Mythbusting Sweatbusting

Today at the gym I encountered a woman wiping down equipment after each use in a way that seemed excessive. She sprayed her rag with disinfectant after each wipe, using as many as six sprays per machine. I shouldn’t have gotten so annoyed by her attempt at hygiene and courtesy, but I did. I had to wait extra time for a machine she used before me, and I also felt her cleaning was unnecessary. She was wearing pants and didn’t seem to be sweating much, if at all, so was it really important to wipe down the leg pads? Even if sweat had gotten through, did the pad really need to be disinfected? Wasn’t she just adding, if only minuscully, to the problem of super-resistant bacteria?

Source: wikihow.com

To hopefully prove myself in the right, as well as increase my scientific knowledge, I decided to research these questions. After reading several articles, I have concluded that I may not have been 100 percent right, but I wasn’t entirely wrong either.

Fear not:

Philip Tierno, professor of microbiology and pathology at NYU, points out, “Of the 60,000 or so germs that people may come in contact with, only about 1 percent are potentially dangerous.”¹

Except that...

Unfortunately, that still leaves many dangerous possibilities. Sweat can carry Hepatitis B,² and the frightening bacteria MRSA “can survive on gym machines between users.”³ Furthermore, a New York Times article reports, “At any given time [...] one person in three in the United States suffers from a skin disease that can be spread to others, even while in the incubation stage.”⁴

Fear Not:

One scientific finding I read about in two articles is that sweat contains a “natural antibiotic,” Dermcidin, that “can kill a range of bacteria.”⁵ So if Jane Sixpack at the gym has spread Hepatitis B through a cut in her finger, maybe the sweat she’s also producing could destroy the virus before Joe Jogger steps on the treadmill. 

Except that...

I didn’t read anything about everyone’s sweat being able to kill every kind of pathogen. When I wasn’t sure if sweat even carries bacteria and viruses (I thought it probably did, but didn’t want to assume), these articles seemed to suggest it doesn’t, adding strength to my position. But that would be stretching this finding too far. The fact that one compound in sweat can kill a range of bacteria doesn’t mean all sweat is bacteria-free, to say nothing of viruses.

Fear Not:

A Men’s Health article stated, “You only need to worry about bacteria if you touch your mouth, eyes, nose, or any cuts before washing your hands.”⁶ Perhaps instead of using disinfectant on every touched surface after any use of a machine, gym users should just wash their hands after their workout, and maybe mid-way through as well if they’re moving between different exercises.

Except that...

If you’re like me and don’t bother with gym towels, it’s hard to avoid touching your face when you’re sweating. The simple solution there, I suppose, is to start bothering with gym towels, but that doesn’t solve the problem of an exposed cut or abrasion touching equipment contaminated by pathogens. Not a problem for every type of exercise, but a problem for some.

Source: abduzeedo.com

Fear Not:

From a certain perspective, it’s not the tiny chance of picking up something serious like MRSA at the gym that should be frightening, but the problems caused by the overuse of antibiotic and antiviral products and medications. According to Dr. Brad Spellberg of the L.A. Biomedical Research Institute, “The more antibiotics people are exposed to, the greater the risk that they are going to acquire and keep in their body bacteria resistant to antibiotics.”⁷ Again, the idea is to wash your hands often while cutting back on antibiotics and antibacterial products.

Except that...

The gym might be one place where these products are justified. I still think the woman I described in the first paragraph was overdoing it, performing the equivalent of cleaning up an overturned glass of juice with a Clorox wipe or spritz of Lysol. But considering the risks, it does make sense to disinfect certain parts of certain machines, and to be especially thorough if you know you are carrying some sort of pathogen.

