The Mysterious Interior World of Exercise

What happens inside our bodies when we work out.

Comments: 129

  1. Turns out, our ancestors did not need a gym, the entire planet was their gym. They explored walked swam hunted, to the far corners of the earth. They inhabited settled domesticated animals farmed. Lot of hard physical work which they did happily. These days the youth is missing it all. Instead of actually foraging ingredients and cooking a fresh meal, they order take out. Instead of walking to meet their non virtual friends, they uber or lyft a ride. Instead of figuring out how to mow the lawn or plow snow, they outsource to landscapers. Instead of gardening and tending flowers they hire undocumented laborers and house cleaners. They just don't know how to use their hands and fingers, legs and toes except in the gym where they can beautifully sculpt their bodies to look like their ancestors who worked so hard to get real work done while maintaining their figure and cholesterol levels. (sorry)

  2. I tried to forage my lunch in the west 20s today. Did not work out well.

  3. Au contraire! Their thumb muscles are exceedingly well developed thanks to texting!

  4. I think you're making a lot of assumptions when you say our ancestors did all that hard work happily. Maybe they did and maybe they didn't, but they did it because they had to to survive. And, if they loved all the hard, physical work, I'm pretty sure mankind would not have invented all the time and labor-saving tools.

  5. Considering the time to vesicle distribution and dissolution can be in the tens of minutes, I fail to see the connection to real-time benefits during exercise as the writer has suggested. There may be benefits derived afterward. Any actual experts out there? Anyone read the quoted paper from behind the paywall?

  6. The myokines contribute to long term adaptations to your physiolgy, eg more availability of physical energy in general. It's a fascinating new field. There are hundreds of myokines released during physical activity that affect every aspect of physiology. This study identified 35 potential new ones alone. Researchers speculate they are responsible for many of the long-term benefits of exercise, including longevity and brain health. Not a lot of "knowns" yet though.

  7. Why these insults to this interesting article? And yes, I pay for the NYT and the Washington Post and the WSJ and even other truth tellers we need more than ever now.

  8. The obviouis guess would be glycogen utilization. Your muscles already have their own store that will last a little while, but the liver has a much larger one. Letting the liver know that its own stores might be necessary in the near future seems like a useful function for a relatively slow signalling pathway.

  9. Photo choice weird, as usual. Studies involved only mice and men, also as usual.

  10. You think this story didn't require a picture of young adults with a female in the foreground?

  11. No offense intended, your point is well taken, however.. Steinbeck ? Had to chuckle.

  12. I just want to know where 'that' gym is.

  13. "Leg Muscle here, apparently we're going to run." "No body ever tells me anything!" - Brain "Liver here, preparing for enzymes now." "Hurry it up for God's sake, he's doing intervals!!"

  14. This is my life.

  15. One of the things I most love about yoga is the extent to which you can really feel all the body's systems communicating with one another. The mind-quieting aspect of the practice creates an ideal situation for detecting and listening to this inter-system communication. I realize this sounds pretty woo, but once you experience it, it's unmistakable, and downright revelatory.

  16. The best part about yoga is that you do NOT need to wear yoga gear commercialized by marketers. Yoga in its simplest form can be done anywhere, at any temperature in loosely fitting cotton clothes. I know a grandma in her 70s who did yoga exercises in her sari. In the US, yoga studios and associates make money just because their customers can pay for simple or complex exercises that really do not need a fancy room, mat or lululemon $$ brand yoga gear.

  17. Yoga is not exercise. It's stretching, or relaxation but it's most definitely not exercise!

  18. the best part of yoga is zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz.

  19. It will be interesting to see if / how vesicle release can impact or cause the Central Governor Theory of fatigue.

  20. Just a matter of time until big pharma develops vesicle technology in pill form, so us lazy Americans can get the benefits of exercise without any effort!

  21. If pill form could also promote a better wellness for those who are in wheelchairs or have limited mobility to get "exercise" and have a better quality of life or get well again.

