90-seconds of exercise (HIIT)

The WEEK reported (a few weeks ago) an article on the "90-second exercise routine". As with The WEEK it pulls on all the different British newspapers for its stories, I couldn't find the exact story which it had drawn upon or even find, by searching through PubMed, the original study or even the abstract but I did find a similar article from MNT (Medical News Today) (albeit slightly outdated and which may represent ideas which have since been investigated further and maybe even improved on/discarded so please take the dates of these articles into account when reading them)(http://www.medicalnewstoday.com/articles/242498.php).

The WEEK (Issue 902) (loosely taken from the Daily Mail)
"Scientists from the universities of Bath, Nottingham and Birmingham say that having warmed up for two minutes, people should engage in three, 30-second bursts of really intense exercise with 60-second rest periods in between. Results from an ongoing study involving hundreds of middle-aged people indicates that HIIT (High Intensity Interval Training) is just as effective as long sessions in the gym. The team isn't sure why this should be so, but notes that one advantage of HIIT is that it seems to suppress appetite; by contrast, longer workouts tend to leave people hungry."

However although this form of exercise known as HIIT sounds easily carried out, it has to be done properly for it to be effective. The 30-second bursts of high intensity workout should be something like "running up a flight of stairs or pedalling furiously on an exercise bike" (The WEEK (as above)) at almost maximum intensity.

For example "recent [be aware this report is from the 6th of March 2012] HIT research shows, that doing ten one-minute sprints on a stationary exercise bike with about one minute of rest in between, three times a week, is as good for improving muscle as many hours of less strenuous conventional long-term biking" (http://tinyurl.com/87mutke).

In a study a few years ago (by Gibala around 2010) "participants had to pedal at their maximum possible effort level on a specially adapted lab bike. The thinking then was that 'all out' was an important part of the HIT [High Interval Training (referring to the same style of training as HIIT)] method.

But then, in 2010, Gibala and colleagues published another study in The Journal of Physiology, where they showed how a less extreme form of HIT worked just as well for people whose doctors might be a bit worried about them adopting the 'all out' method, for instance those who might be older, less fit and overweight.

In that form of HIT, the workout was still beyond the comfort zone of most people (about 95% of maximal heart rate), but was only half of what might be regarded as an 'all out' sprint" (http://tinyurl.com/87mutke).

The BBC ran a Horizon episode on HIIT with someone (known as Mosley) doing a HIIT programme for 4 weeks to observe the health effects. His programme ran like this (from http://tinyurl.com/87mutke):
 

1.    First, you warm up for a couple of minutes with some gentle cycling: then you cycle as fast as you possibly can for 20 seconds.

2.    Cycle gently again for a couple of minutes while you catch your breath, then do another 20 seconds 'flat out'.

3.    Then, for a final time, two minutes gentle cycling to catch your breath, followed the third period of 20 seconds at 'full throttle'.

 

One of the health effects that the HIIT/HIT had on Mosley was on his insulin sensitivity...

 

"The researcher (Timmons) had tested Mosley for a number of health indices before he started, and then, after his 4 weeks of HIT, Mosley went back to the lab to be re-tested. A main test was for insulin sensitivity. When they measured Mosley's insulin sensitivity before he started his HIT exercise regime, the result showed he was just inside what would be regarded as healthy tolerance. Timmons told Mosley that research from a number of centers shows that doing 3 minutes HIT a week can improve insulin sensitivity by 24%. And this is exactly the amount by which Mosley's own index improved.

But bigger improvements than this have also been recorded, albeit with a slightly different HIT regime. A 2011 study by Gibala's group at McMaster published in Medicine & Science in Sports & Exercise found a 35% improvement in insulin sensitivity after only two weeks.

Insulin sensitivity is important for keeping blood sugar/glucose stable. It is not clear how HIT affects insulin sensitivity, but Timmons, and some other scientists that Mosley spoke to, suggest it could be because HIT uses many more muscles than conventional aerobic training. HIT engages 80% of the muscles of the body, compared to up to 40% during moderate jogging or cycling. HIT engages not only leg muscles, but also the muscles in the upper body, such as the arms and shoulders.

One of the effects of exercise is to break down glycogen in muscles. Glycogen is a stored form of glucose. The theory is that removing stores of glycogen makes way for fresh glucose to be deposited from the bloodstream. So the more muscle tissue that come under this influence, the more space that is available for new glucose deposits.
 
However there are some things that HIT will not necessarily do for you. For example, in Mosley's case, it didn't improve his aerobic fitness, the other main health index that Timmons and colleagues tested.

