Does Your Body Have a Set Point For Exercise? [Duelling Research]

Just when you thought it was safe to retrieve the forks and knives you hid during the “Are white potatoes a nutritious natural food or glycemic index hell tuber?” debate, scientists have given us another research study that brings up more questions than it answers.  And this time it’s about your “activitystat”, questioning whether or not humans have an internal set point for activity like it’s commonly thought we do for weight.

Dr. Terence J. Wilkin, a professor of endocrinology at the Peninsula Medical School in Plymouth, England, designed a study to test this out by going to the source of all (hyper)activity in the universe: children. After outfitting the 70 kidlets with accelerometers to measure their activity over the course of four weeks he set them free to run amok as they wished (no word on if ear-tagging was used). The kids were broken down into three groups based on which school they go to – in a sad commentary on the perils of poverty, the private-schoolers had 9.2 hours of P.E. per week, the village-schoolers had 2.2 and the urban-schoolers only got 1.6. The idea was to see how activity levels during the school day affected activity levels outside of school.

The results may surprise you: “When [Dr. Wilkin] collated the data, the weekly activity levels of the students from all three schools were remarkably similar. Students who exercised more at school were less active afterward. In a study published this month in The International Journal of Obesity, Dr. Wilkin and his co-authors conclude that, at least in these 8- to 10-year-olds, ‘activity at one time is met with less activity at another.'” These findings aligned with a similar study performed on adult women in which half of the subjects spontaneously reduced their incidental activity in response to an increase in their workouts. This, of course, has all kinds of ramifications for fitness guidelines.

At first glance these results made intuitive sense to me. Anyone who’s run 20 miles and then come home and begged off going dancing with the girls later that night so they can crash at 8 p.m. in a puddle of their own drool will know what I’m talking about. But the more I thought about this the more it bothered me because while this may be the case for me in isolated incidents when I do something particularly strenuous, it isn’t true for me overall. And because we all know that me and my anecdotal evidence are the most important factor in all scientific research, I have to question Dr. Wilkin and his band of not-so-feisty fifth-graders.

This may shock you: there was a time in my life where I not only did not exercise but I actively avoided it. Really I’m pretty new to this whole fitness scene as I only jumped in – with both feet until I was in over my head and drowning because that’s how I like to do everything – 7 years ago after the birth of my second son. (You can read my how I found fitness story here if you’re curious but be warned that I talk about my sexual assault.) To make a very long story short, I went from being winded carrying the laundry up the stairs to, well, doing what I do now. And over that 7-year span, while I don’t have the accelerometer data to prove it, I greatly increased my activity levels overall. First was because I had to: kids are relentless, if they think you are even considering resting they will immediately get diarrhea or shove a sock down the toilet. Second, though, was because I had so much more energy that I chose to do more.

There is research to support this side as well. Two different twin studies concluded, “While the children’s fidgetiness and enjoyment of activity were dependent on heredity, their actual levels of movement were almost wholly determined by their environment, and in particular by the actions and attitudes of their teachers and parents.” In addition there is the opposite question of what happens to people if you force them to be more sedentary than usual and the research has shown that they usually do not resume their former levels of activity.

My theory, based on minutes of extensive Internet reading and pondering in the bathroom, is that they’re both right. I think that perhaps our bodies do have a set level of activity that makes us feel good and that we gravitate to. But I think that our environment at large can reset our “activitystat” to lower or higher based on what we do. As for the kids in the first study, I’m wondering if the fact they were “forced” to exercise (because it was part of the school curriculum) and so it wasn’t their choice was a factor in choosing whether or not to be active late. Or… maybe not.

What’s your experience – do you have a general level of activity that you gravitate towards? Or do you think that our activity levels are primarily a function of our environment? And just out of curiousity: white potatoes – eat ’em or avoid ’em?? (Please don’t throw a fork at me.)

