Science on high intensity interval training: HIIT, or SHIIT?

Let me pose you a question: would you rather go down to the video store (if it hasn’t yet gone bankrupt) to hire a DVD, or stream it from the comfort of your own home? You’ve probably answered: the comfort of your own home, unless of course you get all nostalgic about walking down the street to hire discs. I know I do!

Okay, okay, now let me pose you a further question: would you rather spend one hour exercising, or 30 minutes? Stop, don’t answer that just yet. What if I were to say that both workouts would give you equivalent results? Unless you’re a time wasting enthusiast, pain junky, or DOMS devotee you’re probably going to answer 30 minutes. Well a new (old) exercise regiment known as high intensity interval training (HIIT) is offering just that.

Yes, if you believe one of the internet’s many great fitness prophets, then you will be aware that HIIT is the shit! Slow endurance training is the DVD for hire and HIIT is Netflix, which is of course, the shit. So is HIIT truly the shit, or should you beware of false fitness prophets?

What is HIIT?

Before I answer your previous question. What is HIIT? Simply put, HIIT involves performing intervals of highly intense exercise followed by either complete rest, or low intensity exercise. The high intensity-low intensity combination seems to be the more popular of the two currently.

How about an example? Sure, here’s one. Let’s say running is your game. Your HIIT may involve a ratio of a one minute sprint, to 45 seconds of slow jogging, repeated for a total of 15 minutes. It certainly doesn’t have to follow this exact ratio, or duration and these variables change greatly from protocol to protocol, that was simply an example. I should note, however, that scientific data to date has found minimal difference between different interval ratios thus far (9).




Why HIIT might be the shit?

HIIT is proposed to lead to multiple complex physiological changes to the skeletal muscle system that promote fat burning efficiency and preference, and more efficient oxygen utilisation. In turn, this is proposed to: make you skinnier, fitter and it will likely give you the ability to fly! But probably not the last one.

Science and HIIT (SHIIT):

Of course theory means little unless it translates to real world, real life changes. So, does it? Spoiler, it generally does.

Aerobic health:

A review paper analysing studies on individuals suffering from various different lifestyle diseases found HIIT to be effective. Specifically, cardiovascular fitness, as measured by Vo2 max, was 9% higher when individuals performed HIIT as opposed to moderate intensity continuous exercise (1). Another large scale review paper on scientific studies to date found HIIT to improve: aerobic fitness level more so than normal, moderate intensity exercise in both sedentary and active individuals. But it was only as effective as continuous exercise training in athletic persons (2). If that wasn’t enough science for you, a third study found HIIT to improve aerobic fitness as well as moderate intensity continuous exercise in a relatively fit group of people (3). This basically tells us that the lower your fitness level is, the better you will respond to HIIT and if you only want to do one sort of training, HIIT will be more effective than continuous training for aerobic fitness. Conversely, if you’re really fit and only want to do one form of exercise, then HIIT is as good as continuous moderate intensity exercise for aerobic fitness.

Muscles, muscles, muscles:

What about those muscles? Can you skip the separate weight sessions and do an all in one HIIT session? Well, the scientific data is very limited on this. But the one study that does exist on this topic, found that when having an active rest period was compared to having complete rest, complete rest won. Yes, complete rest led to greater work output, which in turn would likely mean improved: muscle mass, strength, power, looking shredded bro (4)! This makes sense and says that resistance training HIIT will likely provide you with some nice adaptations, but not as good as traditional weight training where proper rest between sets is taken.

Weight loss:

What about weight loss then? The data ain’t crystal clear on this. One study found HIIT boxing was better than continuous brisk walking at improving body fat percentage (5). Another study found participants had a decreased waist circumference following HIIT, but not following moderate intensity continuous exercise (6). Yet, in complete contrast, continuous moderate intensity exercise was found to decrease trunk fat more so than HIIT in another study (7). All in all, the science isn’t certain on whether HIIT or continuous training is best for weight loss. But if you base your workout on the number of calories you’re burning, based on average heart rate or a similar method, then you should be no worse off than performing continuous exercise, as average heart rate tends to be higher for HIIT and stays elevated for longer following exercise.

