High Intensity Interval Training: Increase Exercise Intensity To Lengthen Healthspan

Exercise Now, Stay Fit Later

The next few studies were about the effects of creatine supplementation and resistance training in aging adults. We know that aging decreases bone density as well as muscle strength while increasing fat deposition. Working out can prevent this, and the fitter you are when you are younger, the easier it is to be fit when you are older. Not only does midlife fitness improve later life fitness but also improves later life cognition. When looking at resistance training, what we want to do is train with heavy weight to get the most out of the workout. Heavy weights not only increase strength gains greater than repeated sets of light weights, but also have better implications for bone deposition, muscle tone, and blood flow.

When doing resistance work it is important to always go to exhaustion – sets and reps aren’t quite as important as they once were, strength and lasting change can only be done when muscles are worked to the point they can’t work anymore. The best way to do this is to do a “drop weight” style workout; lift heavy weight until you can’t lift that weight anymore, drop it and quickly pick up a lighter weight and keep going. When combined with creatine (supplies energy to the muscle by increasing the amount of ATP available), resistance training increases the muscle size by five percent. In seniors, because protein synthesis decreases, they need to consume more creatine to achieve the same benefits. The heavier, more difficult the work, the better the outcomes, in both strength and cognition (vigorous, high intensity 1

exercise seems to have the greatest benefit).

Take away To ensure that you stay healthy as you age, continue to workout, supplement with creatine to build muscles (increase consumption as you get older), resistance train with heavy weight and go until fatigue. The earlier in life you are in shape and the longer you stay in shape, the better the outcomes are for later life. The best way to exercise is through HIIT, which not only improves muscle strength but cognition too.

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Can Interval Training Help Mitigate Obesity?

The next few studies were about the effects of creatine supplementation and resistance training in aging adults. We know that aging decreases bone density as well as muscle strength while increasing fat deposition. Working out can prevent this, and the fitter you are when you are younger, the easier it is to be fit when you are older. Not only does midlife fitness improve later life fitness but also improves later life cognition. When looking at resistance training, what we want to do is train with heavy weight to get the most out of the workout. Heavy weights not only increase strength gains greater than repeated sets of light weights, but also have better implications for bone deposition, muscle tone, and blood flow.

When doing resistance work it is important to always go to exhaustion – sets and reps aren’t quite as important as they once were, strength and lasting change can only be done when muscles are worked to the point they can’t work anymore. The best way to do this is to do a “drop weight” style workout; lift heavy weight until you can’t lift that weight anymore, drop it and quickly pick up a lighter weight and keep going. When combined with creatine (supplies energy to the muscle by increasing the amount of ATP available), resistance training increases the muscle size by five percent. In seniors, because protein synthesis decreases, they need to consume more creatine to achieve the same benefits. The heavier, more difficult the work, the better the outcomes, in both strength and cognition (vigorous, high intensity 3

This session really just was in addition to all of the information we’ve already seen at the conference so far. Interval training is very important to health and can increase the palatability of exercise. The first study conducted a perceived exertion and ranked enjoyment test on continuous versus interval exercise when matched for VO2 Max. The researchers found that at 85% VO2 Max, 6 x 3 minutes with 30 seconds rest as intervals (or what they called micropauses between runs) was far more palatable than 18 minutes of continuous exercise, making it more likely to be followed as an exercise regime outside of the study.

A similar study about the palatability of interval training in obese individuals was done by the next presenters. We know that exercise is a struggle for most people, and making it palatable to obese people can be even more of an uphill battle. HIIT, as the researchers explained, is an excellent way to promote not only palatable exercise, but also can be used to alleviate some of the problems caused by obesity.

Periodized cycling improved peak power output with an unchanged VO2 Max, which meant that the obese individuals were improving their mitochondrial efficiency (they were better able to utilize glucose as a fuel source) as well as hinting at improved mitochondrial biogenesis. The researchers said, however, that the effects of interval training only last 24 hours, after which measures of health return to baseline. Thus, interval exercise needs to be done frequently if it is to be used as a way to mitigate some of the symptoms of obesity.

