Why are my muscles sore after exercise? Hint: it’s nothing to do with lactic acid

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As many of us hit the gym or go for a run to recover from the silly season, you might notice a bit of extra muscle soreness.

This is especially true if it has been a while between workouts.

A common misunderstanding is that such soreness is due to lactic acid build-up in the muscles.

Research, however, shows lactic acid has nothing to do with it. The truth is far more interesting, but also a bit more complex.

It’s not lactic acid

We’ve known for decades that lactic acid has nothing to do with muscle soreness after exercise.

In fact, as one of us (Robert Andrew Robergs) has long argued, cells produce lactate, not lactic acid. This process actually opposes not causes the build-up of acid in the muscles and bloodstream.

Unfortunately, historical inertia means people still use the term “lactic acid” in relation to exercise.

Lactate doesn’t cause major problems for the muscles you use when you exercise. You’d probably be worse off without it due to other benefits to your working muscles.

Lactate isn’t the reason you’re sore a few days after upping your weights or exercising after a long break.

So, if it’s not lactic acid and it’s not lactate, what is causing all that muscle soreness?

Muscle pain during and after exercise

When you exercise, a lot of chemical reactions occur in your muscle cells. All these chemical reactions accumulate products and by-products which cause water to enter into the cells.

That causes the pressure inside and between muscle cells to increase.

This pressure, combined with the movement of molecules from the muscle cells can stimulate nerve endings and cause discomfort during exercise.

The pain and discomfort you sometimes feel hours to days after an unfamiliar type or amount of exercise has a different list of causes.

If you exercise beyond your usual level or routine, you can cause microscopic damage to your muscles and their connections to tendons.

Such damage causes the release of ions and other molecules from the muscles, causing localised swelling and stimulation of nerve endings.

This is sometimes known as “delayed onset muscle soreness” or DOMS.

While the damage occurs during the exercise, the resulting response to the injury builds over the next one to two days (longer if the damage is severe). This can sometimes cause pain and difficulty with normal movement.

The upshot

Research is clear; the discomfort from delayed onset muscle soreness has nothing to do with lactate or lactic acid.

The good news, though, is that your muscles adapt rapidly to the activity that would initially cause delayed onset muscle soreness.

So, assuming you don’t wait too long (more than roughly two weeks) before being active again, the next time you do the same activity there will be much less damage and discomfort.

If you have an exercise goal (such as doing a particular hike or completing a half-marathon), ensure it is realistic and that you can work up to it by training over several months.

Such training will gradually build the muscle adaptations necessary to prevent delayed onset muscle soreness. And being less wrecked by exercise makes it more enjoyable and more easy to stick to a routine or habit.

Finally, remove “lactic acid” from your exercise vocabulary. Its supposed role in muscle soreness is a myth that’s hung around far too long already.The Conversation

Robert Andrew Robergs, Associate Professor – Exercise Physiology, Queensland University of Technology and Samuel L. Torrens, PhD Candidate, Queensland University of Technology

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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  • Carbonated Water: For Weight Loss, Satiety, Or Just Gas?

    10almonds is reader-supported. We may, at no cost to you, receive a portion of sales if you purchase a product through a link in this article.

    There are two main mechanisms of action by which sparkling water is considered to help satiety and/or weight loss; they are:

    1. It “fills us up” such that we feel fuller sooner, and thus eat less, and thus (all other things being equal) perhaps lose weight
    2. The carbon dioxide is absorbed into the bloodstream, where (as a matter of chemistry) it improves glucose metabolism, thus lowering blood sugars and indirectly leading (potentially) to weight loss, but even if not, lowered blood sugars are good for most people most of the time, right?

    However, there are just a few problems:

    Full of gas?

    Many people self-report enjoying sparkling water as a way to feel fuller while fasting (or even while eating). However, the plural of “anecdote” is not “data”, so, here be data… Ish:

    ❝In order to determine whether such satiating effects occur through oral carbonic stimulation alone, we conducted modified sham-feeding (SF) tests (carbonated water ingestion (CW), water ingestion (W), carbonated water sham-feeding (CW-SF), and water sham-feeding (W-SF)), employing an equivalent volume and standardized temperature of carbonated and plain water, in a randomized crossover design.