Adherence:

If HIIT is quicker to do, then you’d think people would do it more and stick to it. And they do! High intensity interval training led to a greater level of adherence (89% vs 71%) than moderate intensity continuous training (8). Grouse!

Is it healthful? 

Ladies and gentlemen, HIIT is the shit! Or at least it is pretty darn good and very relevant to our time-centric society:

• HIIT is likely as good as endurance exercise for aerobic fitness and if you’re of a low fitness level it’s probably better.
  
  
•  Resistance training HIIT won’t get you as ripped as traditional resistance training with structured rest periods. But it’s probably not a great deal worse.
  
  
• HIIT will lead to at least equivalent weight loss to continuous moderate intensity exercise in a shorter period of time, likely due to an elevated average heart rate.
  
  
• HIIT generally leads to higher adherence, so you’re more likely to stick with it.

Our verdict :Highly healthfull. If you’re time poor and unfit, HIIT’s the most effective way to turn things around. Although if time is less of a factor and you really want to optimise your health you should combine HIIT, anaerobic exercise and aerobic exercise as part of a proper periodised program. Especially, if you have sport related goals.

I hope this has been healthful!

Isithealthful

I hold a Doctor of Physiotherapy, Bachelor of Exercise Science and am a qualified personal trainer. I have extensive clinical and research experience and a strong passion for all things health. This has driven me to write the blog: Is it healthful, in order to analyse sound scientific research to determine if a product, service or intervention is healthful, or simply a waste of money or time.

 
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Trees and plants can feel stress, need time to recharge like humans

KEPONG: Trees feel stress and need rest the same way humans do, and the Forest Research Institute of Malaysia (FRIM) is playing doctor to keep them healthy.

FRIM director-general Datuk Dr Abdul Latif Mohmod said trees in the cities were the worst affected.

“It causes them to fall sick, making them susceptible to attacks from fungi and pests,” he said at the institute’s open day and World Environment Day yesterday.

He said a tree that looked healthy on the outside could be hollow inside, making it hard to diagnose its problem with the naked eye.

Dr Latif said FRIM used sonar technology as an “X-ray” machine to diagnose such trees.

Research officer Ahmad Aza­ruddin Mohd Noor demonstrated the use of the device called the Picus Sonic Tomography.

“The device generates a 3D image of a tree’s insides, effectively identifying decay and cavities in the trunk,” said Ahmad Azaruddin, a certified arborist (professional in cultivating, managing and the study of trees) who has helped local councils manage trees.

“A tree that has become 30% hollow can fall in the event of a thunderstorm. If that happens, it can be very dangerous,” he said.

To prevent this, his team would usually prune it to preserve its structural integrity.

He said the team would do its best to preserve a tree due to its benefits to the urban ecosystem.

“We will be forced to cut it down only if the damage is too severe,” he said, adding that less than 20% of trees faced such a problem.

“In the cities, it only happens to trees that are more than 100 years old or those with roots that have been damaged.

“In the forests, the usual culprits are termites,” he said.

Dr Latif said as trees feel stress, FRIM closes its canopy walkway on Mondays and Fridays to let them rest.

“Our canopy walkway can accommodate 200 visitors a day. We don’t want to give the trees too much stress,” he said.

He also said Malaysians should be proud of FRIM’s man-made tropical forest as it was the world’s largest and oldest.

The forest covers seven arboreta (repositories of living plants) and a botanic garden.

He said it was originally an abandoned mining land and that the Forestry Department, which owned less than a hectare of it, planted its first tree there in 1923.

“Today, it spans 544.3ha and houses 73 out of 92 critically endangered plants in Malaysia,” he said, adding that more than 1.3 million people visited FRIM last year.

Dr Latif said FRIM prided itself as a community-friendly institute that facilitated learning and embraced outstanding universal values.

“Because of this, we are working towards being gazetted as a Unesco World Heritage site by 2020.”

