How Long Does It Take for Fitness Benefits to Show?

Inline_How_Long_Does_It_Take_for_Fitness_Benefits_to_ShowA big reason most people never stick to a serious exercise routine is that the benefits most people are interested in take a while to appear. Fat loss, muscle gain, boosts to strength, speed, and stamina—these physical manifestations of training adherence can take weeks and even months to show. That’s plenty of time for folks to give up, convinced exercise is just not for them.

I get it. I do. But that’s not a valid excuse for not exercising. You know it’s important, you know what the benefits are, and I’m not going to sugarcoat things: training is not optional.

So while we can’t really change when the benefits appear, we can change our expectations of the benefits, making them more realistic and limiting our disappointment when they fail to show in our preferred timing.

So when can we expect some benefits from our hard work?

Some benefits “show” immediately as long as you have the right tools to test them. If you were to take a muscle biopsy, you’d see that muscle protein synthesis—the incorporation of protein into muscle fibers, the first signs of muscular hypertrophy—begins just four hours after you lift something heavy

If you were to sample some bone marrow after a single bout of resistance training, you’d notice that you just upregulated production of the cells that heal your endothelial lining.

If you were to hold a stethoscope up to your hamstrings immediately after a sprint session, you’d hear the *pop-pop-pop* of new mitochondria being spawned.

But those aren’t visible to the naked eye, nor are they accessible to the masses. We don’t feel our bone marrow pumping out progenitor cells. Amazon doesn’t sell muscle biopsy kits.

What benefits can we expect (and notice) immediately?

Fat oxidation: Many types of execise will boost the amount of fat you burn over the course of a day. Sprinting, high-intensity intervals, and even doing moderate aerobic activity before breakfast all increase 24-hour fat oxidation.

Insulin sensitivity: A single bout of intense exercise—lifting, running, sprinting, CrossFit—will deplete glycogen and improve your insulin sensitivity. You can’t “feel” that, but you will notice the improved postprandial blood sugar, as well as the ability to consume more carbohydrates without gaining weight the next day.

Endorphins: One immediate benefit is the release of endogenous opioids, also known as beta-endorphins. Studies indicate that it takes about an hour of endurance training for beta-endorphins to release (the runner’s high), while short-term anaerobic training produces similar effects in even less time. One study found that an acute bout of low-volume, high-intensity Olympic weightlifting caused elevations in beta-endorphin. High-intensity anaerobic work produces the biggest endorphin rush for your buck.

Neural strength: Improvements to neuromuscular efficiency happen within days of starting a lifting program. Beginners get stronger almost immediately simply by learning proper technique and how to fully contract the muscle fibers they already have.

Mood: Acute exercise boosts mood immediately after training, even in patients with major depressive disorder.

Sleep: Exercising in the day has a modest but beneficial effect on sleep that night.

Cognitive function: A single bout of high-intensity interval training boosts cognitive performance and brain-derived neurotrophic factor.

Gene expression: A single bout of endurance training also triggers gene expression in both exercising and non-exercising muscles, upregulating the genes responsible for fat oxidation and metabolism.

What benefits can we see later?

Improved body composition: Thanks to improved insulin sensitivity, better glycogen storage (and depletion), increased fat oxidation, and preservation of lean mass, you should start seeing or feeling the first hints of real positive developments in your body composition after about a week. Remember: whether you’re sprinting, lifting, jogging, or all three, exercise is most effective at improving body composition when paired with healthy eating.

Hypertrophy—actual increases in muscle size—needs a few weeks to get moving. It actually takes longer to develop size than strength, though not as long as you might think.

In one study, training the forearms to failure 3 times a week led to a 0.1 cm increase in forearm thickness at 2 weeks and another 0.1 after 4 weeks.

Another study had subjects do leg extensions for 12 weeks. They got stronger and grew muscle up through the first 8 weeks, but the last four weeks’ strength gains were almost all neural rather than structural.

Another study split adult males into two groups. One group did high-volume, lower-intensity full body lifting. The other did low-volume, higher-intensity full body lifting. After 8 weeks, both groups were bigger and stronger in the arms and legs, though the high-intensity group saw more significant growth.