42 Comments

  1. I have to exercise daily or I am an emotional grumpy mess. And for me, that’s a light run and some light yoga. Long gone are the days of 10 mile runs and 2 hour yoga classes. No way do I have time for all that but for 30-45 mins a day I HAVE to do something. And on days where I don’t do either, it means I genuinely have a need for a rest day OR I have just been on my feet in the kitchen all day on a bakestravganza, been to Target, two grocery stores, and done 4 loads of laundry. I’m sure you know those days 🙂

  2. I find it depends on what I do in a day as to how much rest I need afterwards. Weight training = less done during the day while a 45 minute walk will have me still running around the place as usual.

    As for the good old white potato? Anyone who doesn’t want theirs can feel free to send them in my direction!

    • Interesting point about the type of exercise being an important variable – I think you are right! I imagine intensity has an effect as well. (And I love me a potato too…)

  3. I find that I do more after I workout. I have much more energy after a fun Zumb Session than I do just lounging around all day. If I’m being lazy, then it’s hard to get myself started on anything. If I already am going then I just don’t stop. If I don’t get my workout in you can bet my claws will be showing too. I get fussy when I don’t get to workout.

    Even today, my girls were a needy mess and when the hubs walked in scarfed down dinner then got to work on prep for tomorrow’s cupcake order. I had no time to even switch the laundry and yet I’m wishing I had enough time to work on some choreography. So I think once you get started you tend ot have more energy to keep going. At least I do.

    As to white potatoes. They are like Batman to me if I were Robin. I feel I wouldn’t exist without them.

    • I feel the same way about learning new choreo:) I just want to practice it until I get it whether I’m at home doing dishes or at the grocery store or wherever, lol! And cupcake order?? You must own a bakery…,mmm!

      • I kind of have a bakery. Oregon allows for Domestic Kitchen Lincenses so I can work from home. They have a few rules you have to follow but it’s not so bad. It helps tap into the creative parts of my brain.

  4. Why are you showing this picture of the disabled woman who prefers a Segway over a wheelchair? This picture has nothing to do with fitness. Her story broke out after this pic was shown all over the internet.

  5. I call baloney. (Or bologna, if you’re a traditionalist.) I was a total couch potato before I forced myself to start exercising when I was 45. Over the next several years I gradually increased the time and intensity of my work-outs, and now my activity levels are extremely high.

  6. INTERESTING.
    for me there is a set point of exercise for sure (30 minutes needed or not :)) but I know that’s all a result of my patience level.
    I will happily spend 30
    I slowly transition into RESENTNESSMENT when it clicks to 31.

  7. LOL! I love “based on minutes of internet research and pondering in the bathroom”!!!

    I’ll be honest, before I go to work and after I get home from the gym… I’m on my butt on the couch or at the kitchen table. Sometimes laying in bed. I do a lot of standing/running around looking for things at work (some days it is a sedentary job, but most days it isn’t and I often opt to stand at my work bench rather than sit) and add workouts to that? I simply don’t want to move so maybe there is a set point limit for me.

    On the same token, I, like you, used to LOATHE exercise. Granted, this was when I thought exercise meant only ellipticalling and not making any progress. LOL

    • Yes, I used to think that exercise was either a) running or b) doing 80’s aerobics and I hated both (although I’ve kinda come around on those too, lol). Thank goodness we both figured it out!

  8. The study on the kids seems incomplete to me. It may very well be that the private school kids were less active outside of school because they had more homework or because they had more stagnant activities (think piano lessons) than the others. I’m not sure how you would normalize for that, but it does seem important.

  9. In the past 18 years (OMG that number makes me feel old!) I have gone through many periods of being more and less active. Most of the time it has been towards the more active side, but when I couldn’t afford a gym membership, was too busy studying or just wasn’t into it, I have had times when I have been a couch potato. I found that once I got into a time when I wasn’t exercising, I was quite happy to be more sedentary and while I may have gone for a walk now and then overall I was okay with inactivity.
    When I am exercising regularly though, if for some reason I am not able to for a week or so, I start to feel restless. Really, really restless and I will suddenly get up and do whatever is available to me. Even a weekend at the cottage can have me jogging down the road by Sunday (and I am NOT a jogger!).
    So for me, it all depends on how active I currently am in my life. As the scientists say, things in motion tend to stay in motion, things at rest tend to stay at rest.