  22. Assume you're joking...big pharma keeps stealing from nature and in its limited capacity for understanding the bigger dynamics, keeps missing the mark of what is true health. I'm going to make another assumption that if they attempt this, they'd make the same mistakes.

  23. As an avid exerciser, I find this truly interesting. Next time I'm churning through my swim, I'll think of little bike messengers on their way to my liver saying "Get up, she's moving" and my liver responding "For the love of everything that is green, it's 5am, I'm asleep!"

  24. At 6:15 this morning I was swimming in our suburban, community pool. I don't swim far or fast but my body and mind always works better after this exercise. I'm a 66 y/o male and I'm at same weight as when I graduated HS in 1969. I didn't relish the thought of going out in the cold or dark and on icy streets this morning but it was worth it. I swim 3-4 times a week.

  25. Whenever feeling unenthused about hitting the pool, I've said to myself "I won't regret it after Its done". Knowing a good feeling follows a workout has helped overcome many exercise-avoiance excuses.

  26. I, too, swim laps and decided decades ago that if I let New England weather dictate my exercise routine, I'd be stuck at home for several months every year. Swimming keeps me limber and upbeat at age 73.

  27. I'm becoming inspired by all these comments about swimming; thank you all.

  28. Just wondering if this research could be applied to the study of ME/CFS.
    What if the liver doesn't make more energy?

  29. I loved the image of the body’s internal organs being “as gossipy and socially entangled as any 8th grade classroom,” and everybody wanting “to be buddies with the liver.” I may never think about my “innards” the same way again.

  30. For me, it immediately brings to mind a film we were shown in 6th grade science class oh so many years ago. The film imagined the human body populated with workers - inside the brain workers, operated the controls and made decisions, in the heart, workers shoveled coal into the furnace to create more energy during exercise, other workers controlled the digestive processes, and so on. The one line that I will never forget is, when exercise stopped and thus the need to keep the heart's furnace roaring came to an end, the foreman told his crew to "Take a break, men; smoke 'em if you got 'em!"

  31. Yes. Kudos to Gretchen for exceptionally good writing.

  32. I would check out and you will find out that the qiqong masters discovered this centuries ago. In fact, I do a qiqong practice called the 5 element flow that focuses on the lungs, kidneys, liver, heart and spleen and their holistic interconnection.

  33. So, as a runner, is it apt for me to say, I'm going out to manufacture Vesicles?

  34. Or opt out of corporate life and get a job that runs you around a bit.You wont make as much money, but you will be in better shape.

  35. My track workouts are pretty consistent. My roadwork varies wildly. I guess my cells are orderly when I go round and round but are chaotic when they don’t know what to expect. I need a liver with more discipline.

  36. Much of what is known about the effects of exercise has been known since the 1920s when the Harvard Exercise Fatigue Lab conducted many experiments to understand the biological significance of homeostasis. The lab's chief exercise subject was the marathon runner, Clarence DeMar, who won the won the race 7 times from 1919 to 1929. The Fatigue Lab's studies provided the basis of understanding for the benefits of physical exercise, distinguishing the fit from the unfit, and disease brought on by physical inactivity. What distinguishes that era from now is the narcissistic pursuit of exercise that has developed since the 1970s, which Christopher Lasch brilliantly described in the Culture of Narcissism. Written 1978, the book is as relevant now as then. The image accompanying this article demonstrates Lasch's thesis. Exercise for the sake of exercise.

  37. "carrying pressing biochemical messages" is one of those messages a smug sense of superiority over others?

  38. Another article from Gretchen based on articles written by others with few facts and fewer conclusions.

  39. This makes a lot of sense based on the timing of energy when you work out. I've always wondered why the warm up we do in exercise class I've been doing for many years was so hard and the much harder work out that followed was comparatively easier. This might suggest a little longer warm up, even if it's just walking.