Beginners may just need to get over the initial hump of training-induced muscle damage. One recent study put young men who hadn’t trained in the last six months on a ten-week, twice-a-week lower body lifting schedule, finding that muscle hypertrophy only occurred once muscle protein synthesis exceeded muscle damage. At week one, with muscle damage highest, hypertrophy was minimal. Week three saw less muscle damage and more hypertrophy. Week ten saw a huge drop in muscle damage and a huge spike in hypertrophy. As muscle damage dropped—a marker of adaptation to the training demands—hypertrophy spiked.

Your dominant limbs will probably gain strength faster than your non-dominant limbs, even if you train them equally. There shouldn’t be any difference in size gains, however.

All in all, hypertrophy doesn’t hit its stride until the 8-10 week mark.

As for endurance adaptations, it takes about eight weeks of exclusively low-level aerobic work to build a strong aerobic base. That forms the, well, base of the Primal Endurance program.

You can improve your VO2 max in two to four weeks using intense intervals, two weeks using 4-6 30-second all-out sprints 3x a week (or five weeks sprinting once a week), or continuous endurance training. Running half-mile intervals at full mile race pace is a good way to increase VO2 max fast, if you’re really into it.

Bone mineral density (BMD): Resistance training and high impact exercise maintain bone mineral density, but they can also increase it in elderly, middle-aged people, or anyone who needs it. In older adults, six months is enough to increase BMD, though most BMD studies last a year or two. In one study, overweight Latino kids needed 10 weeks of whole body vibration training for bone resorption to drop, a necessary precondition for increasing bone mineral density.

Whatever you do, don’t take these numbers as gospel.

People respond differently to training for a variety of reasons….

Genetics, for one, plays a role in how—and when—you respond to training.

Prior training status also changes things up. If you’re untrained, you’ll likely see faster results. A complete novice just getting into lifting weights can expect to add 5-10 pounds to the bar each workout for the first few weeks; that’s real strength. If you’re an experienced fitness buff, you’ll need more time. If you’re experienced but coming off a long layover, you’ll see a quick rebound—quicker in many cases than the untrained see.

Age is another factor to consider. The older you are, the longer it’ll take you to respond to training—in general.

Gender also modifies some of the time tables. A 12-week sprinting program helps both men and women lose body fat and improve VO2 max, but men lose fat more quickly, while women gain Vo2max more quickly.

Most importantly, consider that these studies report data only for subjects who follow the study protocol and do not drop out. The folks who don’t follow the program aren’t included in the results. So when I say 8 weeks is enough time to gain several pounds of lean mass, I’m talking about people who spend 8 weeks training three times a week, never skipping a workout and never training anything else.

That’s not you. You’re juggling work. You’re cooking dinner. You’re trying to squeeze in enough time to make it to the gym, or the CF class, or the track, or the trail. If you want to skip a workout, you can. There’s no research scientist compelling you to complete the program.

You’re also not doing just sprints or just weights or just endurance. You’re likely taking walks, lifting some heavy things, playing games, biking on the weekends, running a mile, doing a circuit. No one study can encompass the context of your life and the heterogeneity of your training.

A single workout can make you happier, sharper, and stronger. It can help you sleep, clear space in the muscles for glucose storage, and have a healthier response to food.

Then you do another one two days later, and those benefits only increase.

And another. With even more benefits.

My point? Don’t get hung up on the concrete benefits. They’re coming, and some of the best ones are already here. Let the training work. Just keep doing it.

Thanks for reading, everyone. As we approach the home stretch of the Challenge, I’d love to hear from you. What benefits have you noticed so far?

Take care, everybody.

Primal Kitchen Avocado Oil

TAGS:  Aging, body fat

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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25 thoughts on “How Long Does It Take for Fitness Benefits to Show?”