Take away Interval raining increases palatability of exercise and can be used to improve mitochondrial efficiency in obese individuals.

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Combat Heart Problems and Diabetes with HIIT

Exercise can be used to treat (if not cure) type 2 diabetes mellitus. We know from past studies that endurance exercise can increase insulin sensitivity up to three times it normally is in a diabetic person, as well, strength training seems to improve insulin sensitivity (to a lesser extent mind you). However, if you stop for as little as five days we lose all the benefits we have gained and we are back to square one.

Reducing Risk This can be a challenging if not outright daunting proposition to people who want to use exercise to help control their diabetes – exercise is time consuming and if we stop for even a little bit (we go on vacation or get injured or life just gets in the way) we lose everything we’ve worked for; it can seem like a waste to some, especially these at risk populations.

We might be able to use HIIT as a means of lessening the stress of extended exercise.

HIIT can be used to achieve many of the benefits of MICT in 25% or less of the time. The researchers found that an acute HIIT bout could decrease plasma glucose and deplete glycogen reserves (thus showing improved insulin sensitivity) by an average of 27% across 5

all type 2 diabetes patients, and brought their insulin sensitivity parameters back down to baseline.

What the researchers found as the mechanism was that intense training increased the cycling of glycogen better than any other forms of exercise (MICT or resistance training). The increased usage of glycogen and the demand to store more means that the insulin sensitivity is brought back up and glucose is used preferentially, something not seen in untreated type 2 diabetes.

Take away Type 2 diabetes can be controlled with bouts of intense exercise. HIIT increases the cycling of glycogen (improving insulin sensitivity) better than either MICT or resistance training in less than a quarter of the time it would take to otherwise perform the activity.

The final talk in the session discussed the usage of HIIT in people with heart problems (namely, is it a viable strategy). We’ve seen that HIIT increases heart rate greater than moderate exercise (puts more strain on the heart) which could potentially be dangerous for people with heart problems (or recent transplant recipients). However, a recent meta-analysis showed that there was little difference in heart strain between MICT and HIIT; peak heart rate was similar between the two which may be why no difference in cardiac event occurrence was seen.

Why exercise is important for heart patients is because it promotes not only greater blood flow, but also increases the drive for the body to create new blood vessels, which can bypass old and damaged vessels. We know HIIT takes less time and can be just as safe as MICT, so it should stand to reason that patients would gravitate more towards HIIT would it not? In reality there is a huge disconnect between what doctors prescribe as optimal heart rate output and what patients actually work at when in recovery. As well, the lasting perception that HIIT may be more dangerous than MICT that could be acting as a mental block preventing some patients from attempting to use HIIT.

Going Further Exercise is an excellent way to help heal people who have had heart issues or surgery to improve blood flow and promote the growth of new blood vessels. HIIT is proven to be just as safe as MICT and has many advantages over MICT because of the short duration but still is not used by patients because it is perceived to be dangerous. Tracking of heart rate output in patients should be used to ensure that patients are working at optimal output to improve recovery.

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Quick Facts For A Healthier You

Each day between the morning and afternoon sessions of the conference there was a two hour period of mini presentations. These were short, two-minute talks given by people who just wanted to present their research (they were not necessarily invited speakers). These rapid-fire talks came fast. Some were familiar as they had been presented through the conference, but I tried to get as many nuggets from them as I could.

I’ve written the more interesting points from the talks down in point form for you below: • Exercise can be used to prevent mild cognitive impairment (MCI). This is because it promotes blood flow, increases white matter integrity (brain matter), and decreases the amount of amyloid-beta (which causes amyloid plaquest that causes Alzheimer’s Disease) in the cerebrospinal fluid.

• Alzheimer’s Disease patients have a much higher cost of exercise (mitochondria deficit) and have much lower rates of oxygen consumption. Six months of exercise training can improve vascular health and reduce the cost of walking and improve mitochondrial functioning in Alzheimer’s patients.