  40. I don’t understand two aspects of this study. First, what take samples from a huge artery, the femoral, which is the vessel going TO the exercising muscles while biking? Wouldn’t a safer venous sample be fine? Second, the vehicle products are taken up by the liver. Why doesn’t this just mean the liver is doing it’s job of trash removal instead of being a “signal?”

  41. They may have been monitoring arterial blood oxygen levels.

  42. my energy levels picked up with the photo. no need for exercise. NYT please stop with click bait. I am not paying for click bait.

  43. Nice article. I will not be sharing this article on my fitness studio feed on FB or in my newsletter to my clients because of the photo choice. About 6 reasons why. Bad choice.

  44. This photo displays some of the reasons I don't go to public gyms anymore. The sweat pouring off of so many is gross, smells really awful too. In the past I've been showered with the perspiration of others while on a neighboring machine. The younger buff dudes don't seem to care. This and I hate either the loud, banging music or walls covered with tv screens, polluting everywhere one gazes. Why do the gyms have to be so obnoxious? Turn it down and off. Unplug.

  45. FYI - Planet Fitness does not permit bare chests, bare midriffs, or even "muscle" shirts. And, I wear snug-fitting earbuds so I can listen to my own music - on most days, that means Italian pop music - Il Volo, Nek, Biagio Antonacci, Laura Pausini, Patrizio Buanne...

  46. I have just bought the new wireless Sennheiser over the ear noise cancelling headphones. Easy Bluetooth connection to phone play list. Makes a workout very private. A bit pricey but well worth it.

  47. One of the best exercises is walking, no need for a gym. Our ancestors walked everywhere. Plus the benefits of fresh air and a chance to experience the changing seasons

  48. Also, write about what happens when we -don't- work out. The corrosion and stagnation of the body and the spirit.

  49. I was on the stationary bike peddling furiously for 75 minutes. No vesicles, just tired. And I participated in a university study measuring the cognitive effects of heavy exercise. My aerobic capacity vastly improved. But I got stupider. Wish I could say I was joking. I continue to work out hard everyday for more than an hour. You don't need a brain but you do need a heart. Then again maybe you don't need that either. Just look at our president.

  50. And about that photo: No shorts, no shirts, no sweating!

  51. There will never be a pill that gives you the same benefit as a workout. Exercise makes everything better. Sure, it would be wonderful not to have to devote the time or energy to actually working out, but the benefits are quite extraordinary. Keeping oneself in peak condition, or better condition than mere couch surfing, is as important as eating or sleeping, in my very humble opinion. And, as you age, it becomes even more important. This is still the best advice available to all: eat foods without additives, too much salt or sugar, consume lots of fruits and veggies, drink enough fluids, get plenty of sleep and by all means, get your body moving through any form of exercise you choose. It is a commitment to yourself and it makes life better.

  52. clickbait photo got me.

  53. I was expecting an article on mental states, but this was fascinating in its own right.

  54. Brazilian/Canadian scientists previously did a very similar study for the post-exercise response and it is as mysterious, if not more so, as the peri-exercise response. It turns out that any exercise does an incredible damage at cellular level and the body whips up a series of immune reaction for several days to clean up the debris and repair the damage. Even taking a few steps does enough damage to induce the immune response. Healthy people wouldn't feel anything of course, but people with CFS, also known as Systemic Exercise Intolerance Disease, could keel over till the post-exercise response is over.

  55. I wonder if there was a scientific reason to run the test on just men? Why not use a sample of both men and women?

  56. Women should be tested. But I imagine that testing only men did simplify the analysis. Men and women do metabolize fat differently and also respond to exercise differently. But everyone has a liver. I think it's safe to assume that women also have "a huge amount of complexity in the circulating blood during exercise", but it would be fascinating--and could be important medically--to know whether and how women differ from men. Apart from medical implications, athletics--for both men and women--may provide a motivation to lear more sooner rather than later.

  57. Just as every new technical breakthrough soon finds a porn application, this metabolic breakthrough will surely find a doping one.

