← What's That Rash?
What's That Rash?
Does magnesium work against muscle cramps?
00:19:52
Cramping muscles are common, whether they’re associated with exercise or not. Knowing what causes them can help people avoid them or treat them, but for many people it's not a simple story. Norman and Tegan talk through some of the theories behind this painful phenomenon, and why magnesium might not be the answer. References: Muscle cramps: A comparison of the two-leading hypothesis Influence of Hydration and Electrolyte Supplementation on Incidence and Time to Onset of Exercise-Associated Muscle Cramps Magnesium for skeletal muscle cramps - Cochrane Review A randomized, double-blind, placebo-controlled, multicenter study assessing the efficacy of magnesium oxide monohydrate in the treatment of nocturnal leg cramps Pickle Juice Intervention for Cirrhotic Cramps Reduction: The PICCLES Randomized Controlled Trial Australian Institute of Sport's sports supplement framework: pickle juice
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B
So, Tegan, you're always doing these exercises like climbing and you need to use your legs. And do your legs ever wake you up at night?
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A
Oh, like a muscle cramp? Yes, I've definitely had a really hectic calf cramp in the middle of the night one time it was actually while I was pregnant and I was like, if I can breathe through this pain, I'll be fine when I have a baby.
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B
And when the actual pain occurred, how did it compare?
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A
I honestly can't remember. But no, I got a cramp getting out of a swimming pool the other day and that was just embarrassing because I was just putting perched on the side of the pool.
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B
There's nothing else you can do, is there?
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A
Clutching onto my. You just gotta go upper thigh region. Exactly. So I'm very self interested in today's topic on what's that rash?
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B
Which is the show where we answer the health questions everybody's asking.
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A
When we say the health questions everyone's asking. This may actually be one of our most asked questions. David, Peter, Kevin, Alison and a second Kevin have all asked us why they get muscle cramps and how to stop them. So I suppose we should start with a bit of a definition of like, what is a cramp?
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B
Well, a cramp is a muscle spasm that comes on with its own mind. In a sense it can come on out of the blue. In my case, as I'm now just starting Pilates. Certain Pilates exercises like I've got to stop because I get a cramp. But it's a.
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A
You're a Pilates girly now, that's great.
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B
I am, I am. I'm having Pilates and can strongly recommend it.
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A
Are you like a reformer?
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B
Well, confession to make because I'm totally uncoordinated and if I went to a Pilates class, I'd get nothing out of it because I would be all over the shop. I'm actually having one on one at the moment at a huge expense just to learn how it's going. So really good instructor. And it's a mixture of reformer, bench mat, just anything to try and get me to understand water exercise.
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A
He's versatile. So you've been getting cramps because of Pilates?
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B
Well, I think that the movement brings it on. I've also been cycling a lot So I think that my muscles are probably a bit over exercised, which indeed is one of the causes of cramps is exercise. But really, coming back to your question, there are lots of causes of cramps, but the bottom line is it's intense pain in a muscle group, often the hamstrings, often the calf muscles, and very hard to control. And you start shouting out loud and you can't put your foot down because the contraction of the muscle affects how you move the. So it's hard to straighten out and so on.
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A
So I think we should clear some things up at the beginning because this is such a rich seam to mine. We'll focus on muscle cramps associated with exercise or the sorts of things you might get in the middle of the night. But we probably won't get to talk as much about menstrual cramps. Pregnancy cramps. Side stitches are also a sort of cramp. We might just save those up for a future WhatsApp rash.
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B
Yeah, and there are muscle cramps caused by disease states, cirrhosis, liver cirrhosis being one. Nobody fully understands why liver cirrhosis is associated with muscle cramps. I mean, liver cirrhosis is a serious disease. But when you look at quality of life with liver cirrhosis, with all sorts of other problems that it brings on, the muscle cramps are what people complain about most. So there are disease states which produce cramps as well. But let's focus, as you say, on exercise and what they call idiopathic muscle cramps, where they've really got no idea why they occur. And we're not talking about restless leg syndrome, which we have spoken about in the past on Watch that rash, and we'll have a link to that on our website.
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A
So I'm interested to know, Norman, when you say that you're getting cramps from your Pilates, are you getting it in the moment while you're performing the exercise or afterwards? Or are you getting it like in the middle of the night after you've had a big session?
