a safe exercise option for people with disabilities, arthritis, injury, and other issues that make high-impact routines hard or impossible. Swimming may even help decrease pain or hasten your recovery from an injury. 

Evidence showed that people with osteoarthritis had significant reductions in joint pain and stiffness, and experienced less physical limitation after swimming and cycling (6). Swimming also has many of the same benefits as frequently prescribed land exercises. So, if land activities are difficult for you, try exercising in the water! 

3. Excellent Option for People with Asthma 

The humid environment of indoor pools makes swimming an excellent activity for people with asthma. It is also a good breathing exercise that requires you to hold your breath, which may help expand your lung capacity and gain control over your breathing (7). 

But be careful of pools treated with chemicals like chlorine. Some studies suggest that it can increase your risk of asthma (8). Check with your doctor first and if possible, look for a pool that uses saltwater. 

4. Beneficial for Patients with Multiple Sclerosis

Patients with multiple sclerosis (MS) may also find this water activity very helpful. Water makes the limbs buoyant, giving them support during exercise. Water also gives a gentle resistance. Evidence showed that a 20-week swimming program can help reduce pain for patients with MS (9). They also showed improvements with many symptoms, including depression, fatigue, and disability. 

5. Improves Sleep 

Swimming can help you sleep better at night. Evidence showed that older people with insomnia had a boost in sleep and quality of life after engaging in regular aerobic exercise, which includes swimming, bicycling, Stairmaster, elliptical, and more (10). Swimming is very accessible to people who deal with physical issues that make other routines, such as running, less interesting. This is a good option for older adults looking to enhance their sleeping patterns. 

6. Enhances Mood 

Exercise releases endorphins, which help us improve our mood. Swimming may likewise boost confidence and social skills that can greatly impact one’s self-esteem. 

Experts say that participating in a 12-week water program can help enhance the mood of people with dementia (11). Swimming and other aquatic routines are not just psychologically beneficial for those with a neurocognitive disorder, it has been shown to boost mood in other people too! 

7. Manages Stress

Exercise is an excellent way to relieve stress and anxiety. It can also redirect one’s mind away from troubling thoughts. 

Experts in Taiwan surveyed a group of swimmers before and right after a swimming session. Out of more than 100 people asked, 44 said they are mildly depressed and feeling stressed. After swimming, the number of people who still reported feeling stressed decreased significantly to just 8 (12).  

Though newer studies are needed, even 20 minutes of physical activity weekly can help you feel more relaxed (13). 

8. Safe for Pregnant Women 

Pregnant women and their babies can also enjoy and reap some of the wonderful benefits of swimming! An animal study showed that swimming can alter the brain development of an offspring. It can protect babies against hypoxia-ischemia, a type of neurological issue (14). Aside from these promising benefits to the baby, swimming is an activity that can be enjoyed safely in all3 trimesters. 

Another evidence showed no adverse effects on pregnant women swimming in chlorinated pools (15). In fact, if they swam during their early to mid-pregnancy, they are less likely to have preterm labor and congenital malformations 

However, keep in mind that while swimming is generally considered safe for most pregnant women, some may have activity restrictions due to complications in pregnancy. It is best to talk to a doctor before embarking on a new exercise routine. 

9. Enjoyable Routine for Kids 

Considering that the obesity rate is increasing in children too, it is important to engage them in aerobic exercises for at least 60 minutes daily (16). Swimming is a fun activity and does not necessarily feel like a formal workout. Kids may enjoy doing structured swimming lessons during summer break. Unstructured swim time is yet another solid option to keep your kids moving! 

10. Affordable and Accessible

Swimming is very affordable compared to some other routines such as cycling. Several pools offer reasonable rates to join. Other towns and cities even offer public pools for free or at discounted rates. Check with your employer or health insurance too! Some offer reimbursements for joining a fitness program. 

Swimming in a lake or ocean is yet an attractive option. However, safety should always be a priority. Ensure supervision when dipping in open waters.  

How to Get the Most of Your Swimming Workout? 

Whether you are swimming to lose fat, increase muscle tone, or just change up your routine, here are some tips to get the best results. 

1. Swim Every Morning

A morning swim isn’t feasible for everyone, but it is certainly worth a try if you can access a pool before work. Swimming early in the morning will leave your body in a fasted state to utilize fat stores for energy. It is an excellent full-body workout, so you can expect great results too! 

2. Swim Harder and Faster

Swimming helps you burn a lot of calories when you are just beginning. But as your swimming skills improve and you become more efficient, your heart rate will no longer increase as much. The solution is to swim harder and faster. 

It is best if you can wear a waterproof fitness tracker to monitor your heart rate while exercising in the water. Your target during a moderate pace exercise should be 50-70% of your maximum heart rate. The formula to determine your maximum heart rate is 220 minus your age. 

3. Join A Swim Class

Learning proper stroke techniques can likewise help you swim at a moderate pace. You can contact a community center near you or YMCA for affordable swimming lessons. You may also sign up for good training through the American Red Cross. 

4. Switch Up Your Routine 

If you swim at the same pace and use the same stroke over and over again, your body will eventually hit a plateau. Step out of your comfort zone and modify your routine! This way, you will use different groups of muscles and help maximize your results. 

5. Swim Four to Five Days Weekly 

The more physically active you are, the better for weight loss. This applies whether you are swimming, walking, running, jogging, or using cardio equipment. The frequency of swimming to slim down is the same as other cardio routines, so aim for 4-5 days weekly for the best results. 

6. Start Slow 

Start slowly by swimming 15-20 minutes every other day, and then gradually increase to half an hour five days weekly, as your body permits. If you start a new swimming routine at a very high intensity, fatigue and muscle soreness can cause you to give up. 

7. Mix Swimming With Water Aerobics

You don’t need to swim every day to get results. You can alternate swimming with water aerobics. These are excellent low-stress activities to help you keep moving on recovery or off days. 

8. Use Floats or Pool Noodles

If you are not an excellent swimmer, swim laps in the pool using kickboards, life vests, or pool noodles. These will help you float as you use your arms and legs to move through the water. 

9. Lift Water Weights

If you want to lose weight and tone up faster, do some bicep curls using water dumbbells in between laps. The water creates resistance, which is good for building strength and endurance. 

10. Adjust Your Diet 

With any weight loss program, you must burn more calories than you consume, and swimming is no exception! You still have to make adjustments to your diet. 

But be careful not to overdo your calorie restriction. Swimming takes too much energy, so you will need to refuel with food. Also, cold water can cause your appetite to increase substantially after a session. If you feel hunger, add more vegetables to your plate, get a protein shake, and stay away from snacking. 

The Bottom Line

If you have just started an exercise program to lose weight or if you are looking to try something new, jump in the pool! Swimming has a host of health benefits not just for your body, mind, and soul! 

As soon as you get the basics down, try swimming more laps at a pace that keeps your heart rate elevated. Don’t forget to drink lots of water and take breaks if needed. Most of all, have fun! 


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