    Thirteen young women began fasting at 10 p.m. on the previous night and were loaded with each sample (15ºC, 250 mL) at 9 a.m. on separate days. Electrogastrography (EGG) recordings were obtained from 20 min before to 45 min after the loading to determine the power and frequency of the gastric myoelectrical activity. Appetite was assessed using visual analog scales. After ingestion, significantly increased fullness and decreased hunger ratings were observed in the CW group. After the load, transiently but significantly increased fullness as well as decreased hunger ratings were observed in the CW-SF group. The powers of normogastria (2-4 cpm) and tachygastria (4-9 cpm) showed significant increases in the CW and W groups, but not in the CW-SF and W-SF groups. The peak frequency of normogastria tended to shift toward a higher band in the CW group, whereas it shifted toward a lower band in the CW-SF group, indicating a different EGG rhythm.

    Our results suggest that CO2-induced oral stimulation is solely responsible for the feeling of satiety.❞

    ~ Dr. Maki Suzuki et al.

    Now, that’s self-reported, and a sample size of 13, so it’s not the most airtight science ever, but it is at least science. Here’s the paper, by the way:

    Oral Carbonation Attenuates Feeling of Hunger and Gastric Myoelectrical Activity in Young Women

    Here’s another small study with 8 people, which found that still and sparkling water had the exact same effect:

    Effect of carbonated water on gastric emptying and intragastric meal distribution

    However, drinking water (still or sparkling) with a meal will not have anywhere near the same effect for satiety as consuming food that has a high water-content.

    See also: Some Surprising Truths About Hunger And Satiety ← our main feature in which we examine the science of volumetrics, including a study that shows how water incorporated into a food (but not served with a food) decreases caloric intake.

    As an aside, one difference that carbonation can make is to increase ghrelin levels—that’s the hunger hormone (the satiety hormone is leptin, by the way). This one’s a rat study, but it seems reasonable that the same will be true of humans:

    Carbon dioxide in carbonated beverages induces ghrelin release and increased food consumption in male rats: implications on the onset of obesity

    …which is worth bearing in mind even if you yourself are not, in fact, a male rat.

    The glucose guzzler?

    This one has simply been the case of a study being misrepresented, for example here:

    Fizzy water might aid weight loss by providing a small boost to glucose uptake and metabolism

    The idea is that higher levels of carbon dioxide in the blood mean faster glucose metabolism, which is technically true. Now, often “technically true” is the best kind of true, but not here, because it’s simply not useful.

    In short, we produce so much carbon dioxide as part of our normal respiratory processes, that any carbon dioxide we might consume in a carbonated water is barely a blip in the graph.

    Oh, and that article we just linked? Even within the article, despite running with that headline, the actual scientists quoted are saying such things as:

    ❝While there is a hypothetical link between carbonated water and glucose metabolism, this has yet to be tested in well-designed human intervention studies❞

    ~ Professor Sumantra Ray

    Note: the word “hypothetical” means “one level lower than theoretical”. This is very far from being a conclusion.

    And the study itself? Wasn’t even about carbonated water, it was about kidney dialysis and how the carbon dioxide content can result in hypoglycemia:

    The mechanism of hypoglycemia caused by hemodialysis

    …which got referenced in this paper (not a study):

    Can carbonated water support weight loss?

    …and even that concluded:

    ❝CO2 in carbonated water may promote weight loss by enhancing glucose uptake and metabolism in red blood cells.

    However, the amount is so small that it is difficult to expect weight loss effects solely from the CO2 in carbonated water.

    Drinking carbonated water may also affect blood glucose measurements.❞

    Note: the word “may”, when used by a scientist and in the absence of any stronger claims, means “we haven’t ruled out the possibility”.

    What breaking news that is.

    Stop the press! No, really, stop it!

    So… What does work?

    There are various ways of going about actually hacking hunger (and they stack; i.e. you can use multiple methods and get cumulative results), and we wrote about them here:

    Hack Your Hunger

    Enjoy!

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  • Low-Dose Aspirin & Anemia

    10almonds is reader-supported. We may, at no cost to you, receive a portion of sales if you purchase a product through a link in this article.

    We recently wrote about…

    How To Survive A Heart Attack When You’re Alone

    …and one of the items was “if you have aspirin readily available, then after calling an ambulance is the time to take it—but don’t exert yourself trying to find some”.

    But what of aspirin as a preventative?

    Many people take low-dose aspirin daily as a way to reduce the risk of atherothrombosis specifically (and thus, indirectly, they hope to reduce the risk of heart attacks).

