Surprising Factors: Why Am I Gaining Weight from Swimming?

Marjan Sokolovski

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Gaining Weight from Swimming

Swimming is often hailed as one of the best full-body workouts, renowned for its ability to help shed excess pounds and enhance overall fitness. 

However, what happens when you find yourself gaining weight instead of shedding it through regular swimming? 

This unexpected turn of events can be perplexing, leaving swimmers bewildered and questioning the effectiveness of their exercise routine. In this blog post, we’ll dive deep into why am i gaining weight from swimming. 

From muscle development and compensatory eating to hormonal imbalances and even underlying medical conditions, we’ll explore the multifaceted factors that might lead to this surprising phenomenon. 

By gaining a comprehensive understanding of these factors, you can make informed decisions about your swimming regimen, diet, and overall health to ensure that swimming continues to be a positive contributor to your fitness journey. So, stay focused. 

Is Gaining Weight After Swimming Normal?

Gaining weight after swimming can be normal, but it largely depends on various factors such as diet, intensity, and frequency of swimming, as well as individual metabolism. 

Swimming is an excellent form of exercise that burns calories and helps build lean muscle mass, which can contribute to weight loss or weight maintenance. 

While gaining weight after swimming can be normal, it’s important to monitor your diet and maintain a balanced lifestyle to ensure that any weight changes are in line with your health and fitness goals.

Why Am I Gaining Weight from Swimming

Why Am I Gaining Weight from Swimming

Gaining weight from swimming can be a perplexing experience, but there are several reasons why this might occur:

Muscle Development

Swimming is a full-body workout that engages various muscle groups. Over time, your body may build lean muscle mass as a response to regular swimming. 

Muscle is denser than fat, so an increase in muscle can lead to weight gain on the scale. This is a positive type of weight gain as it makes you stronger and more toned.

Increased Appetite

After intense swimming sessions, you may find yourself feeling ravenous due to the energy expenditure. 

If you consistently consume more calories than you burn during swimming, it can result in weight gain. It’s important to maintain a balanced diet to prevent excessive calorie intake.

Water Retention

Swimming can cause temporary water retention due to the body’s response to the physical activity. This added water weight might reflect on the scale but is not indicative of fat gain. 

It is important to remember that this weight fluctuation is temporary and typically resolves itself.

Calorie Underestimation

Swimmers may underestimate the number of calories burned during their workouts. This can lead to overcompensation by consuming more calories than needed, which can contribute to weight gain.

Stress and Cortisol

Intense training, including swimming, can lead to elevated cortisol levels, a stress hormone. High cortisol levels can promote fat storage, especially in the abdominal region. 

It’s crucial to manage stress levels through relaxation techniques and adequate sleep to mitigate this effect.

Gaining weight from swimming is not uncommon, and it often reflects changes in muscle mass, temporary water retention, or imbalances in caloric intake and expenditure.

Understanding Swimming Weight Gain

Understanding Swimming Weight Gain

Swimming, which is typically considered an effective form of exercise for weight management, can sometimes lead to weight gain due to various less common factors:

Hormonal Imbalance

Hormones play a crucial role in regulating body weight. Intense and prolonged swimming, particularly for competitive swimmers, can disrupt hormonal balance. 

Overtraining, coupled with inadequate rest and recovery, may lead to hormonal imbalances that can trigger weight gain. This is more likely to affect professional athletes and not casual swimmers.

Compensatory Eating

Some individuals who engage in swimming as a form of weight loss may experience compensatory eating. 

They might feel entitled to indulge in high-calorie foods because they swam, thereby negating the calorie-burning effects of their workout. This overcompensation can lead to unexpected weight gain.

Underlying Medical Conditions

Unexplained weight gain from swimming can sometimes be attributed to underlying medical conditions. 

Conditions like hypothyroidism or polycystic ovary syndrome (PCOS) can affect metabolism and lead to weight gain even when engaging in regular physical activity like swimming.

Muscle and Fluid Balance

Rarely, some individuals may experience imbalances in their body’s fluid and electrolyte levels. 

This can lead to water retention and fluctuations in weight. These imbalances might be due to medical conditions or medications and can be addressed through medical intervention.

It’s essential to remember that these reasons for weight gain from swimming are relatively uncommon and typically not experienced by the majority of swimmers.

Muscle Development While Gaining Weight Swimming

Muscle development is a common outcome of regular swimming, and it can be an important aspect of gaining weight while swimming:

Full-Body Workout

Swimming engages multiple muscle groups simultaneously, including the legs, core, back, shoulders, and arms. This full-body workout promotes muscle development throughout the body. 

The constant resistance of the water provides a unique and effective form of resistance training.

Lean Muscle Mass

Swimming tends to promote the development of lean muscle mass. 

Lean muscle is denser than fat, which means that as you gain muscle, your body weight may increase, even if your body fat percentage decreases.

This can make you appear more toned and athletic while contributing to overall weight gain.

Upper Body Strength

Freestyle, butterfly, and backstroke strokes heavily involve the upper body, promoting the growth of the muscles in the arms, shoulders, and upper back. Swimmers often develop defined and strong upper bodies.

Core Strengthening

The constant engagement of the core muscles to stabilize the body in the water enhances core strength. This not only improves swimming performance but also contributes to a more sculpted midsection.

It’s important to note that while muscle development can lead to weight gain, it is typically considered a positive form of weight gain as it improves strength, endurance, and overall physical fitness.