The evidence that ties aerobic fitness to health shows that one of the best predictors of a healthy long life is the body's ability to take in and use oxygen while we are exercising maximally. The more blood the heart pumps around the body, the more oxygen our muscles use and the lower our risk of disease and early death.

This idea stresses the idea that the more you do, does not necessarily mean the more you benefit.

What we are learning is that the link between exercise and health is an individual thing. Methods like HIT are useful, because very quickly, without spending a lot of time and effort, you can find out what works for you, and what doesn't, and fine-tune a program that you can fit more easily into your lifestyle." (http://tinyurl.com/87mutke).

For further information and the full stories visit:
http://www.medicalnewstoday.com/articles/242498.php
http://www.medicalnewstoday.com/articles/182165.php

Start to 2013

As it's recently been New Year and Christmas (and I haven't posted for a while!) I thought I'd do a story based on alcohol, and whilst we are having a post about alcohol, why not tie in smoking too.

The BBC reported on January 2nd that "alcohol calories 'too often ignored'"...."people watching their weight should pay closer attention to how much alcohol they drink since it is second only to fat in terms of calorie content [reported by World Cancer Research Fund (WCRF)]. Eating or drinking too many calories on a regular basis can lead to weight gain. Unlike food, alcoholic drinks have very little or no nutritional value" (http://www.bbc.co.uk/news/health-20874204).

An interesting calorie calculator was embedded in the report (http://tinyurl.com/aswlqvf) showing the number of calories consumed with certain drinks, how many chocolate digestive biscuits that equated to and then how many minutes of brisk walking it would take to walk off that number of calories. As an example 2 standard glasses of wine equates to 3 chocolate biscuits in terms of calorie content and 52 minutes of brisk walking to burn those 248 calories off.

I also found an abstract for a study entitled "Alcohol consumption, nutrient intake and relative body weight among US adults" at (http://ajcn.nutrition.org/content/42/2/289.abstract). The study showed that  "drinkers had significantly higher intakes of total calories than non-drinkers, but only because of their intakes of alcoholic calories. Among drinkers, the intakes of non-alcoholic calories decreased as alcohol intakes increased, and it was estimated that between 15 and 41% of the alcoholic calories replaced non-alcoholic calories. Despite their higher caloric intakes, drinkers were not more obese than non-drinkers." It was therefore "suggested that alcoholic calories may be less efficiently utilized than non-alcoholic calories, or may interfere with utilization of non-alcoholic calories."

The smoking story was about research (carried out by the universities of Oxford, Cambridge and Kings College London) that challenged the "widely held belief that giving up smoking makes you more edgy and that smoking [itself] relieves stress". The story was run on the BBC, Medical News Today and also in The WEEK (Issue 902). On the Medical News Today website (http://www.medicalnewstoday.com/articles/254544.php) the following quote from researchers on the project was used. The researchers wrote:

 

"The belief that smoking is stress relieving is pervasive, but almost certainly wrong. The reverse is true: smoking is probably anxiogenic (causes anxiety) and smokers deserve to know this and understand how their own experience may be misleading."

 

"The researchers recruited 491 smokers who attended NHS smoking clinics, and tested their anxiety levels...when their anxiety levels were tested again, the quitters were found to have reduced their anxiety by nine points on average, whereas those who had failed to quit were feeling more anxious: their levels had increased three points" (The WEEK).

 

"The decrease in anxiety was particularly noticeable among the ex-smokers who used to smoke "to cope", compared to those who used to smoke "for pleasure" (Medical News Today article: above).

 

The researchers concluded saying "stopping smoking probably reduces anxiety and the effect is probably larger in those who have a psychiatric disorder and who smoke to cope with stress" (MNT article).




 

Sports Drinks

I found an article about sports drinks in THE WEEK 4th August 2012.

The article ran like this:

"The sports drink market is worth £1bn a year in Britain. But according to an article in the British Medical Journal, in most cases, people would do just as well, if not better, to drink water. The review of 104 popular brands found that although manufacturers make many grand claims for the effectiveness of their often calorie-laden drinks - whether in boosting performance or aiding recovery - there is a "striking lack of evidence" to back up most of them.