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  1. Totally agree that it’s not about the concrete benefits. Life is too complex for that. Moving my body just makes me feel better. Doing a mini workout on the bosu ball (25 pushups, 50 crunches, 100 squats) just makes me feel like I’m getting my day off to a good start. Long walks with my dog (that sometimes involve a little running) are a great break from sitting at my laptop. I get my best creative thoughts when I’m walking. Sometimes I use the time to listen to a podcast or call my mom, but many times I just let my mind wander while I enjoy the scenery. I feel more energetic and better able to focus when I come back inside. None of this can be measured, but it is all so worthwhile!

    1. That’s right. It’s the mental health benefits that I find the most immediate. Habitual exercise is also key. At some point you develop an internal voice that nags at you if you slack off on the habit. Exercise keeps you honest, and it keeps you focused. It relaxes and resets your mind. The physical benefits will come as they may.

      1. I often tell clients if they can choose between seeing me and going for a run, do the latter. I’m blessed with high reactivity to exercise. Almost immediately I feel relaxed and happy. Apparently not just endorphins, but also cannabinoids (see I have to thank Mark for opening my eyes to lifting. It’s something I did when younger, but have now had the opportunity to revisit at 50. It’s astonishing how good I feel during and after lifting. (Sleep better, too!)

  2. starting in your sixties—it doesn’t work very well after a lifetime of following the SAD diet and dealing with all the bone, joint, tendon and ligament problems —even when eating primal for a couple of years. things are reversing so that exercise is less of a problem but I can’t go full tilt yet! I keep hearing of vibration training helping with bone, tendon and ligament improvement (as well as cartiledge) —would this help an old timer to get up and running in a shorter period of time?

    1. Wondering that too, maybe I’ll stand on the washing machine next spin cycle and see if that is like one of those machines…

    2. Yeah – I started fitness at 49, and have been with free weights for less than a year, being 50 now. Yikes, the gains are slow going. But it’s the other things listed above that really help keep me focused.

      From what little I’ve read of vibration training, you have to resist against the vibration. So a washing machine may not quite cut it.

  3. I’ve been a constant gym goer for at least 9 years. Never more than now have I been focused on being healthy. I’ve been skinnier and more defined in the past (and let myself go), but I was unhealthy. Posts like this remind me that this is a life long race. The goal is to progress and get better every time I go to the gym.

    And that all of these strength and body changes start in the kitchen.


  4. I’ve really been enjoying lifting really heavy things (for me). I’ve been lifting heavy enough to fail after three or four reps, and feel great after doing it. Because of primal eating, my joints feel healthy enough to handle it, and I am seeing some real gains in strength. I haven’t lifted this heavy since college (15 years ago), and I’m 25 pounds lighter now than I was then.

  5. I am not a workoutaholic but I do enjoy an array of activities. Now, if there only was a mechanism that can signal bone regeneration as you said…. Perhaps it would have helped me avoid injury. I won’t bore you with the itsy bitsy but I really blew it this time, as I suffered stress fractures to my right ankle (a month ago and just confirmed via bone scan) while barefoot running and have to wear a high ankle boot for the next 6 weeks. Needless to say, I am climbing the walls right now. In general. the last two years were terrible for me injuries wise. And granted, I am nearing 60 but I feel and look (so I’m told) years younger the my peers and I simply don’t feel like slowing down. I also know that this type of injury is common even among elite athletes but it’s no consolation. I do wonder if it is a case of two much to soon consider I was out for 2 month due to hand surgery – there’s a point when the bone is at it’s weakest while regenerating and getting stronger, a question of form even though I am not heel striking and I’m soft landing, or some thing else altogether. The orthopedic surgeon who I consulted with, speculated that thyroid issues may effect bone integrity but it’s hard to get concrete answers. Feedback would be welcomed 😉

    1. Hey, TT, 63 y.o. guy here who always gets comments “you can’t be that old” yadda yadda but started having some injury issues about age 60. Do some research on UC-II. Secondarily, DONA Crystalline Glucosamine Sulfate. For your thyroid do some research on the synergy of Iodine, Ashwagandha, Korean ginseng and Guggul (there are products that contain the specific, researched amount). Hey, may have folks disagree with me here, but you might want to limit bare foot work to walking only. Try some swimming or bicycling for your HIIT or bite the bullet and use running shoes for your HIIT only. My two cents worth, all the best in your rehabbing! 🙂