  58. We're only as good as our telomeres, right? This is great research, and I'd like to see more... specifically, how is a person's hydration level a factor in the movement of vesicles throughout the body. The largest component of the human body is water. Do vesicles move better in a well-hydrated human? One would think so. Is this the science behind why water and being well hydrated is so key to overall exercise and daily performance? I've been doing intermittent fasting for 2 years now, skipping breakfast. I work out in the AM, and also drink the majority of my water (1/2 gallon) in the morning and early afternoon. Sounds like I may have stumbled onto an optimal timing regimen to get those vesicles moved to the liver in order to process a secondary energy source (body fat). Full steam ahead!

  59. The man on the left looks like he’s judging me.

  60. what happens to our bodies---they get VERY TIRED. Mine goes to sleep if I even THINK of exercise This is the biggest con job in American history. The body is still growing for people entering their 20's but the MIND? that's aready dead mostly. If people spent the time on LEARNING something like a new language --Chinese anyone--the USA would be far ahead of any country in the world. As it is, we are lower than some African "s-hole "nations. someday, someone will write the expose of the "sports culture" of the USA and will be a real winner. I see people walking or running at the beach--WITH A CELL PHONE IN HAND. can;t even stop for ten seconds. The rich get richer, the dumb get dumber.

  61. Exercise and reading are not mutually exclusive.

  62. Okay. It’s really messed up. It’s like, your fat cells like you, but like, they don’t *like* like you.

  63. Very nice but what does it mean?

  64. With the photo and headline, I thought this article was going to be about the 'mysterious interior world' of a Soul Cycle studio.

  65. If the study included only men (and I wonder if they were all of the same ethnicity), why does the article writer use "we"? Unless Gretchen Reynolds is a man, the article author does not know whether she is included in that we. It can very possibly be that women have different vesicles. So now we will spend years of women following advice based only on men, until it occurs to someone years down the road to do the same experiment on women.

  66. the story get better.

  67. Gyms are the worst exercise places. The body doesn't like the noise, smell, bragging, and flirting of others around you. The body wants to be left alone, be in the woods, smell real nature, and reacts to unplanned random physical challenges.

  68. Says the guy from New York.

  69. It's pretty quite in my gym, it's not smelly. No bragging, no flirting - if anything the humor is self deprecating. You might try a new gym.

  70. Point well made, but I would still recommend a run with a dog in a forest if you have access to dog and forest.

  71. You mean I no longer have to specifically tell my liver that we're going running, like I have for years, it somehow already knows? Too bad, those little chats have really brought us close together over time. I feel like I'm losing a friend after reading this.

  72. John, not to worry. Like the stock market, you don't actually lose until you cash out.

  73. Stay fit, keep your head in your phone, and get hit.

  74. My first reaction is that I would not want anyone putting a hole in my femoral artery.

  75. They did that to me for my two stents. I'm still delighted with the results!

  76. Some corrections from the top: "When we exercise, far-flung parts of us apparently communicate...." "For some time, scientists have suspected that our internal organs are as gossipy...." Argh! Dissociation and abstraction are two of my least favourite things. Imagine if they caused cancer! Their ought to be consequences for bad thinking and bad expression. No-one has a body. There is no such thing as "the body". All are human beings. All are individuals. Sigh.

  77. I found this article fascinating. I just resumed an exercise routine at a local gym. All body parts are feeling better, not just the ones being worked. The findings help explain the effects of warm ups, intervals and the many endocrine and other benefits of exercise I hope to see more information on this.

  78. " Inserting tubes into the thighs of 11 healthy men and drawing blood from their femoral arteries." Those men must have been very, very brave! I wouldn't let a Doctor, let alone a medical researcher, do procedures like that, if I was healthy! Flirting with possible disaster, is what those guinea pigs were doing!

  79. While, yes, those men were brave (or foolish), and here is yet another study that only takes MEN as its subject. So we now know that this is how MEN's bodies behave. Maybe it's how women's bodies behave, too, but let's stop pretending that this study has any claim to representing both genders' response to exercise.