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B
With Pilates, it's during the exercise. I suspect it's because I'm exercising those muscles with a lot of cycling I'm doing at the moment. So with Pilates, it's there, and then I go into a certain pose and I can't maintain it because my hamstrings go into a cramp. But it goes away pretty quickly. But I also get cramps during the night, which I associate with exercise and totally sympathize with people who get muscle cramps because very hard to deal with in the middle of the night and disturbs your sleep.
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A
So the reason I'm getting so anecdotal with this is because when we actually are looking at the evidence, which of course we will get into in just a moment, I'm always surprised at how little we know about the real nuts and bolts of what's happening inside a muscle when it's working. When we did our episode a few months ago now on electrical muscle stimulation and whether you can beef yourself up that way, we did another episode on Dom's delayed onset muscle soreness. And it's actually really frustrating how little we know about the sort of cause and effect of what's happening inside muscles.
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B
Yeah, we know quite a lot. We know about fast twitch and slow rich fibers. We know about the way electrolytes like sodium and potassium and magnesium work to get muscle contraction. But when it comes to something like cramps, nobody's really sure what's going on here. But apart from the fact that your muscles over contract and they don't relax.
- [05:30]
A
There are sort of two main theories around causes of cramps. Dehydration and loss of, I guess, essential salts and other minerals in your muscles. And the other one is just basically your muscles are all tired out.
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B
So the first study in this was back in 1908, which was actually a study of mine workers looking at a very high humid environment and found that there was an increased risk of muscle cramping. The thought was then that if you're sweating a lot, losing a lot of fluid, then you were being depleted of sodium, potassium, whatever, and that was inducing the muscles to contract and that perhaps dehydration was playing a role there as well.
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A
I mean, that's definitely what I feel like I've heard before. You know, you need to hydrate and maybe replenish certain electrolytes. Is this like the way you're saying that makes me think that maybe it's not as cut and dried as that?
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B
Well, it could be part of the process because, I mean, one of the drugs that can induce muscle cramps are diuretics. And diuretics cause you to lose fluid and electrolytes from your body. So that goes along with the idea that there's maybe something going on with your electrolytes. And when I say electrolytes again, I'm talking about sodium, potassium, chloride and so on. So there is some circumstantial evidence that electrolytes have something to do with this, but they bat and ball. This goes backwards and forwards. Muscle fatigue versus dehydration. And electrolytes and I mean, some poorly conducted studies, tiny, tiny studies suggesting that if you take a sports drink, in other words, electrolytes with carbohydrate before exercise, you reduce the incidence of muscle cramps. But you wouldn't go to town on that because it's such a tiny study. And you've got to be careful with overloading yourself before you go into a period of exercise. But one of the current popular theories is that there's a neurological imbalance in the spinal cord which sends the message to the muscles to contract. And that when there's that imbalance, for whatever reason, which could be dehydration, it could be genetic, it could be drug induced, it could be induced by dehydration. And what have you is that you get this imbalance and the balance switches from relaxation to contraction and it's hard to reverse that. What the evidence suggests is it's unusual for a muscle cramp where there's no disease associated with it, to last longer than about nine minutes, which is a.
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A
Long time, it's a lifetime if your muscle is cramping.
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B
But they do tend to go away by themselves.
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A
It's a really hard thing to study because inducing cramps is really hard, partly because we don't really know what causes them. It's hard to then stimulate them, I suppose is a better word. Some of the studies we looked at were sort of in a lab setting. But even for people who say that they cramp a lot, it's hard to get them to cramp in a lab. And then on the flip side, if people are out in a competition setting, it's really hard to control for the other variables. So it's actually quite a difficult thing to study.
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B
Yeah. And then what's your comparator finding people who are cramp free, the evidence suggests, when they've done surveys, is that most people will experience a cramp sometime in their life. It's not an unusual situation.
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A
The thing we actually have to talk about, if we're talking about cramps, is magnesium supplementation. Because that is the one thing that I feel like I've heard across the board for as long as I've sort of been in the health space. What evidence do we actually have that magnesium supplementation does anything?
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B
So I must confess that before.
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A
Oh, you take it, don't you?
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B
No, no. Well, no, no. Before Christmas, I was overseas and I had one night after the other of bad cramps. Goodness knows why. Could be dehydration from jet lag or what have you. And out of desperation, I looked up the evidence and I'll come back to the evidence in a minute. And notwithstanding that, I went into a chemist's shop in Salzburg and bought some magnesium and took it for a couple of nights. Sure enough, I didn't get any cramps. So was that the magnesium? Was it placebo?
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A
Was it the Salzburg effect?
