Bikram yoga: worth the heat?


Is knotting yourself into a pretzel in a hot room better for you than trying the same thing at room temperature? A recent paper (featuring in the Express, Forbes & the Independent) asked that very question. This study was fairly well reported, with all three of the above news outlets choosing headlines that accurately reflected the research – good stuff! So with that in mind let’s take a look at the study.

Yoga comes in many shapes and sizes but this study focused on a style of yoga called Bikram yoga. Bikram, who’s founder has been in the headlines for some fairly unsavory accusations of late, follows the same strict series of 26 yoga poses at the nice and toasty temperature of 40.5ºC.

A previous study by the same group of scientists found that for people aged 40-60, 9 weeks of Bikram yoga improved how well endothelial cells worked (these are the cells that line the inside of your blood vessels, known to be involved in vascular diseases such as atherosclerosis). So this time the team wanted to work out whether these changes were due to the yoga, the heat it was done at or both.

To figure this out, participants were randomly assigned to either practice Bikram yoga 3 times a week for 12 weeks at the usual 40.5ºC, to do the same sequence at a more pleasant 23ºC or to do no yoga at all (the control group).

So how reliable is this research? Let’s check it out using our toolkit.

  1. The study was published in the peer-reviewed Experimental Physiology and the news articles above have accurate headlines and summaries of the research (Forbes get extra kudos for getting a quote from an independent researcher).
  2. The press release however fails to mention that the study only included 40-60 year olds, and according to the groups’ previous study the same effect just isn’t there for younger participants (sorry folks!)
  3. An obvious downside to studies like this is that all participants are obviously well aware of whether they are practicing yoga or not! This means that some measurements could be affected by the placebo effect. Though this is less likely for a study like this where results were drawn from X-ray scans and blood tests, as opposed to questionnaires of perceived pain for example, the researchers doing the measurements weren’t blinded (they knew what group each participant was in) meaning that some bias could have snuck into the data analysis.
    This is why a randomised double blind placebo-controlled trial is considered the ‘gold standard’ (double blind = neither the participant nor the researcher know which treatment or intervention the subject is receiving).
  4. It is worth considering that this study has shown an effect in only one type of yoga – in fact a previous study by the same group didn’t see any changes in vascular function when practicing hatha yoga twice a week, so is it that the Bikram yoga was practiced 3 times a week or is it the type of yoga? It’s very difficult to say.

To better understand whether yoga is beneficial or not overall, collecting many different studies together to look at all the available evidence is probably the best indicator. The Cochrane Library review and summarise all of the evidence that has been collected on a given treatment for a particular illness or benefit, from how to get kids to eat more fruit and veg to yoga for improving health and wellbeing.

Overall this study throws some more evidence into the ring that some types of yoga can be good for some people, sometimes.

A Dhal Won’t Stop Dementia

Curry dementia

Today the Daily Express leads with this headline: Eat CURRY to beat Alzheimer’s: THIS spice boosts memory and may stop onset of dementia.

Now it’s safe to say I am sceptical of this. Curcumin, found in turmeric (hence the link to the curry) is a real trigger-point with many scientists as, despite countless suggestions in the headlines that it can be a miracle cure for almost anything that ails you (Alzheimer’s, cancer and lupus all in 2018…), there is currently no evidence of any effect in humans (see this useful blog for a summary). “But why not at least try it? What’s the harm?”. Well unfortunately curcumin has the unenviable history of actually killing someone due to unregulated use. So I’m on the back foot with this already but it’s important to look through this article nonetheless, let’s break it down using the HYH toolkit.

  1. The title is indeed outrageous. People living with dementia were not tested at all and there is no way they can make these claims. Additionally, no-one was given any curry. They were given a pill containing curcumin which is a substance that is in an ingredient that is in curry. Making this link is false.
  2. Reading further things look up. The research has been published (but there is no link) in a reputable journal and it does appear to be open-access. Thumbs up.
  3. The study is well-designed. The trial (done in humans ) included randomisation and blinding and the discussion section of the paper includes a healthy segment on the (many) limitations of the study.
  4. There is a quote from an impartial source which provides an excellent voice of reason – pointing out that these are early-stage results and that no-one should be taking curcumin just yet.
  5. There is definitely an issue with correlation-causation. The paper essentially makes the statement. Indians eat curry. Indians are less likely to develop dementia. Therefore curry stops dementia. This is backed up by some weak studies with poor statistics and is a dangerous point to make.

As usual this is actually a fairly well-written article with a naff headline. Another classic hallmark is some excited quotes of how great the study is – by the lead author. One example is this “Studies indicate a lower prevalence of Alzheimer’s in Indian people who consume curcumin in curry.” – which is misleading as I point out in number 5 above.

Overall we can make the usual (but boring) conclusion – interesting study, more research needed. I’m going to give this a 4/10 (7/10 without the headline).

Do Our Brains Actually Communicate by WiFi?

Blog 1 Picture

Do our brains communicate via wifi? Image via DigitalRalph @Flick 

Does your brain work on fibre-optic or is it stuck in the dial-up era? A recent article posted by the Daily Mail (originally appearing in a fuller, pay-walled, form on the Sunday Telegraph) claims that we communicate in part through a wi-fi-like system between brains. Sound a bit too bizarre to be true? Well, that’s because it is not just an exaggeration but quite simply wrong.

As social creatures we pick up on a myriad of cues from others around us and use this information to guide how we respond to others in familiar or unfamiliar situations. It is this information, alongside our own prejudices and experience, which provides kindling for what we know as ‘gut feelings’. It is not, as the author of the above article suggests, because our brains work in a similar way to the router in your living room.

Besides the bizarre title, why should we be cautious about this article? Here are the first things which raised alarm bells in my head:

  1. The article only had a single expert (the same one who put the wi-fi idea forward) talk about the issue. This is not necessarily terrible practise but with bold claims you want to have a broad range of informed views to feel more confident in the article. If someone with no vested interest in the results can also support them, and provide evidence to back them up, then this should help quieten the initial pseudoscience claxons.


  1. The ‘evidence’ for the article’s claims are original thoughts of the researcher from their recent book. These claims are supported by research which does not appear directly linked to the points being made in the article.


  1. On the theme of evidence, the only support for the claims being made are in the form of a link to a pay-walled news story from another newspaper. No research to backup the claims of the researcher and the article makes it hard to determine whether what is being said is true and based on evidence.


  1. Sometimes ridiculous titles do a dis-service to a reasonably written article. This is not one of those times. This title is misleading and quite simply wrong.


  1. Finally, the author of the article failed to spell the researcher’s name correctly. Journalists (and most other people with jobs) have strict deadlines but the name of the researcher the piece is about should really be spelt right. It might seem like a minor point but if they can’t get the name of the most important person in the piece right, they likely did not research the topic in sufficient detail for any reader to comfortably trust on face value alone.