    • Yeah I get antsy too if I don’t get some kind of exercise. Love this ” As the scientists say, things in motion tend to stay in motion, things at rest tend to stay at rest.”!

  10. Experience tells me that there is only so much I can do in one day. I’m including all kinds of activity here, not just exercise. Some days I am better at gauging this than others, and I can tell when I overdo it. As far as exercise goes, I don’t think that means I can’t learn new activities and improve my fitness level or strength, but I think it might take me more time to do so. Or else it means I’m going to skipping out on other things.

    I’ve always been this way, I get tired and overwhelmed easily and if I push myself too hard I either turn into a zombie or end up bawling over trivial things. I heard someone describe it once as having ‘low energy’ which seems like a pretty good description. So my experience may not be typical.

  11. I tend to exercise for the same amount of time everyday, so maybe? But its probably all in my head. If I don’t do any exercise, I get antsy and fidgety and CRABBY. I know when I am truly in need of a rest day because I am not crabby, and its 6 pm and I haven’t exercised yet. But I also notice on days with a big workout, that I don’t want to move the rest of the day. I’ll walk to work to avoid my bike.

  12. I eat a baked potato once in a while.

    As for exercise, I have never quantified it. I don’t worry about heart rate, or most any other measurement. I just do it. Maybe I have invented intuitive exercising!

  13. I think that maybe we have multiple set points. When I didn’t exercise I definitely didn’t make up for it by being extra active and I found it hard to increase my activity level. Now that I exercise regularly I feel more energetic and move around much more in general- that being said, when I start increasing my activity level (like training up for a half or full marathon) I am definitely more tired and (obviously) need to eat more.
    My takeway from this is kind of a spin off, but it makes me think about the importance of getting enough sleep so that you can keep up a high level of activity, does that makes sense?

    • It makes total sense. And I think that it’s very telling that one of the first signs of problems with your body (either under-exercising or over-training) is that your sleep gets off…

  14. I wholeheartedly agree that any set point, if it exists, can be changed. (Personally I don’t feel as if I have a set point. I have a whining point, but not a set point.)

    I’ve noticed, too, that sometimes my body will overrule my head. This week, for instance, I’ve have more free time than I normally do. I fully intended to workout on my free days (no, really!) but ended up taking a nap instead. Seeing as I’ve been going all-out, 7 days a week, on about 5 hours of sleep a night, it was probably the right move.
    Go, Body!

    • Yeah our bodies are smart! Good for you for listening! And this: “I have a whining point, but not a set point.” cracks me up. Me too, sister.

  15. The more active I am in the morning, the more active I am all day. The energy I get is fantastic! I don’t think when I’m done grad school I ‘ll be able to “slow down”…I’ll just rekindle a lot of awesome hobbies 🙂
    And I love me some white potatoes. I like them riced…yumm…

  16. For me it all depends on what I ate during the day. I find that if I have too much sugar, bread/pasta, heavy foods, etc. I will fidget and move around like crazy, especially if I don’t workout. If I stick to my usual: vegetables, lean meats, etc. then I don’t feel the need to move around like a madwoman. Something interesting worth noting is that before I worked out regularly, if I ate heavy foods I would feel lethargic. Interesting.

    P.S. I love your blog!

    • Thank you! And very interesting about your personal observations of how your food affects your energy levels. I find that if I eat a lot of sugar it makes me antsy for a little bit but then I crash hard and am sooo tired.

  17. The more activity I do the more active I continue to be, unless, like you, I’ve absolutely pushed it too far and then all I can do is be a zombie on the couch. On days when I am less active, I have less energy and stay less active. Those are my scientific results! A body in motion . . .

  18. When I was in the prime of my ED I avoided exercise too. I wanted my bones to show not muscle to cover them.

    Now I am most active durning the morning when my disabled arm is at it’s least amount of pain. I normally do my hour to hour and a half workout around 10am then do any chores needing done. But after 1pm I don’t do much physically. I’m in too much pain.