  80. Counter, you have a good point but, hey, women already outlive us men by a decade or so, so please give us a chance to try to catch up!

  81. Humans were only the beginning of the study. The studies on mice provided the most data and presumably were of both sexes. You can be sure there will be more work done on this.

  82. "the fundamental message of the findings is that our bodies contain a different interior world when we move than when we do not."

    Wow - I only knew I felt better for hours after exercise - never thought my BODY or it's INTERIOR had anything to do with it!

    Thank God for scientific journalism discovering this for me!

  83. The original publication is behind a paywall; all I could read for free was the abstract. That's too bad, because I would have liked to be able to read parts of it.

  84. Most newspapers are not given away for free. It is very expensive to provide quality content. Buy a copy of the issue or go to the library to read for free.

  85. "In essence, the scientists had found that exercise prompts the creation of vesicles that somehow know to head for the liver and tell it to ramp up energy production." I can't say about the study, but this article is gross pseudoscience! All of our blood passes through our livers on the way back to our hearts. Those vesicles don't have to 'somehow know' anything at all. Sadly, this interpretation gave me a very negative opinion of the author.

  86. Joschka, It's all (or most) of our blood from the small intestine, part of the colon, and spleen that passes, first, through the liver (the hepatic portal circulation), before returning to the heart. That's an important distinction to make regarding the origin and "destination" of those vesicles, since those coming from exercising skeletal muscle would NOT pass first through the liver and might reach other "target" organs before ever having the chance to enter the hepatic circulation. Given the constant right ventricular mixing of all blood returning to the heart, invariably, all "unclaimed" vesicles will have the chance to reach the liver, but in a much-"diluted" fashion. The hepatic portal system is especially important in the processing of our digested and absorbed food, since most of such food absorption occurs during passage through the first part of the small intestine, from where digested particles will be hustled off to the liver.

  87. Joschka, I'm a blindness researcher in a medical school and fear you missed a point. Yes, ultimately all blood is filtered by the liver, but the article says the vesicles "made a beeline" for the liver. That's physically possible because not all blood naturally follows the most direct path to the liver. For example, any blood that flows to the kidneys bypasses the liver. That's clear from this simple blood flow circuit diagram: I don't have time to read the original article, but you could if you still believe Gretchen did not accurately represent the original work.

  88. Plus, its not only that the vesicles made a beeline to the liver, but what they did when they got there. "vesicles exterior walls dissolved, protein messages absorbed.." Liver was targeted by payload and receptive to it.

  89. This is a great article and pursuit of critical science ranging from seeking answers from chronic pain to obesity to disease prevention. Following sarcastic comments unfortunately only confirm a frightening satisfaction to stagnancy: of mind as well as body.

  90. Not sure I underst.....

  91. @Ray - LOL

  92. I have found that the best part of my favorite exercise, lifting weights, is resting between sets. Sometimes I rest between sets for two or three years.

  93. @Brendan Varley :-) Great comment!! :-) I go to the gym, but I hate lifting weights! Running I love, weights........... Yeah, a 2 or 3 year rest between sets sounds great, but, I would not like the results, so.......... To the gym I go!

  94. Not shocking but nice to know this research has been done. Having run for over twenty years, and enjoying both Pilates and Yoga, I can vouch for the body’s feeling better during and after moving.

  95. Exercise good. Trump bad. Got it?

  96. Lol Brendan!

  97. I know! I know! But we need people like Brendon to keep it all in perspective! A good guy.

  98. Where’s the studies involving exercising WOMEN?

  99. They used both male and female mice.

  100. They were busy tweeting.

  101. EXACTLY what I was thinking. Women are definitely physiologically different than men. They MAY have found that increased exercise gives the vesicles in women super powers that ensure world domination. Now we’ll never know.

  102. Gretchen Reynolds is a great writer! I so enjoyed reading this!

  103. aha! that explains the surge of energy this 86-year-old experiences after her daily 17-mile indoor cycling routine. also, by the way, small aches in her back that previously annoyed her are gone, and she can straighten up as she walks. a fascinating article!