    The science of how helpful this is both clear and complicated—that is to say, the stats are not ambiguous*, but there are complicating factors of which many people are unaware.

    *it will reduce the overall risk of cardiovascular events, but will not affect CVD mortality; in other words, it may improve your recovery from minor cardiac events, but is not likely to save you from major ones.

    And also, it has unwanted side effects that can constitute a more relevant threat for many people. We’ll share more on that at the end of today’s article, but first…

    A newly identified threat from daily aspirin use

    A large (n=313,508) study of older adults (median age 73) were sorted into those who used low-dose aspirin as a preventative, and those who did not.

    The primary outcome was incidence of anemia sufficient to require treatment, and the secondary outcome was major bleeding. And, at least 1 in 5 of those who experienced anemia also experienced bleeding.

    The bleeding issue was not “newly identified” and will not surprise many people; after all, the very reason that aspirin is taken as a CVD preventative is for its anti-clotting property of allowing blood to flow more freely.

    The anemia, however, has been getting increasing scientific scrutiny lately, after long going unnoticed in the wild. Given that anemia also gives the symptom “dizziness”, this is also a significant threat for increasing the incidence of falls in the older population, too, which can of course lead to serious complications and ultimately death.

    Here’s the paper itself:

    Low-Dose Aspirin and Risk of Anaemia in Older Adults: Insights from a Danish Register-based Cohort Study

    Want to know more?

    As promised, here’s what we wrote previously about some of aspirin’s other risks:

    Aspirin, CVD Risk, & Potential Counter-Risks

    Take care!

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  • Flax Seeds vs Pumpkin Seeds – Which is Healthier?

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    Our Verdict

    When comparing flax seeds to pumpkin seeds, we picked the flax.

    Why?

    Looking at the macros first, they are equal on protein, and flax seeds have a lot more fiber while pumpkin seeds have a lot more carbs. We’re going to prioritise fiber over carbs and call this a win for flax.

    In terms of vitamins, flax seeds have a lot more of vitamins B1, B2, B3, B5, B6, B7, B9, C, E, K, and choline, while pumpkin seeds have a tiny bit more vitamin A. An easy win for flax here.

    When it comes to minerals, flax has multiples more calcium, copper, iron, magnesium, manganese, phosphorus, and selenium, while pumpkin seeds have more zinc. Another win for flax.

    Adding up the sections makes for a clear overall win for flax, but by all means enjoy either or both; diversity is good!

    Want to learn more?

    You might like to read:

    What’s Your Plant Diversity Score? ← seeds count as plants!

    Enjoy!

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  • The Unchaste Berry

    10almonds is reader-supported. We may, at no cost to you, receive a portion of sales if you purchase a product through a link in this article.

    A Chasteberry, By Any Other Name…

    Vitex agnus castus, literally “chaste lamb vine”, hence its modern common English name “chasteberry”, gets its name from its traditional use as an anaphrodisiac for monks (indeed, it’s also called “monk’s pepper”), which traditional use is not in the slightest backed up by modern science.

    Nor is its second most popular traditional use (the increase in production of milk) well-supported by science either:

    ❝Its traditional use as a galactagogue (i.e., a substance that enhances breast milk production) is not well supported in the literature and should be discouraged. There are no clinical data to support the use of chasteberry for reducing sexual desire, which has been a traditional application❞

    ~ Dr. Beatrix Roemheld-Hamm

    Source: American Family Physician | Chasteberry

    Both of those supposed effects of the chasteberry go against the fact that it has a prolactin-lowering effect:

    ❝It appears that [chasteberry] may represent a potentially useful and safe phytotherapic option for the management of selected patients with mild hyperprolactinaemia who wish to be treated with phytotherapy.❞

    ~ Dr. Lídice Puglia et al.

    Source: Vitex agnus castus effects on hyperprolactinaemia

    Prolactin, by the way, is the hormone that (as the name suggests) stimulates milk production, and also reduces sexual desire (and motivation in general)

    • In most women, it spikes during breastfeeding
    • In most men, it spikes after orgasm
    • In both, it can promote anhedonic depression, as it antagonizes dopamine

    In other words, the actual pharmacological effect of chasteberry, when it comes to prolactin, is the opposite of what we would expect from its traditional use.

    Ok, so it’s an unchaste berry after all…. Does it have any other claims to examine?

