How Much Do I Sweat? I Conducted a Scientific Experiment to Find Out!

This post begins with a fantastic workout. I started by doing the signature program on my Bowflex Max Trainer: the 14-minute Max Interval program, which alternates short bursts of high intensity work with longer recovery periods. It’s a challenging 14 minutes…


…during which I burned 273 calories!


Then I switched to the another program on my Max Trainer, the Stairs program – you know, because I’m training for my upcoming stair races. This program is 15 minutes long. I snagged an overhead selfie afterwards…


…before realizing I burned another 198 calories:


But my workout wasn’t over yet! I grabbed my keys and iPod, and headed outside. I went for a 31-minute run in the park near my house…


…covering 2.7 miles… and 506 more calories!


It was a tremendous workout… and it was all in the name of science. Let me explain. A few days prior, I had done a workout video starring my friend (and Bowflex fitness advisor) Tom Holland. I noticed during the video that was he sweating more than the others around him, so I jokingly gave him a hard time about it on Twitter. (Follow me on Twitter! And Tom! And I’ll tell you more about the workout video in an upcoming post!)

During the course of our Twitter exchange, Tom said that when he exercises, he loses four pounds of fluid an hour through sweating. FOUR POUNDS! And since I’m a curious sonofabitch, I decided I needed to figure out how much I sweated during an hour.

So, a few nights later, I conducted an experiment. First, I drank lots of water. Then I weighed myself, naked. Then I did the workout described above. You’ll note it lasted exactly one hour (14 minutes + 15 minutes + 31 minutes = 60 minutes = 1 hour). I did not drink at all during that hour (which is why I drank lots beforehand). Then, I stripped off all my wet and sweaty clothes, used a towel to absorb any excess sweat off my skin, and weighed myself naked, again.

I was 4.2 pounds lighter. I lost 4.2 pounds of fluids from sweat! Kinda disgusting, but also totally cool info to have. I mentioned before that I was a curious sonofabitch, and I’m also a competitive sonofabitch, too: and my experiment shows that I sweat more than Tom! I don’t think that’s something to necessarily be proud of, but I win nevertheless.

I’d like to issue a challenge to everyone out there: figure out how much you sweat. Does anyone sweat more than me? 

Tom told me on Twitter that having information about how much you sweat can help you with your hydration strategy. I replied by joking that I was getting most of my hydration from McDonald’s Shamrock Shakes, because it’s that time of year. And Tom replied by saying that’s fine – as long as I climbed the stairs in the Empire State Building after every shake!

And that made me curious whether climbing the stairs in that building would be enough to burn off the calories from a Shamrock Shake. So I figured that out too.

I typically burn around 1,200 calories during a stair training session in the Aon Center, where I climb a 51-story stairwell 4 times. That means I burn 5.8 calories per story. The annual Empire State Building Run-Up race ends on the 86th floor observation deck, so I’d burn 498.8 calories to get there from the lobby. (Not too shabby!)

A large Shamrock Shake (because let’s face it, if I’m going to drink a Shamrock Shake, it’s going to be a large one) has a whopping 820 calories. Whoa. So one climb up the Empire State Building wouldn’t cover it. A small Shamrock Shake has 530 calories, so if I climbed it once, and, say, did some burpees at the top or something, then we’d be in business!

All this is a moot point because I’ve never done the Empire State Building race (I’ve applied, but it’s very hard to get a bib) and I can’t recall the last time I’ve had a Shamrock Shake. But sometimes hypothetical math can be fun.

And there was nothing hypothetical about the very real workout I did for my sweat experiment. That was a 977-calorie workout!

Keep it up, David!


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2 Responses to How Much Do I Sweat? I Conducted a Scientific Experiment to Find Out!

  1. adam says:

    More math nerdery:

    It may not all be sweat – there’s also the 977 calories you burned!

    Presuming those calories were were protein or carbs (4 cal/g) and not fat (9 cal/g) then:
    977cal / (4 cal/g) = 244 grams = 0.54lbs of body mass burned off.
    Unless I’m confusing cal and kcal which I might be.

    If the remaining 3.7lbs is water, that’s 1.7 liters of fluid lost in the workout. It would be interesting to also weigh your clothes and towels before/after the workout. Though I imagine some of your sweat flies off or evaporates, so your method of total body weight is probably better.

    • David says:

      Love the nerdery! (As always.) Most fitness authorities say that burning 3500 calories = losing one pound. By that scale, I burned off about 1/4 of a pound of body mass – and hey, every bit counts! I forgot to mention in the post that 4 pounds of water equals 1/2 gallon. So that’s another cool nerdy metric… although I think I’ll pass on weighing clothes post-workout if I do this experiment again!

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