1. www.menshealth.com/sweat/practice-proper-sweatiquette.php

2. Ibid.

3. http://thechart.blogs.cnn.com/2011/06/24/what-the-yuck-gym-machine-germs/

4. www.nytimes.com/2010/08/03/health/03brod.html?_r=0

5. www.bbc.co.uk/worldservice/sci_tech/highlights/011115_sweat.shtml

6. www.menshealth.com/sweat/practice-proper-sweatiquette.php

7. abclocal.go.com/kabc/story?section=news/health/your_health&id=8999101

The Bloodflow Hypothesis Rabbit Hole

A few weeks ago I injured myself while lifting weights—while putting them down, to be exact. The incident, though a bothersome interruption to my workout, served both as a reminder to observe good safety practices at the gym and as an opportunity to expand my knowledge about science, a loose goal I set back in July.

I was doing shoulder presses with 25-lb. weights, and I wasn’t very careful in replacing them in the weight rack. Instead of placing them properly, I managed to crush my fingers between the weights and the metal ridge of the rack. Within seconds blood started to stream out of my left and right ring fingers, so I headed to the front desk for some first aid.

As I sat there waiting for the desk attendant to put his gloves on, I watched the blood begin to roll down my hands. The cuts didn’t hurt much at all, so my thoughts freely drifted. Looking at the unexpectedly large amount of blood (it wasn’t a great deal more than expected, but enough to be noticeable), I began to wonder if the fact that I was lifting weights right before cutting myself—using hand and finger strength to grip the dumbbells—was making me bleed more than I normally would. Though I simultaneously felt like an idiot for being so careless, this hypothesis made me feel a little proud. I’m not very scientifically curious, as a rule, so it was nice to catch myself theorizing without being prompted by someone else. I decided to check into the increased bloodflow idea later that day.

Later that day turned into a few weeks later. Either I wasn’t that curious, or other matters took priority—probably both. Nevertheless, I finally began searching the internet for information, soon finding some answers from sources that appear credible:

"Blood flow through tissues is matched with the metabolic needs of the tissues. During exercise, blood flow through tissues is changed dramatically. Its rate of flow through exercising skeletal muscles can be 15 to 20 times greater than through resting muscles."¹

^{Image by Chris Aldridge.}

As science writer Craig Freudenrich explains,

"As you exercise, the blood vessels in your muscles dilate and the blood flow is greater, just as more water flows through a fire hose than through a garden hose. . . . As [the chemical compound] ATP gets used up in working muscle, the muscle produces several metabolic byproducts. . . These byproducts leave the muscle cells and cause the capillaries. . . within the muscle to expand or dilate. The increased blood flow delivers more oxygenated blood to the working muscle."²

Next I decided to learn a bit more about specific muscles in the hand and fingers, but I quickly discovered that in fact there are no muscles in the fingers.³ When I first read this I wondered if it might be one of the many “crazy facts” lurking on the internet that are just crazy, not factual. Further investigation, however, confirmed that the muscles that help move the fingers are located on the hand and forearm.

This makes me doubt my original hypothesis, because I was bleeding from the fingers. It was the lower part of the finger, so it makes sense that increased bloodflow to my hand muscles resulted in abnormally high bleeding nearby. But for all I know, what seems like proximity to me is actually remoteness on the level of capillaries, and the increased bleeding was simply illusory. Or caused by something else entirely.

What other factors cause bloodflow to increase? Do any other body parts besides fingers operate in a remote control-like way? I use the phrase “rabbit hole” in this post’s title because one empirical observation can create a never-ending chain of questions. I like that. The humanities scholar Barbara Herrnstein Smith (who at first studied chemistry in college, actually) has written about literature, “The completed work is thus always, in a sense, a temporary truce among contending forces, achieved at the point of exhaustion...”⁴ With scientific inquiry, too, one eventually has to stop somewhere, at least for the moment.

This can be frustrating when the desire to know, to understand, persists beyond our energies. But the idea that there’s always another question to be asked is bracing. None of us will ever reach the final answer of any line of inquiry. There will always be another question. And because we’re human, we’ll always make mistakes—like smashing our fingers with dumbbells—that set off the whole process.