    Yes! It genuinely does help relieve PMS, for those who have it, and reduce menopause symptoms, for those who have those, for example:

    ❝Dry extract of agnus castus fruit is an effective and well tolerated treatment for the relief of symptoms of the premenstrual syndrome.❞

    ~ Dr. Robert Schellenberg

    Source: Treatment for the premenstrual syndrome with agnus castus fruit extract: prospective, randomised, placebo controlled study

    ❝That [Vitex agnus castus] trial indicated strong symptomatic relief of common menopausal symptoms❞

    ~ Dr. Barbara Lucks

    Source: Vitex agnus castus essential oil and menopausal balance: a research update

    Is it safe?

    Generally speaking, yes. It has been described as “well-tolerated” in the studies we mentioned above, which means it has a good safety profile.

    However, it may interfere with some antipsychotic medications, certain kinds of hormone replacement therapy, or hormonal birth control.

    As ever, speak with your doctor/pharmacist if unsure!

    Where can I get some?

    We don’t sell it, but here for your convenience is an example product on Amazon

    Enjoy!

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  • Insomnia? High blood pressure? Try these!

    10almonds is reader-supported. We may, at no cost to you, receive a portion of sales if you purchase a product through a link in this article.

    Your Questions, Our Answers!

    Q: Recipes for insomnia and high blood pressure and good foods to eat for these conditions?

    A: Insomnia can be caused by many things, and consequently can often require a very multi-vector approach to fixing it. But, we’ll start by answering the question you asked (and probably address the rest of dealing with insomnia in another day’s edition!):

    • First, you want food that’s easy to digest. Broadly speaking, this means plant-based. If not plant-based, fish (unless you have an allergy, obviously) is generally good and certainly better than white meat, which is better than red meat. In the category of dairy, it depends so much on what it is, that we’re not going to try to break it down here. If in doubt, skip it.
    • You also don’t want blood sugar spikes, so it’s good to lay off the added sugar and white flour (or white flour derivatives, like white pasta), especially in your last meal of the day.
    • Magnesium supports healthy sleep. A fine option would be our shchi recipe, but using collard greens rather than cabbage. Cabbage is a wonderful food, but collard greens are much higher in magnesium. Remember to add plenty of mushrooms (unless you don’t like them), as they’re typically high in magnesium too.

    As for blood pressure, last month we gave tips (and a book recommendation) for heart health. The book, Dr. Monique Tello’s “Healthy Habits for Your Heart: 100 Simple, Effective Ways to Lower Your Blood Pressure and Maintain Your Heart’s Health”, also has recipes!

    Here’s one from the “mains” section:

    Secret Ingredient Baltimore-Style Salmon Patties with Not-Oily Aioli

    ❝This is a family favorite, and no one knows that it features puréed pumpkin! Most salmon cake recipes all for eggs and bread crumbs as binders, but puréed pumpkin and grated carrot work just as well, lend a beautiful color, and add plenty of fiber and plant nutrients. Canned salmon is way cheaper than fresh and has just as much omega-3 PUFAs and calcium. Serve this alongside a salad (the Summer Corn, Tomato, Spinach, and Basil Salad would go perfectly) for a well-rounded meal.❞

    Serves 4 (1 large patty each)

    Secret Ingredient Baltimore-Style Salmon Patties:

    • 1 (15-oz) can pink salmon, no salt added
    • ½ cup puréed pumpkin
    • ½ cup grated carrot (I use a handheld box grater)
    • 2 tablespoons minced chives (Don’t have chives? Minced green onions or any onions will do)
    • 2 teaspoons Old Bay Seasoning
    • 1 tablespoon olive oil
    • ½ large lemon, sliced, for serving

    Not-Oily Aioli:

    • ½ cup plain low-fat Greek yogurt
    • Juice and zest from ½ large lemon
    • 1 clove garlic, crushed and minced fine
    • 2 tablespoons chopped fresh dill
    1. For the patties: mix all the ingredients for the salmon patties together in a medium bowl
    2. Form patties with your hands and set on a plate or tray (you should have 4 burger-sized patties)
    3. Heat oil in a large skillet over medium heat.
    4. Set patties in a skillet and brown for 4 minutes, then carefully flip.
    5. Brown the other side, then serve hot.
    6. For the Aioli: mix all the ingredients for the aioli together in a small bowl.
    7. Plop a dollop alongside or on top of each salmon patty and serve with a spice of lemon.