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B
Maybe it pilsner was happening each night, who knows? The bottom line for magnesium is, I mean, some people swear by this, magnesium's not trouble free. People can get diarrhea on magnesium, so it's not a side effect. Free medication. And one of the most reliable sources of evidence is what we call the Cochrane Collaboration or the Cochrane Library, because we're often talking on what's that rash about studies that are too small, badly conducted. How would we know what the answer is? There've been quite a lot of studies done on magnesium, but not very high quality. But when you bring them all together and sort out the noise, you should be able to come to some kind of answer by aggregating the available studies. So the Cochrane Group, about five years ago did a review of magnesium for what they called skeletal muscle cramps and they could find no convincing evidence that it made a difference.
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A
Oh, that's disappointing and flies in the face of your enormous N1 trial that you did.
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B
That's right. But you know, as soon as I got on the plane home, I stopped taking it. But it's in the cupboard. Just in case.
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A
Just in case.
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B
And there have been some studies since which suggest that maybe it does have an effect. And you'll argue this toss backwards and forwards and you will find some studies with a small effect of magnesium. But when you sum it all up, probably not, but you're not doing yourself much harm if you decide to take it. But there is one caveat. What else is in the magnesium supplement that you're taking?
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A
Well, this has been in the news a lot recently because of people who have, I'm guessing this is where you're going, B6 toxicity. So vitamin B6, too much and it can cause really disabling nerve damage.
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B
Yeah, Peripheral neuropathy. And that's a very miserable condition.
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A
Yeah. And a really long recovery if it's reversible at all.
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B
So some preparations of magnesium are not pure magnesium. They have vitamin B6, it's not necessarily obvious. So you've got to look at the back of the packet, which I did in Austria, and they had pure magnesium, so I was okay there.
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A
So, yeah, buyer beware on that front. In terms of other Treatments, Norman, Because I feel like for a question that so many people have asked, we are not giving very satisfying answers so far. What other treatments are there around for muscle cramps and what do we know about how they work?
- [11:31]
B
Well, I'm sure every person who's written in to watch that rash about this has tried stretching and massaging. Because what do you do at 2 o' clock in the morning when you're screaming in pain and your partner wants to get back to sleep? Push my toes. Rub my calf for me, please, darling. Yes, yes. And then eventually it goes away. So like the magnesium, is it the stretching and massaging, is it the sharing of the agony with your partner in the middle of the night? I don't know. Heating pads, compression socks. Try that in a Brisbane summer.
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A
That would be for calf cramps.
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B
That would be for calf cramps. Bit hard for your hemisphere and there are vitamin deficiencies associated with it, particularly vitamin D. So a healthy, well rounded diet. It's not enough to recommend multivitamins, but a healthy rounded diet such as.
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A
I brought my bell with me this time.
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B
Well done. Might help. Whether or not Greek islanders get fewer muscle cramps than we do. I don't think that survey's been done.
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A
I think you and me might need to go on a research mission and find out.
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B
But here's the one that's on everybody's lips.
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A
Okay?
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B
Pickle juice.
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A
Yuck. I'd rather a cramp. Well, unless it's in a martini. No, that's olive juice. No, I don't want pickle juice at all, please. That's yucky.
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B
So the yuckiness might be. So they've done a very small trial and people remember I said at the beginning, have you got cirrhosis of the liver? Muscle cramps are a real problem. There's been a very small study, but in a reputable journal of pickle juice for cirrhosis of the liver and claimed to have got fewer attacks of muscle cramp as a result of the pickle juice. Very hard to do a placebo for pickle juice because you've got to get the same yuck factor. You kind of know whether you're on it or not. So really a dubious study. They are trying it on athletes for exercise induced cramps. There's not strong evidence. There's a little bit of evidence that it might work. And here's the theory for why it might work. And it's partly the yuck factor. What they think might happen is that the pickle juice hits the back of your throat and it affects the receptors, the nerve receptors at the back of your throat and actually shocks your nervous system, you know.
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A
Oh, that sort of astringent, that kind of puckering.
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B
Yeah. And therefore, in a sense, neurologically distracts your body from the muscle cramp.
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A
And that means if they had tried to do a placebo, it might not have worked because it might have induced the same response.
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B
Could be. And if it works, it's almost like counter irritation in a sense that your throat feels so crap that you suddenly the muscle doesn't matter anymore. And there are drugs, there are muscle relaxant drugs people use in medically induced cramps and so on, which does have some effect. People are talking about CBD oil for muscle cramps and spasms, but again, not proven. Yet. Another one is quinine, which did actually have Therapeutic Goods Administration approval, but it was withdrawn about 20 years ago.