• Dynamic treadmill training (walking on a treadmill that is moving up/down or rolling side to side as the belt moves) greatly reduces the gait sway of people who suffer from Parkinson’s disease. While it does not seem to improve static motor control, it seems to 7

improve dynamic muscle control (standing vs walking).

• Subjecting humans to a water maze similar what researchers subject rodents to (a special learning task) can significantly improve cognitive test scores. As well, humans and rodents search for the in-water platform in much the same way, going directly for where platform last was and fanning out from there.

• In elder care, the more the seniors are subjected to different sensory profiles, the better the long-term outlook is for the quality of life and health. This means more exercise, more communication, longer duration of activities and greater intensity of activities.

• Yoga significantly improves the autonomic nervous system in people 60 and over. We are not consciously in control of this system. Thus, the more it is done, the better the control (measured through incontinence events).

• Older patients who do resistance training improved their redox status. This is similar to antioxidants, which removes harmful, cancer causing substrates in the body. Furthermore, they experienced improved function of these redox reactions that can create the harmful substrates.

• Overdoing it on antioxidants can lead to poor reaction to oxidative stress. This happens especially in response to exercise. Thus, you need some oxidative stress to kick-start the benefits you get when you exercise.

• High load/HIIT seems to decrease the chance of muscle atrophy and disuse issues (frailty) greater than any other forms of exercise.

• HIIT makes exercise more tolerable to get into hypoxic states. When your body is deprived of oxygen it’s working hard.

• Training just arms or legs, or one arm and one leg can increase the oxygen capacity to work in whole body/cross limbs. This is why it is important to keep exercising when you are injured or have a broken limb.

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90 Seconds A Day of HIIT Might Be All You Need

We know that HIIT can be used to improve parameters of health in diseased individuals, but can it work in healthy individuals/a whole population, and if so, how might it work?

The first talk of the session examined just that by having individuals perform single leg cycling tests; one leg would perform short, higher intensity intervals (4 x 5 minutes at 65% of max wattage) and the other leg would perform longer, continuous exercises ( 30 minutes at 50% max wattage).

Biopsies from each leg were taken and analyzed, as well, whole body measures were taken during each exercise protocol to see how the body changed when stressed differently.

90 Seconds A Day Study Legs that underwent HIIT showed increases in mitochondrial protein markers greater than moderate intensity continuous training (MICT) in the whole muscle but did not lead to 9

changes in muscle fibre type (type I being slow and type II being fast twitch).

On a whole body level HIIT led to an increased heart rate and increased amount of lactate production (a by-product of working harder).

The researchers wanted to push the workload even shorter and see if the effects of HIIT were still beneficial. They had participants conduct a specific workout: Two minute warm up + 30 second work + two minute rest + 30 second work + two minute rest + 30 second work + three minute cool down, three times a week.

Work was done at 86% of the participants’ max heart rate.

So can less than 15 minutes of exercise (90 seconds of total hard work) three times a week translate to better health outcomes even when compared to continuous?

The results seem to indicate so; as little at 90 seconds of hard work resulted in a 19% increase in VO2 Max (in regular, non-elite individuals) over the MICT comparison group, there was an increase in insulin sensitivity that was on par with the MICT group as well as matched increases in stroke volume and cardiac output.

The only area where MICT was better than this HIIT protocol was in body composition where small but significant changes to muscle mass and body fat percentages were noted in the MICT group that were not seen in the HIIT group.

So, form a pure metabolic health standpoint it would seem that HIIT is a viable alternative to improving population health, which goes in the face of most public health models of exercise that calls for moderate continuous exercise. Less work can be used to get the same health outcomes which is great news for people who don’t have the time for or are easily discouraged by longer bouts of exercise.

Take Away: As little as 90 seconds of really hard work, three times a week can be just as beneficial for metabolic health as longer continuous exercise.

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