1. Rod Seeley, Trent Stephens, and Philip Tate, “Blood Flow Through Tissues During Exercise,” Anatomy and Physiology, 5^th ed., McGraw-Hill, accessed April 27 2013, http://www.mhhe.com/biosci/ap/seeleyap/cardio/reading4.mhtml.

2. Craig Freudenrich, “How Exercise Works,” Discovery Fit & Health, accessed April 27, 2013, http://health.howstuffworks.com/wellness/diet-fitness/exercise/sports-physiology8.htm.

3. Apart from the tiny muscles that form goosebumps.

4. Barbara Herrnstein Smith, “Contingencies of Value,” The Norton Anthology of Theory and Criticism, 2^nd ed, ed. Vincent B. Leitch (New York: Norton, 2010), 1810.

 

The Science of Decline Sit-ups

As I am a moderately well-read person, my poor understanding of science is a source of embarrassment. It’s possible I know as much science as the average American. Still, I haven’t studied it as much as I would like, nor does my brain seem particularly well-suited for it. I’m good with words and pretty good with numbers, but thinking spatially or mechanically is a challenge.

Because I spend a lot of time in the gym, I have decided to improve my understanding of certain scientific principles by studying different exercises and equipment. My hope is that in actually using my own body to do various movements, the principles will sink in better than they have before.

Shortly after choosing decline sit-ups for my first investigation, I explained my plan to a science-minded friend. “What forces do you think are involved?” he asked. “Fulcrums, levers, gravity?” I hazarded. “And torque,” he replied. Torque. The word calls to mind cars.

My next step was some online searches. The Wikipedia “Torque” entry was potentially informative. On one site, I found the following: “However, to avoid a lesson in physics we can summate the concept [of arm placement during decline sit-ups] as follows.” Not helpful, except that with a quick side investigation I learned that “summate” is a legitimate word, though it sounds off to my ear. Back at Wikipedia, I clicked links on the “Torque” page.

Source: http://en.wikipedia.org/wiki/Torque

I admit I breezed through these and several other websites. Part of the problem is that I am not really all that interested in learning more science. It’s something I think I should do, and I kind of wish I could automatically deposit the knowledge in my brain. Still, perhaps if I can get a few footholds through this gym/science scheme, I’ll begin to find it more interesting.

Eventually I wound up on a website that looks to be quite informative and reputable, ExRx.net. It contains a page about levers, as well as a page on the weighted decline sit-up (and hundreds of other exercises). On the decline sit-up page, I read, “Lower decline to increase resistance.” I then set about to answer the simple question “Why does lowering the decline increase resistance?” If this is the physics equivalent of “Who wrote Adventures of Huckleberry Finn?”, so be it.

My first thought was that gravity might be involved. Something along the lines of slightly more air offering resistance as one is moving up. But that didn’t seem right—that air would only weigh minimally more, wouldn’t it, not enough to produce the effect that I know from experience is more significant. Then I remembered that as distance increases from the point of the fulcrum, or something like that, it requires more effort to move.

Returning to the lever page on ExRx.net, I saw I had the idea right, if not the terminology. What I thought of as the point of the fulcrum is in fact called a fulcrum, while the whole thing is a lever. Decline sit-ups seem to be either second– or third-class levers, the latter only if you hold a weight behind your head. As the page states, a third-class lever “requires relatively great force to move even small resistances.” I was able to empirically verify this statement during my last weight training session, when I held a 10-lb. weight behind my head instead of on my chest like I usually do. It was not easy.

A Third-class Lever

Source: ExRx.net

I have only scratched the surface of levers here, and I haven’t yet figured out what torque is or followed up on whether my gravity instinct has any truth to it. Yet I’ll be damned if I don’t feel a bit more eager to continue learning more science. And as far as I’m concerned, that makes this first inquiry a success.