A (2:04)

Anyway, we're sort of talking kind of along these lines today here on what's that rash we're talking about? I guess health myths. One health myth in particular.

B (2:14)

Watch that rash, which is the podcast where we answer the health questions that everyone's asking.

A (2:22)

Today's question comes from Sarah, who is asking about waiting an hour after eating before swimming. Sarah actually wanted to talk about waiting. All sorts of things that are no longer necessary that were health advice. But I think this one is put.

B (2:35)

Your nail cuttings wherever you like, Sarah. You're free to go whether you're Jewish or not. You know, go for it.

A (2:40)

But yes, specifically waiting an hour after eating before swimming. Is this something that you were told when you were a wee boy?

B (2:47)

100%, yeah.

A (2:48)

An hour. Was that the length of time that you were advised?

B (2:50)

Yeah, it was at least an hour. Yeah.

A (2:52)

I thought it was 20 minutes in my house. Probably slightly more relevant for me as a kid growing up in Queensland than as a boy Grove in Glasgow.

B (3:00)

You're probably keen on going in the water. Cause it was warmer. That's right.

A (3:03)

We were desperate to get in the pool. So, yeah, let's talk about what the claim is and then we can debunk it. Like, spoiler alert. This is a debunking episode. I've heard 20 minutes, I've heard an hour, I've even heard two hours. Would you like to know where it first appeared in writing?

B (3:19)

Yes, I would.

A (3:21)

Boy scout's handbook from 1908.

B (3:24)

Oh, really? What did it say?

A (3:25)

It said it's actually really cute. Like it's a little. I can see the page, page from the Boy Scouts handbook. It's got a young man standing in front of the tent that's pitched and talking about the fact that no scout can consider himself a full blown scout until he is able to swim and to save a life in the water. But there are dangers about bathing for which every sensible scout will be prepared. And then it talks at length about the danger of cramp. And if you start swimming before your food is digested, you're going to get cramp. It doubles you up in extreme pain so that you cannot move your arms or legs and down you go. It says you may drown and it will be your own fault. And then it says many lives are lost every summer through foolishness on the part of boys bathing, because they don't think of these things. Bathing must only be permitted in safe places and under strict supervision.

B (4:16)

And the interesting thing about that is that in terms of what your parents used to tell you, they used to say cramp, you know, and just reading that about cramp, there's two aspects to what they thought happened. One was muscle cramps. But most of the time the cramps they were talking about were actually stomach cramps, which also could be called a stitch.

A (4:38)

Yes.

B (4:38)

Where you feel this acute sort of Muscular pain in your abdomen.

A (4:42)

I'm curious about this line. Many lives are lost every summer. That the idea that it's like this epidemic of people drowning because they got in water before straight after eating food. I guess in 1908 you could kind of write whatever you wanted in a handbook and it was much harder for people to fact check you.

B (5:00)

Yeah, long term epidemic epidemiological research was just not a strong point. But when it has been done and they've looked in the data on drownings, this doesn't feature.

A (5:09)

So there have been quite a few studies on this, one of which was conducted in the 1960s where they got people to eat a meal and then go for a swim and see how they went. Would you like to know what the meal consisted of?

B (5:22)

Go on.

A (5:23)

Roast beef, gravy, mashed potatoes, peas, salad with French dressing, a roll with butter, a glass of milk and a glass of water. I'm having stomach cramps just looking at that list and I'm nowhere near a pool right now.

B (5:36)

Well, if you're going to test the theory, you've got to test it full on. It can't just be, you know, a peanut butter sandwich or a Vegemite sandwich.

A (5:43)

No, exactly. Would you like to know what the, what the findings were though?

B (5:47)

Yeah. What were the findings?

A (5:48)

No effect on swimming performance, Minimal side effects at different time intervals after that meal. So even with the roast beef, gravy, bread roll, a glass of milk, that's the part that really does me about that meal. But yeah, no effect on semicirculation.

B (6:04)

If your lactose intolerance, you would have got some reflux as you were going. But you know, put it outside.

A (6:10)

That's true. So I guess to quite quickly sort of debunk this, this is where it's come from. One thing I should say in terms of that time period and people having troubles in the water, there was a report in the New York Times about people drowning after getting a cramp. There's a particular story that came out in 1908, so the same year as the Boy Scout manual was published. So maybe this kind of fed into it a little bit about seven different people getting into trouble swimming in the east river in New York City. This is in the New York Times. One of the things that's very enjoyable about reading this story is that every single man is introduced with their full name and their street address. John Milton of 500 670th street died. Unfortunately, there was a James Alpha who lives at 1513 Avenue A who sprang to his aid. George Rubin of 436 East 75th street also helped from a rowboat that they were in. I can't imagine. I cannot imagine a single news story these days where every single person in it is introduced with their home address.

B (7:15)

No, you just go onto Instagram to find out where they live.

A (7:17)

That's true, but I'm making a bit light of it. This was people or someone died, others exhausted in trying to save them. It obviously was a source of anxiety that people could get into trouble swimming and drown. What about this idea of cramps versus stitches, though?

B (7:35)

If you get a stitch, for some reason, it's more common on the right side of your abdomen than on the left. No idea why.