    Per serving: Calories: 367 | Fat: 13.6g | Saturated Fat: 4.4g | Protein: 46g | Sodium: 519mg | Carbohydrates: 13.2g | Fiber: 1.3g | Sugars: 9g | Calcium: 505mg | Iron: 1mg | Potassium 696mg

    Notes from the 10almond team:

    • If you want to make it plant-based, substitute cooked red lentils (no salt added) for the tinned salmon, and plant-based yogurt for the Greek yogurt
    • We recommend adding more garlic. Seriously, who uses 1 clove of garlic for anything, let alone divided between four portions?
    • The salads mentioned are given as recipes elsewhere in the same book. We strongly recommend getting her book, if you’re interested in heart health!

    Do you have a question you’d like to see answered here? Hit reply or use the feedback widget at the bottom; we’d love to hear from you!

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  • Dioscorea Villosa: Hormones, Arthritis, & Skin

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    On A Wild Yam Chase?

    We recently came across a supplement blend that had wild yam extract as a minor ingredient. Our plucky (and usually very knowledgable) researcher had never heard of its use before, so she set about doing her thing. This is what she found…

    What health claims are made?

    Wild yam extract (Dioscorea villosa) is traditionally sold and used for:

    • Balancing hormones
    • Combating arthritis
    • Anti-aging effects for the skin

    Does it balance hormones?

    First, as a quick catch-up, we’ll drop a previous article of ours for your convenience:

    What Does “Balance Your Hormones” Even Mean?

    We couldn’t find almost any studies into wild yam extract’s hormone-balancing effects, but we did find one study, and:

    ❝Symptom scores showed a minor effect of both placebo and active treatment on diurnal flushing number and severity and total non-flushing symptom scores, and on nocturnal sweating after placebo, but no statistical difference between placebo and active creams.

    This study suggests that short-term treatment with topical wild yam extract in women suffering from menopausal symptoms is free of side-effects, but appears to have little effect on menopausal symptoms❞

    …which is a very thorough, polite, sciencey way of saying “wow, this does so many different kinds of nothing”

    Source: Effects of wild yam extract on menopausal symptoms, lipids and sex hormones in healthy menopausal women

    On the one hand, this was a small study (n=23). On the other hand, it was also literally the only study we could find.

    Does it combat arthritis?

    Maybe! We again didn’t find much research into this but we did find two in vitro studies that suggests that diosgenin (which can be derived from wild yam extract) helps:

    And we also found a rodent study that found that wild yam extract specifically helped against “acetic acid-induced writhing and formalin-induced pain“, and put that down to anti-inflammatory properties:

    Read: Bioassay-guided evaluation of Dioscorea villosa – an acute and subchronic toxicity, antinociceptive and anti-inflammatory approach

    So, none of these studies tell us much about whether it would be helpful for humans—with or without arthritis, and hopefully without “acetic acid-induced writhing and formalin-induced pain”.

    However, they do suggest that it would be reasonable to test in humans next.

    You might prefer:

    Does it keep skin young?

    Again, research is thin on the ground, but we did find some! A study with wild-yam-derived diosgenin found that it didn’t make anything worse, and otherwise performed a similar role to vitamin A:

    Read: Novel effects of diosgenin on skin aging

    That was on rats with breast cancer though, so its applicability to healthy humans may be tenuous (while in contrast, simply getting vitamin A instead is a known deal).

    Summary

    • Does it balance hormones? It probably does little to nothing in this regard
    • Does it combat arthritis? It probably has anti-inflammatory effects, but we know of no studies in humans. There are much more well-established anti-inflammatories out there.
    • Does it keep the skin young? We know that it performs a role similar to vitamin A for rats with breast cancer, and didn’t make anything worse for them. That’s the extent of what we know.

    Where can I get some?

    In the unlikely event that the above research review has inspired you with an urge to buy wild yam extract, here is an example product for your convenience.

    Some final words…

    If you are surprised that we’re really not making any effort to persuade you of its merits, please know that (outside of the clearly-marked sponsor section, which helps us keep the lights on, so please do visit those) we have no interest in selling you anything. We’re genuinely just here to inform 🙂

    If you are wondering why we ran this article at all if the supplement has negligible merits, it’s because science is science, knowledge is knowledge, and knowing that something has negligible merit can be good knowledge to have!

    Also, running articles like this from time to time helps you to know that when we do sing the praises of something, it’s with good reason

    Take care!

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