      1. HealthyHombre, thank you for your thoughtful reply. I’ve heard of most but what is Secondarily? The problem is, most recommend consulting with a MD before using; Guggul in particular. But what do you do when the Dr’s don’t have a clue? I use Great lakes collagen daily, N-A-C and supplements that I know are beneficial (cod liver oil or Krill, MK-7, Magnesium, Zinc, B-50) and have eaten wholesome and fresh foods all my life but herbs are different altogether. And since I actually have Hashimoto, G6PD and excess Iron to top (I’m under the care of two experts) I must be cautious. Ashwagandha at least should be OK. Biking is awesome but that hand surgery I’ve mentioned, was the result of MTB accident back in 2014, that left me with limited wrist movement and no cartilage. So I can’t ride too far. Assuming you are using the above, is UC-II that much better then good old collagen (home made included)? The research on it is favorable. By the way, I’ve reached the same conclusion about running and will try to limit my barefoot activities to walking and short distance running; at least until I learn the cause of this injury…..except that I really hate wearing shoes now and as I’ve mentioned, I have hard time excepting getting “old”…My mom lived to 99 disease free and I think the key is, how we handle stress and make sure that our cortisol levels are under control.

    2. Wow your post could have been written by me, with different injuries (main one bad bad elbow)
      My extract:
      “I am nearing 65 but I feel and look (so I’m told) years younger the my peers and I simply don’t feel like slowing down.”
      What works for me you are already doing it: change of activities, like normal pullups give me pain, but with hands facing each other it is ok. Hand stand pushups against the wall ( a staple in the past) cannot do them: so be it, but I can hold the handstand for increasing lengths of time, you get the idea.
      My take: there are gazillion types of exercises, choose those that you can do and be happy 🙂

      1. Isn’t that something? I on the other hand, can still do pull ups but my ability to do chin ups is diminished since my injury and pushups are difficult as well. But yeah, there are plenty of other options and life goes on. Cheers 🙂

  6. Love this!! It’s so great to hear about all the other benefits of exercise that you can’t “see”. I think I’m going to hang this on my fridge for motivation 🙂

  7. I’ve been incorporating more squats and pushups into my day, but, for me, there’s some other issue rather than merely not seeing results. I wonder if you, or your readers, have any insight. Simply put, it just somehow feels embarrassing to exercise, even when it’s just me. Maybe it’s some other emotion rather than embarrassment, but I don”t have a name for it. I’m fine running 99% of all my transportation by bicycle. I love to walk. I go backpacking. I like to climb mountains. But when it comes to doing pushups or squats, or if I think about sprinting, some sort of shame takes over. Maybe part of me feels it’s narcissistic to do something only for the benefit of my body. Maybe it’s because my parents never exercised. Maybe it’s because I think of myself as a bookish rather than athletic person, (tied in with severe childhood asthma). I don’t know. It’s weird, but also hard to get around.

    1. Hi Paul, I can relate to your ambiguous feelings around publicly being seen doing certain movements. I hear you. It’s frustrating and debilitating, at least it was for me. I remember a time when I was in the 7th grade and wanted to lose weight. I’d gotten to an age where I was aware of the extra weight that had been put on over the years due to a very bad diet of junk food and inactivity. What I wanted to do to lose the weight was to run around my neighborhood (yea, primal, HIIT, or the internet just wasn’t around then ;)). I knew that if I did that I would feel good and it was at least a plan to target weight loss. However, that is what it remained. A plan. Even when my best friend told me she would get up early in the morning before school to run with me I was too embarrassed. My mind made up images of people whispering behind my back and gossiping about this goal of mine. Simply put, I cared too much about what others thought about me and I was too prideful to show and admit that I had areas where I needed improvement (later to be called perfectionism!). Because I never shared this with anyone at the time, no one ever told me a couple of things: A) people just aren’t paying attention, and if they are it’s for a hot minute before they get back to their own world to deal with, B) by not doing anything I was putting the perceived “others” ahead of myself (and that will certainly go no where) C) I needed to cultivate a bigger “WHY”; if I had a big enough vision there would be nothing standing in the way of getting what I wanted. This is just a whittled down version of my own experience and while what you’re trying to describe might not be quite the same I thought I’d share this with you in case it sheds some light for you 🙂 And of course, like Mark always says, it’s a life long journey!