By Adrian Chan The Star/Asia News Network

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• Restoring Mother Earth

One to call their own: Residents and families posing with a tree they just planted for the programme. The particular tree will remain as part of each family’s responsibility and heritage in USJ Heights, inherited by future generations.

South Korea declares war on MERS

A family of tourists wearing face masks stand on a street in the popular Myeongdong shopping area in Seoul, on June 4, 2015 (AFP Photo/Ed Jones) 

Seoul (AFP) - South Korea reported on Friday a fourth death from Middle East Respiratory Syndrome (MERS), as an infected doctor fuelled fears of a fresh surge in cases and prompted Seoul's mayor to declare "war" on the virus.

Five new cases overnight took the number of infected people to 41 in what has become the largest MERS outbreak outside Saudi Arabia, with close to 2,000 people in quarantine or under observation.

The latest fatality was a 76-year-old male patient who died Thursday after testing positive for the virus on May 21.

Criticised for its lack of transparency in addressing the health scare, the Health Ministry finally confirmed the name of the hospital where the first patient to be diagnosed with MERS was treated.

The ministry said anyone who had visited the hospital in Pyeongtaek, about 65 kilometres (40 miles) south of Seoul, between May 15-29 should report to a clinic for screening.

The government had initially declined to name any hospitals treating cases of MERS, for which there is no vaccine or cure, arguing it could cause them unfair commercial losses.

- Infected doctor fuels fears -

View gallery

Seoul's Mayor, Park Won-Soon, pictured in May 2014 (AFP Photo/Ed Jones) >>

Of particular concern was the positive test of a doctor at a major Seoul hospital who was understood to have taken part in public meetings attended by up to 1,500 people while infectious.

Seoul Mayor Park Won-Soon criticised the government for not sharing information about the doctor's movements, and said his administration would take the lead in ensuring public safety.

"From now on, Seoul city is embarking on a war against MERS. We will take swift and stern measures... to protect the lives and safety of our citizens," Park told reporters Friday.

Health Minister Moon Hyong-Pyo apologised for the public anxiety caused by the outbreak, but rejected Park's criticisms, saying the mayor was encouraging "mistrust and misunderstanding".

The government had been handling the doctor's case carefully to avoid public panic, Moon added.

More than 1,000 schools, from kindergartens to colleges, have temporarily shut down across the country, while the government's MERS hotline has been taking thousands of calls a day.

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Tourists wearing face masks look at a map in the popular Myeongdong shopping area in Seoul, on June  …>>

According to the World Health Organisation (WHO) MERS has now infected 1,179 people globally, with 442 deaths. More than 20 countries have been affected, with most cases in Saudi Arabia.

The virus is considered a deadlier but less infectious cousin of Severe Acute Respiratory Syndrome (SARS), which killed hundreds of people when it appeared in Asia in 2003.

- Possible mutation? -

The WHO has said it expects more infections in South Korea, while stressing there was currently "no evidence of sustained transmission in the community".

A health ministry statement said a WHO team would visit next week, citing concerns that the virus has been showing a "slightly different" pattern from the one detected in Middle East.

"We have yet to determine whether there has been any mutation," said Choi Bo-Yul, the head of a civilian task force set up to help with the outbreak.

Among the recent infections was an Korean Air Force chief master sergeant, who represented the first MERS case among members of the military.

The airman is serving at the air base in Osan, south of Seoul, which also hosts the US 51st Fighter Wing.

In a message to base personnel, the fighter unit's chief medical officer, Colonel Krystal Murphy, said around 100 people who had been in contact with the infected man had been asked to remain at home.

"We recommend everyone exercise caution and use good hygiene practices to prevent any further spread," Myers said.

A large number of public events have been cancelled and organisers of the World Student Games in the southwestern city of Gwangju next month admitted they were "very anxious."

"No country has cancelled so far, but obviously we're keeping a close eye on what is a worrying situation and hope it will come under control soon," an official with the Universiade's organising committee told AFP.

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5. South Korea reports five more cases of MERS, raising total to 35 Reuters