    • This is unrelated but I think that chronic pain can be one of the most difficult things someone can deal with and I truly admire how well you deal with and work around your arm!

      • Ya it’s hard, somedays are clock days, where I just watch the clock as to how soon I can take my next pain meds. But I have Sam that I have to some what function for. So I do what needs to be done!

        Side note girl checkout my latest header I did yesterday (art helps keep my mind off the pain too!)
        http://www.theboldblend.com/

  19. I remember reading about one of these accelerometer studies where they had issues with the data because the kids thought it would be funny to put the devices on their dogs so it looked like they were active while they were watching TV. LOL

    My relationship with exercise is still pathological enough that my experiences with activitystats are probably outside the norm. I DO notice more spontaneous moving around and displays of energy when I’m in periods of eating well and keeping exercise in check, but I would be floored if those actually equalled the amount of energy I was previously expending at the gym in a given day. It’s hard to say, though, because metabolism flux means nothing is ever a simple numbers game, calorie expenditure can vary pretty significantly even if your weight doesn’t change.

    Potatoes: I will eat white with no guilt whatsoever (they do actually have a lot of nutrients) but choose sweet potatoes if given the choice, just because I prefer the taste.

  20. The exercise I’ve done over the years has varied massively, from none as a teenager in sixth form finally allowed to give up school sports to getting in my 10,000 steps a day and then some. Even now I can have incredibly lazy days and incredibly active days. I suppose most days are somewhere in between.

    I do find I have a sort of base level of exercise – I get lethargic and headachy if I don’t get any fresh air combined with a brisk walk for more than two days in a row.

  21. Hmmm, I just wonder about the studies on the kids. We just finished soccer season and I have 10 girls complaining about how tired they are when practice is over, but after a 5 minute break they (those who are still waiting for parents to pick them up) are jumping around doing cartwheels and playing chase.

    I think the biggest problem is how often we tell our kids “no, stop playing, not now”. In our society there isn’t a lot of opportunities for kids to be active (sit in the car, sit in school, sit in the restaurant, walk-don’t run in the store, don’t jump on the furniture in the house…well maybe ignore that one at my house), we tell them “don’t move around” a lot more than we say “go run, jump and play”.

    • This: “we tell them “don’t move around” a lot more than we say “go run, jump and play”.” is so so true. And I’d say that adults have the same problem too… we’re a sitting society

  22. While I’m sure that there have been times in my life when I’ve been mostly sedentary, in general I’m kinda hyper, and won’t sleep or feel sane if I don’t get in at least an hour’s bike ride daily, if not a gym day. Every few weeks, I’ll take a day off, and just get a walk in. I can’t sit still or focus if I don’t. I think part of it is genetic, I come from a family of exercisers, but I think some is training. My neighbor commutes 1.5 hours each way, is way too tired to exercise, but stress, especially driving stress, makes me want to exercise more, and I think that’s training.

    White potatoes: eat them, usually roasted. Not deep fried. They make a good portable and convenient lunch, fill me up, though I get hungry again quick, even if I add in protein.

    I got a free pedometer the other day, and been tracking a bit, though I have to take it off while seated because it’ll pick up my squirming and shifting, but between walking downstairs for coffee/lunch/breaks, walking here and there to find stuff, check stuff, etc., I’ve hit 100000 steps just by the end of the work day. Seems I should be thinnner than I am.

  23. MOAR POTATOES.

    MOAAAARRRR.

    My activity level is fairly high–
    I tend to give myself “stair breaks” at work;
    every couple of hours or so I dash out the door and run up and down four flights of stairs.
    Because sitting?
    You know, with the death and the unhealthyness?

    I do like to rest almost completely on Sundays, though.
    It’s just a nice reset button after a week of stairs, hour long walks, handbalancing class, competitive salsa, tango, Crossfit + Tabata, and acro-training.

    I think I earn taking Sunday off. 🙂