      1. Thanks for the reply. I thought about it, after I posted the comment, and when I was young, my asthma was really bad, as in often trips to the emergency room and stays in oxygen tents, and once, when I was a teen, a stay in the ICU. Gym class was a nightmare. Whenever I began to move above a walk, I would have an asthma attack, so generally, I had a note that excused me from participating. Other times, I would walk desultorily back and forth on the basketball court or football field in whichever general direction the teams were moving. It’s too complicated for a comment, but I think I have a latent fear of exercise in terms of breathing, coupled with a lot of embarrassment. I’m also curious about self-perception. I come from a “large” family. At 200 pounds, (and 5’9″) I’m the rail thin one. I still remember being told I needed to gain weight when I was a boy because I was “nothing but skin and bones.” I can get my weight down to 165 with a little effort, which is closer to where it should be, but when I look in the mirror, I see someone who is “nothing but skin and bones.” None of the paleo books I have read seem to address fully these psychological issues that I’m sure we all face.

  8. I re-joined a gym after more than 10 yrs away from one. I was 49 yrs old & weighed 83 kg (183 lbs). Now nearly 2 yrs later I weigh 165 lbs and have added muscle, as well as being stronger. I go 3 or 4 times a week to lift weights. I also do boxing for fitness / HIIT with a trainer (who is 30 yrs younger than me!). I know that working out at a gym is not everyone’s cup of tea, but I’m glad that I do for the long-term benefits.

  9. Seven years in and Mark still astounds me at his ability to pull many facts and resources together to make a readable, succinct post!

    Yeah, I’m someone that needs pretty quick reinforcement of my work. These days, primary goal is weight loss (again.) Seeing those scale numbers drop let’s me be hungrier w/o heading for the fridge, and sends me back to the rec center for some bicycle sprints.

    Down six pounds in eleven days. Woo hoo…………… THAT’s motivation!

  10. I with I had read this before today AM, when I did my sprints:

    “If you were to hold a stethoscope up to your hamstrings immediately after a sprint session, you’d hear the *pop-pop-pop* of new mitochondria being spawned.”

    Next sprint day will bring the stethoscope

  11. Nice motivational article. Her’s an addition I grabbed off another page of MDA. Tendons are one of those things you won’t see improving but sure need improvement to keep you from falling apart. Yet because tendons receive less blood flow than muscle, and blood brings the nutrients and satellite cells used to repair and rebuild damaged tissue, they take a lot longer to respond to training than muscle. In one study, it took at least 2 months of training to induce structural changes in the Achilles’ tendon, including increases in collagen synthesis and collagen density. Other studies have found that it takes “weeks to months” of training to increase tendon stiffness. Meanwhile, we see structural changes to muscle tissue with just eight days of training.

  12. Good one Mark. 2 summers ago I thought I had a hernia and had to stop lifting weights for about a year. The ultrasound showed I tore my abdominal wall, and taking turns in my car required me to “hold my gut in”.

    You’d think after this long the abdominal wall would have healed, but I’m still liable to end up with sharp pains near the belly button if I lift too heavy.

    Yesterday I bought a mountain bike in an attempt to build my core strength back. I went on a brisk ride this morning. My legs feel engorged with blood. My arms do too. I’ve missed that feeling!

  13. Great text! Congratulations!
    I try to convince my students about the “hidden” benefits of exercise.
    Many still find that for exercise to be good it has to show immediate results.
    Inspired by that, I created an infographic and leave here the link, if anyone wants to know []

  14. quote from above: “As for endurance adaptations, it takes about eight weeks of exclusively low-level aerobic work to build a strong aerobic base. That forms the, well, base of the Primal Endurance program.” Does that mean that the lifting and sprinting should not be started until after 8 weeks of low-level aerobics? Thanks.