For instance, Lucozade Sport, the UK's bestselling sports drink, is said to have "an isotonic performance fuel to make you faster, stronger, for longer". But when Dr Carl Heneghan, director of the University of Oxford's Centre for Evidence-Based Medicine asked manufacturer GlaxoSmithKlise (GSK) if they could assess the research on which these claims rest, he was given what scientists call a "data dump" - 40 years' worth of research which included 176 studies. His team managed to examine 101, before concluding that "the quality of the evidence is poor, the size of the effect is often minuscule and it certainly doesn't apply to the population at large who are buying these products". They were similarly sceptical about claims that branched-chain amino acids - found in some of GSK's protein drinks - can enhance performance and recovery. One nutrition expert, Professor Mike Lean of the University of Glasgow, described the evidence for amino acids improving muscle strength as "absolute fringe", and in any case "totally irrelevant" in the context.However, GSK stands by it's claims, which it insists are backed up by science."

This article seems to play down the use of sports drinks branding them as a waste of money because there is no proof of their ability to increase performance or aid recovery. I then dug around in PubMed and on the BMJ to try to find some of the research papers where the data had come from and found this: http://tinyurl.com/cyzt7lp, a paper talking about the birth of sports drinks their use because of dehydration rather than thirst.

"The researchers also contend that much of the science behind sports drinks is biased or inconclusive and that empty calories from sports drinks are major contributors to childhood obesity and tooth decay" (http://tinyurl.com/coye356). So here we can see that there societal issues to do with the consumption of these drinks, although how many would one have to drink to lead to childhood obesity?

A BMJ article states that "Healthcare professionals should be encouraged to talk with patients about the calorific content of SSBs [sugar sweetened beverages] when discussing lifestyle modification to manage overweight and/or obesity . . . Consumption of water in preference to other beverages should be highlighted as a simple step towards healthier hydration: recommending 1.5 to 2 litres of water daily is the simplest and healthiest hydration advice you can give.” (http://www.bmj.com/content/343/bmj.d4280) So this article also agrees with the obesity issue arising from the consumption of sports drinks.

However I think that the killer argument came from the BMJ when Powerade were quoted on their website saying “water doesn’t have the performance benefits of a sports drink,”—but it does not go on to quantify what those benefits are" (http://tinyurl.com/cyzt7lp).

If you read the BMJ article (http://tinyurl.com/cyzt7lp then you can make up your own mind based on the evidence/lack of evidence of whether they actually are beneficial..?!
 

Worldwide Flu Pandemic?

Another article from the New Scientist website that I found was looking into this question; "Two labs have made lethal, highly transmissible versions of bird flu virus – do the risks of it escaping outweigh the benefits of the research?" (http://tinyurl.com/7q74mgz). The labs have "brewed up variants of H5N1 that can spread between ferrets merely breathing the same air" (http://tinyurl.com/7q74mgz) which shows that this is an extremely contagious virus that could most certainly cause a pandemic in human beings.

I found out about the H5N1 virus, Avian Influenza, on PubMed Health (The World's Largest Medical Library). Avian Influenza is a "flu infection in birds; the virus that causes the infection in birds can mutate to infect humans, such mutation could start a deadly worldwide epidemic" (http://tinyurl.com/3hcyygv). People have been infected with the virus all across the world and "slightly more than 60% of those who became ill have died" (http://tinyurl.com/3hcyygv). This is a staggering statistic, which was also hinted by D. A. Henderson of the University of Pittsburgh, Pennsylvania who said that the "1918 flu would look like nothing if this really got loose." To give a scale to his words, he is referring to the epidemic "known as 'Spanish Flu' or 'La Grippe' between 1918-1919 which killed between 20 and 40 million people" (http://virus.stanford.edu/uda/).

In 2004 the H5N1 virus "caused poultry disease in eight Asian countries and infected at least 44 people, killing 32, most of these people had close contact with poultry" (http://tinyurl.com/7maqhxz). This shows that there are recent examples of the severity of this flu. New Scientist say that they "don't know for sure that the viruses would behave the same way in people as in ferrets [indicated in the aforementioned experiment], but the assumption has to be that they do" (http://tinyurl.com/7q74mgz). However on another website, http://tinyurl.com/7maqhxz, it is suggested that "the virus does not easily transmit from human to human" due to the binding properties of the H5N1 virus.

I think, based on the theories of the biologists and the conflicting views on how effectively the virus will take hold in humans, that we need to be aware that there is a serious risk associated with laboratories manufacturing and testing this virus and that maybe there should be limited access for those those who are working on the virus, so as to reduce the chances of passing it on. Maybe the scientists should live on a campus where they are isolated from others while they are experimenting on the virus. So in answer to New Scientist's question; "do the risks of it escaping outweigh the benefits of the research?" I would say that yes, it is worth the research so we can learn more about mutations and viruses but there needs to be strict regulations and monitoring in place to deal with the risk of a pandemic.