A (7:42)

I remember hearing as a kid this is okay. More things that we heard as kids that I've never examined as an adult.

B (7:46)

Were you walking in your bare feet?

A (7:49)

I lived in Queensland, of course I was. No, it was about. Oh, I went to a school where for some horrible, torturous reason and they would make us run like a lap around the whole school every morning in winter. And I think it was like cross country training and it was my most dreaded time of day. But you would often get a stitch? Well, I would because I wasn't used to running and I. Someone told me it was like your liver jiggling around. Is that a thing?

B (8:15)

Well, some people say that there is a relationship with eating and a stitch and that you're peritoneum, the membrane that's surrounding your gut, can get irritated if your stomach is bloated and there's too much pressure on the peritoneum and maybe some of the metabolites from your food go across into your peritoneum that gets irritated and that irritates the muscle. I mean, that's the theory which nobody really knows the answer to it. There's also the idea that if you exercise and you are a bit dehydrated or you've got an electrolyte imbalance, that your muscles can be going to cramp more easily in that situation. But that's muscle cramps in general rather than stitches. In terms of more you're talking about running, you know, going for a run and extreme exercise outside the water. They do say that you should generally not have a large meal immediately before you do excessive exercise. You should be drinking, you should make sure you're hydrated, but not over hydrated. And you just don't want your stomach to be bloated before you do extreme physical exercise or, you know, vigorous exercise. Some people say you should avoid sugary drinks as well. But that's probably, you know, the whole thing about carbohydrates and exercise is the story for another. What's that rash?

A (9:32)

I mean, I should say, just to bring the evidence to a bit of a tidy bow, the International Life Saving Federation actually put out a medical position statement this in 2014, whether there was any evidence that we should wait after eating before swimming. Basically, the statement that they came to was, no, there's no evidence that eating before swimming increases the risk of drowning. So apart from one Boy scout manual from 1908, where else could this idea have come from?

B (10:01)

Well, I think that the much more pertinent point is parents having a rest and not having to supervise kids at the beach. You know, so after dinner, when they're feeling. After lunch, when they're feeling woozy and wanting a little nap. They can't have a nap when the kids are in the pool.

A (10:17)

Oh, actually, yes, speaking of wanting to have a nap after eating, we have done an episode on that. It's called why do you feel so tired after a big meal? So I guess there's a little bit of that. Maybe it's not about the kids, it's about the parents.

B (10:29)

Indeed. And then the other thing is, what is the exercise you're doing? So if it's extreme exercise and you're doing triathlon, people do expel food from their stomachs if they're eaten too close to it. And so, you know, you hear of brown emergencies in swimming pools when toddlers go into the pool. Well, this could be a yellow emergency or a multicoloured emergency.

A (10:56)

Yeah, fair enough. Please don't vomit in a pool, especially a public pool. Actually, no, just don't vomit in a pool if you can at all help it. I think that's probably a good piece of health advice.

B (11:05)

And if you have had a few wines for dinner, then stay out of the pool until you sober up.

A (11:09)

Right. And I think that that's something that's worth us putting a pretty fine point on, is maybe eating before swimming isn't really something that we should worry too much about. But there are definitely things that increase your risk of getting into trouble in the water. And alcohol and drug consumption is a big one.

B (11:25)

It is. Particularly in colder water. But in any water, your respiratory system doesn't work as well, your judgment isn't as good, and you lose heat, so you're more likely to become hypothermic.

A (11:38)

Okay. So I suppose it's as good a time as any to sort of recap on what we do know helps people keep safe around the water. Our Royal Life Saving Service doesn't mention eating before swimming as a risk factor, but it does warn people about not overestimating your swimming abilities or those of your loved ones, knowing the conditions supervising children and yes, avoiding alcohol around the water and of course swimming at patrolled beaches between the flags. And avoid swimming alone if you can help it because if if by some situation you do end up in trouble, you've got to have someone there to to yank you out if you need it.

B (12:14)

Yeah, swim between the flags and don't overestimate really important and learn to pick where the rips are.

A (12:19)

Indeed. Swim safely folks. Don't worry so much about what you're eating but definitely always take care around the water. And thank you Sarah for the question. You can always send your questions to thatrashbc.net au we love answering them.

B (12:33)

Now here's really important news. We are going back to Brisbane for the World Science Festival this year. Yes, tickets are on sale from Thursday 29th January. Come in, get in fast because they sold out fast last year. The date is Saturday 28th March this year and it's on from 3 o' clock to 4 o'. Clock. What more important thing have you got to do on Saturday 28th March than come along and listen or put in the questions that are going to be answered at that show.

A (13:03)

Yeah, we want your help choosing what we're going to talk about at the event so you can email thatrashbc.netau put World Science Festival Brisbane in the subject line and maybe we will answer your question with you in the audience. What a treat.

B (13:17)

But you've got to buy the tickets from the World Science Festival, not us.

A (13:20)

You do. Tickets are on sale tomorrow, Thursday 29th of January via the World Science Festival website.

B (13:26)

See you in Brisbane. And we'll see you next week as well.

A (13:28)

See you then.