Fluid Retention Regarding Swimming GainWeight

Fluid Retention Regarding Swimming GainWeight

Fluid retention can be a factor contributing to weight gain in some swimmers, and this phenomenon is influenced by various factors:

Hydrostatic Pressure

When you are immersed in water, the hydrostatic pressure exerted by the water on your body can influence fluid distribution. 

This pressure can lead to the displacement of blood and bodily fluids from your extremities to your core. 

Consequently, you may experience swelling and mild fluid retention in the hands, feet, and lower limbs after swimming.

Sodium and Electrolyte Levels

Intense swimming can lead to significant electrolyte loss through sweat, particularly sodium. 

After swimming, it’s common for swimmers to replenish sodium levels by consuming salty snacks or sports drinks. 

An increase in sodium intake can lead to fluid retention as the body holds onto water to balance sodium levels.

Prolonged Immersion

Competitive swimmers who spend extended periods in the pool may experience a more pronounced form of fluid retention due to prolonged immersion. 

The skin’s exposure to water for an extended time can cause it to absorb some water, contributing to temporary weight gain.

Dehydration and Water Retention

Paradoxically, dehydration can also lead to water retention. When the body is dehydrated, it tends to hold onto the available fluids to prevent further fluid loss. 

Swimmers who don’t maintain adequate hydration can experience this effect, leading to unexpected weight gain after their workout.

It’s important to recognize that fluid retention, in most cases, is temporary and should not be confused with fat gain. 

It can vary from person to person and is influenced by factors like swim duration, intensity, and environmental conditions.

Monitoring and Managing Swimming and Weight Gain

Monitoring and Managing Swimming and Weight Gain

Monitoring and managing weight gain while swimming can be crucial for achieving your fitness and health goals. Here are some unique tips to consider:

Track Body Composition

Instead of solely relying on the scale, monitor your body composition. This can be done through methods like dual-energy x-ray absorptiometry (DXA) scans or bioelectrical impedance scales. 

These assessments can differentiate between muscle and fat mass, providing a more accurate picture of your progress.

Nutrient Timing

Pay attention to nutrient timing around your swimming workouts

Consuming a balanced meal with carbohydrates and protein before and after your swim can help support muscle development and recovery while minimizing overeating. 

It can also help regulate energy levels throughout the day.


Consider periodization in your swimming training. Periodization involves cycling through different training phases, including periods of high-intensity training, recovery, and maintenance. 

This approach can prevent overtraining, hormonal imbalances, and excessive muscle gain that might lead to weight gain.

Consult a Sports Nutritionist

A sports nutritionist can create a personalized nutrition plan tailored to your swimming goals and body composition. 

They can help you strike the right balance between calorie intake and expenditure, ensuring that you achieve your desired weight and performance without undue weight gain.

Address Stress and Hormones

Prolonged stress and hormonal imbalances can contribute to weight gain. 

Implement stress-reduction techniques, such as meditation or yoga, and consult a healthcare professional if you suspect hormonal issues. Addressing these factors can help you maintain a healthy weight.

Monitoring and managing weight gain while swimming involves looking beyond the scale, optimizing your nutrition, and addressing stress and hormonal factors.


Does swimming increase weight?

No, swimming typically does not increase weight. In fact, it’s an excellent exercise for weight management and can help you burn calories and build muscle, which can contribute to weight loss.

Does swimming make you gain weight?

Swimming is unlikely to make you gain weight. If you’re experiencing weight gain while swimming, it may be due to other factors like dietary choices or muscle development, rather than the exercise itself.

Does swimming make you weigh more?

Swimming can lead to an increase in muscle mass, which might slightly increase your weight, but it’s a positive change. Muscle weighs more than fat, and increased muscle can boost your metabolism and improve overall health.

Why did I start swimming and gain weight?

Weight gain while swimming might be due to dietary habits or an increase in muscle mass. Evaluate your calorie intake and ensure it aligns with your fitness goals to achieve desired results.

Why do swimmers get fat?

Swimmers don’t typically get fat. Weight gain can occur when calorie consumption exceeds the calories burned through exercise. 

To avoid this, maintain a balanced diet and monitor your nutrition while swimming to support your fitness goals.

Wrapping Up

The weight gain that occasionally accompanies swimming is not necessarily a setback but a result of several complex factors. 

Understanding that muscle development, compensatory eating, hormonal imbalances, and underlying medical conditions can play a role can empower you to navigate this situation effectively. 

Remember that the number on the scale doesn’t always tell the whole story, and it’s essential to focus on overall health and fitness. 

If you’re concerned about unexpected weight gain from swimming, consult with a healthcare professional who can provide guidance and ensure that you’re on the right track to achieving your fitness goals. 

With the right knowledge and a holistic approach to your well-being, swimming can remain a valuable tool in your journey toward a healthier, fitter you. Thank you so much. 

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Marjan Sokolovski

I am a professional swimming coach who has been coaching for over 20 years. I have coached athletes in the Olympics and Paralympics, and I have also helped to train people across the world. I started my coaching career by teaching swimming lessons at a local pool. I was really passionate about teaching people how to swim, but I quickly realized that this wasn't enough for me. I wanted to make a difference in people's lives and help them achieve their goals. I started working with athletes in high school, college, and then professionally. The best part about coaching is that you get the opportunity to work with so many different types of people from all walks of life - it's just incredible! LinkedIn

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