  104. But apparently the mental faculties are diminishing ....

  105. aha! that explains the surge of energy this 86-year-old experiences after her daily 17-mile indoor cycling routine. also, by the way, small aches in her back that previously annoyed her are gone, and she can straighten up as she walks. a fascinating article!

  106. You rock!

  107. Awesome. Hope to be there too at 86!!

  108. Wow--17 miles. How long have you been doing this? I am so impressed--and inspired. As someone else wrote, you rock! I get a surge after 40 minutes of swimming or biking--I will try to push harder and see what happens!

  109. Groundbreaking research confirming in humans a major mechanism of paracrine and endocrine signaling. This will hopefully lead to a significantly better understanding of both physiology and pathology. Congratulations to all involved!

  110. Not only the bodily interior, but quantum forces of space-time are affected. That explains why the clock and mileage on the treadmill stop counting when you look away. Same for stationary bikes. It's like the twins paradox.

  111. With all that jabbing and bloodletting that could on its own cause its own set of reactions, I hope that they had control subjects.

  112. The qiqong masters figured this out centuries ago. While western exercise focuses on muscle and cardiovascular system - Qiqong is holistic and see the interconnection of the body as a whole. I would suggest checking out LEE HOLDEN at He is a great interpreter of qiqong to the west.

  113. I think that I confidently can say that they probably didn't figure this out centuries ago as fluorescent markers are a relatively recent phenomenon as are sampling proteins and vesicles.

  114. Does anyone believe these "studies"?? Figures Don't ie But Liars Do Figure. 50 years of diet and exercise is why 50% are obese and another 20% getting there. So 70% have "benefited?"

  115. Most people are not eating a healthy diet and exercising multiple times per week at a cardio level. Increased sugar consumption, processed foods, lack of veggies and fruits - that’s the American diet. That’s why there’s rampant obesity.

  116. We know that people with chronic fatigue get sick after exercise. Could this somehow be connected? Could a chronic enterovirus or other herpesvirus be sending a "trojan horse" to the liver in these vesicles?

  117. Or could the vesicles contain an epigenetic signal plus or minus for the organism.

  118. More people have "chronic fatigue" because enablers have promoted it as a victim state you can work past doctors than have it legitimately.

  119. As a cyclist, I am tired of studies dependent on running rats. They need more studies where the rats ride bikes.

  120. Wait! Hold on! The body is an integrated system that needs to be maintained? Next you’ll say eating veggies instead of prepackaged, vegetable-flavored, processed food and drinking water instead of “drinks” will sustain that system better. Oh nyt! What will you come up with next?

  121. Those engaged in such prolonged vigorous activities will die healthy.

  122. ...and considerably later in life and with fewer chronic, debilitating, and painful conditions than those sitting on their couch watching TV.

  123. That's certainly my goal, Bob.

  124. I’m sorry. Where’s the gain of function experiment here? Inject collected exercise-induced vesicles from mice at relevant concentrations into the blood stream of non-exercised mice to see if the former had a physiological effect on the latter (not just that they homed to the liver)??? I guess that’s why the paper was in Cell Metabolism and not in Cell

  125. Would love to see this experiment run on women, too.

  126. It seems to me they just found a new way of dopping. Next Olympics they should screen for vesicles.

  127. The day you publish studies that have been replicated is the day when I'll start to take them seriously. Until then it's all speculation.

  128. With Diabetes 2 as the cause for macular edema and hypercholestemia the cause for lipids in the eye?? -- post knee replacement back to at least 30 min of brisk walking daily -- and voila -- less macular edema and lipids disperesed so vision is better. YUP. Exercise is impt. for maintaining a more or less constant and somewhat lower blood sugar level.. Before the knees were done by necessity I was sedentary..

  129. Interesting article, but the one line that will stick with me is, "everybody seems to want to be buddies with the liver." So true.