My 100 Mile Swim Update | What I Discovered About Calorie Burn Rate

Long distance swimming

My commitment to swimming 100 miles this year is goingWell ‘swimmingly’.  Ok, cheesy, I get it, but it’s true, I’m very happy with my progress.  So far I’ve logged a total of 27 miles in the pool, down and back, down and back, staring at the same black line at the bottom of the pool, just in case I happen to get off course… of course..  

I’ve set a goal to swim at least 8.33 miles per month before next New Years Day.  I’ve been swimming very consistently for over 20 years, but I’ve never really set a distance goal or actually tracked the details of my swims.  So, this year I’ve made it a priority to change that.

Is Swimming a good exercise for burning calories.

I’ve often wondered how swimming compares to other cardiovascular exercises when it comes to calorie burning.  So far, my 27 miles of ‘1 part freestyle to 1 part breaststroke’, has yielded the evaporation of 12,682 calories.  Not too shabby.  

But is this normal?

Well, according to the freestyle stroke typically burns 300 calories in 30 minutes, while breaststroke burns an average of 200 calories in 30 minutes. 

My experience has been different

The 27.187 miles I’ve swam so far this year has taken 969.39 minutes, or roughly 16.16 hours.  The math works out to be 13.08 calories per minute, so if I multiplied that calorie burn rate, times 30 minutes, it would be an average of 392 calories.

This is clearly more calories than what the article found, but I have to believe there are a number of different variables that skew these numbers, such as;

Age and body chemistry

Swimming Stroke

Swimming Venue

Age and Body Chemistry affects calorie burn rate

I would guess a swimmers age and build play a significant factor in the amount of calories lap swimming burns?  I’m 52, and of average height and build.  I don’t think I was built to be a swimmer, but I’ve adapted rather well.  

Now, Michael Phelps, that’s a man with a physique built for swimming.  His massive hands and feet help him propel through water with efficiency, and his extra long torso provides buoyancy and increased lung capacity.  And I would guess, Michael Phelps’ body chemistry burns calories, even in the resting position, more purposefully than us mere- ‘mortals’.  

Different swimming strokes affect calorie burn rate.

I found this cool calorie burning tool you can use to see the ‘burn rate’ of your favorite exercise. 

This shows a vigorous 30 minute swim would burn an average of 420 calories, which seems more akin to where I thought it should be. 

Since I swim freestyle and breaststroke, perhaps the ‘burn rate’ increases, compared to if I were to swim butterfly or backstroke..  Throw my age and body chemistry in there, and the variance from the article could be even more exacerbated.

Open water swimming increases caloric burn rate.

Swimming venue matters too, I promise.  Swimming in a well defined pool lane with excellent visibility and absent a school of lurking, scaled, sea creatures is vastly different than swimming in an ‘open water’ environment’.

Open water swimming, unlike it’s illegitimate second cousin, ‘the indoor swim’ is vastly difficult to stay on course.  The underwater currents and lack of vantage points often cause you to swim off course, and subsequently farther than you would if you were in a pool.   And, like I said about the lurking sea creatures, it’s just more daunting and stressful swimming in open water.

These variables alone, cause most swimmers heart rates to increase, and as a result, cause a higher caloric burn rate.  

Is my average heart rate while swimming, healthy or not?

While I’m no doctor, I have read that your heart beats slower in water than on land because the cooler water lowers your body temperature and slows your metabolism. 

I was not aware of this either, but it makes perfect sense:  

As you swim, your heart rate increases. This increases the supply of blood to your arms, legs, and other parts of your body. The increased circulation helps all of your muscles perform more efficiently and become stronger. 

 ~Barron Swim School~

My average heart rate for the 27 miles I’ve swam was 122.90.  In case you’re wondering what the ideal heart rate is for various age groups during a vigorous swim, here is what I found in a post from  

Swimming heart rate

How has swimming 27 miles affected my body weight?

At the start of my 100 mile ‘Swim to Nashville’ Journey I weighed 184 pounds.  My weight generally remains pretty consistent, in fact I believe I’ve weighed around 180 for the last 10 years.  

But, I wanted to track what the effects of ‘100 miles of swimming’ would have on my body weight, and so far, I’ve gained 2 pounds.  Yes, it surprised me too.  Maybe it’s two pounds of muscle?  Or, maybe it’s the impact the Oreo’s and the Pimento Cheese sandwiches have had, who knows.   

Either way, since I’m planning on swimming 100 miles this year, the 2 extra pounds doesn’t worry me.  

So, after 27 miles of swimming since the beginning of the year, I’m happy with my progress.  I look forward to continuing to track these metrics, and to see if they divert from the averages over these next 73 miles.  

Time will tell, but the tracking of my swims is keeping me accountable and motivated and I’m enjoying this ‘self-inflicted’ challenge.

Are you tracking any long term health goals for 2023?  




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