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A
That's the anti malarial.
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B
Yeah. But also has effect on the nervous system, but it's a very toxic drug. It can reduce the number of platelets in your blood, causing you to bleed and has been associated with fatality. So it's no longer approved for that use.
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A
Okay, so we didn't read out everyone's individual questions because it would have taken forever. But David does make a point that I want to highlight. David says various friends have given me various advice, all ignored about what has worked for them, but I would like something a little more authoritative. Norman, can we give David anything authoritative to deal with his leg cramps?
- [15:05]
B
Well, if you feel like trying magnesium, a little bit of evidence maybe that it works. But, you know, just be careful of upset tummy and so on, and just be critical of it. It's hard when it's once in a blue moon that you get muscle cramps. Would you take it every night just because once a week you get muscle cramps? Probably not. But if you've got a run of them, it's also worth. If you're getting muscle cramps out of the blue, you're not over exercising and there's no obvious reason for it. I think you should check in with your GP just to make sure there's nothing else going on. But most people are pretty fit and healthy.
- [15:38]
A
Just like with anything, if your body's doing something dramatically different to what it used to be doing, check in with your gp.
- [15:44]
B
That's right, because there are rare causes of muscle cramps, which they are rare, but if it's coming in out of the blue and it's continuous, then you really gotta get it checked out.
- [15:53]
A
So I mean, if David's friends are telling him what worked for them, I mean, maybe just do what they say.
- [15:58]
B
Well, that's right. We are talking about anecdote here. As long as they're not suggesting taking something like mercury or something terribly poisonous, go for it.
- [16:08]
A
Well, David, Peter, Kev, Allison and Kevin, thank you so much for sending in your questions. If you have a question you would like us to have a go at finding some strong evidence for, email us. We are that rashbc.net au and we're.
- [16:21]
B
Still open to N of 1 trials. Just let us know what happened.
- [16:24]
A
And that email address is also where you can send your feedback to us. Jan has emailed us Norman saying lately, I heard from Dr. Google that I can boost my vitamin D levels without supplements by being outdoors and getting more sunshine, which would be cheap and easy, which to me on face value sounds okay. But the information Jan received also suggested that sunscreen was a bit of a beat up. And Jan has just listened to the excellent podcast Lab Notes, which is produced by our colleague Belinda Smith about why the Australian sun has more sting to it. You should definitely go and listen to Lab Notes if you haven't already. It's a really good explainer. But Jan is asking, how do I elevate my vitamin D levels without supplements or frying my face off?
- [17:07]
B
Well, you do go out in the sun and you get the recommended levels of sun according to the time of year. And I think most cancer councils have that advice. Sunscreen is not a beat up. You do need sunscreen in Australia. We have very vicious sun. Just remember Hobart is at the same equivalent latitude as Rome, so that's how much UV we get in Australia here. So it's very strong. And sunscreen does work, but sunscreen, none of us put on sunscreen perfectly. So when you're out in the sun with sunscreen on, you're still getting your vitamin D levels boosted in reality because we're not slapping it on to the extent that is really going to block it out.
- [17:45]
A
And we actually did talk about this in a bit more depth in a previous WhatsApp rash. We'll put the link to that episode in our show Notes, but it's called is there such a thing as too much sun protection? So have a listen to that one as well, Jan, if that's useful.
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B
And another reminder for you, if you've got Nothing on on March 30th or.
- [18:02]
A
If you do have something on, cancel it because we've got a live show.
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B
For you at the World Science Festival in Brisbane in the Queensland Museum Theatre.
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A
It's March 30th at 10am yes, you do need to buy a ticket for this event, but please do. We would love to see you there. We will be answering your questions live. And if you bring along your own Mediterranean diet, bell, I will. Last year I told someone that I'd give them a kiss on the lips and my husband listened and he didn't like them very much. So maybe I'll just give you like a lettuce leaf or something.
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B
A fig leaf. I think what you should give them is a fig leaf. Fig leaf. And I won't be kissing anybody, but I will enjoy your company there and, you know, catch a plane to Brisbane. It's going to be worth it.
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A
It'll be worth it. That's World Science Festival Brisbane. Search whatsaturash on their website. Book your tickets and we'll see you on March 30th at 10am but meantime.
- [18:52]
B
We'Ll see you next week.
- [18:53]
A
See you then.