Mind Body Evolution Podcast

Interval Training

Interval training is able to provide the benefits of exercise in a very short time by briefly exceeding the body's maximum output.

Dr. Josh Stout, PhD

Nov 17, 2023 — 14 min read

The Fastest Easiest Way to Get the Benefits of Exercise

Please scroll down for links below the transcript. This is lightly edited AI generated transcript and there may be errors.

Dr. Josh Stout 0:10

Hello, this is Dr. Stout. It's November 16th, and I would like to talk about interval training.

So I've been doing these shorter sessions that are more related directly to physiology and health instead of simply doing more imagination or mythology related discussions. All of this I'm trying to relate to human evolution, but there's different sides of it. That's why it's mind and body.

So today we're just talking about the benefits of interval training as essentially one of the magic bullets that we have for our health. So much like intermittent fasting without too much effort can cause tremendous benefits, particularly to insulin sensitivity. Interval training also has similar benefits, so interval training is short bursts of intense exercise within a lower intensity workout.

So you do a 30 seconds or a minute of very high intensity work followed by 30 seconds or a minute or even 2 minutes of resting. And then you do it again and you see you do this several times for a total of 20 minutes or half an hour, and that's interval training.

And it matches the activity of what hunter gatherers would have done walking long distances and then digging for a few minutes and then walking some more and then digging for a few minutes or running really fast to get to a kill site, cutting off some of the muscle and then running back with it, and then the rest of the day sitting around and trying to conserve energy.

These activities appear to show similar benefits to longer and more strenuous exercise. One study did 30 seconds of intense cycling, followed by 4 minutes of rest for a 20 minute routine and a total of six sessions of 15 minutes of exercise per two weeks and showed a significant benefit over a six week period. This approach showed similar results to typical endurance regime, despite being 90% less exercise and 67% lower time commitment. So that's a tremendous reduction in exercise and a lot less time spent doing it.

Similar results for skeletal muscles and cardiovascular improvement. So even though it was much less time commitment and fewer calories total burned, there was a strengthening of the muscles and overall cardiovascular health, similar improvements to muscular oxidative metabolism. So the muscles were able to burn glucose at a similar rate with both forms of exercise. Even the one that took much less effort.

So high intensity activity can be difficult on joints and tendons, particularly for individuals not used to high impact activity. So you need to work up to this slowly, maybe starting with slow walking as your activity followed by rest, building up to fast walking, followed by slow walking, finally starting with something like jogging, followed by walking. So you can combine, you can bring your rest up to a slight activity like walking, and you can bring your high level activity up from walking all the way to two to running.

So another protocol looked at one minute of lower intensity activity with a one minute of rest. 10 minutes of activity in a 20 minute period. If done every other day, it leads to similar cardiac and oxidative metabolism benefits as much higher levels of of exercise. These protocols activate enzymes that improve ADP, ATP cycling, which is associated with improved glucose uptake. So you're going to be lowering your or your overall blood glucose, which also has health benefits. These protocols activate. Sorry, I just said that in addition to improved energy due to more efficient glucose oxidation, there are also antioxidant and anti-inflammatory effects, presumably due to improved oxidative metabolism. So the total oxygen you utilized your your VMAX is generally considered how in shape you are.

So when you run as fast as you can, how much oxygen you're taking in, how hard breathing measures, how in-shape you are, how much you're able to actually use that oxygen and use that glucose to provide your body with energy. And so the more in-shape you are, the more you're able to do this.

What high intensity training does is it actually exceeds your VMAX for a short period of time and that this is what actually gives you many of these benefits, even though you're not doing quite the same amount of exercise.

Effects are largely confined to the peripheral muscles and the circulatory system. What doesn't happen is remodeling of the heart muscle. So when you're doing longer term exercise, you can actually start remodeling your overall heart muscle and, you know, changing the shape of your heart. So it can it can reach higher pumping rates and higher throughput. And this is not going to do this. This is not going to remodel your heart for you.

So there is a there's a limit to what the benefits are, but everything else is going to improve. And the reason your heart doesn't improve is simply because of this ability to exceed your own VMAX, so your heart is, is essentially your your overall limit for how much exercise you can you can do. And when you do endurance exercise, you can change your heart, which enables you to get to a higher level of overall exercise.

But for short periods of time you can exceed your heart's own ability and your heart is able to react elastically to this. And so you don't just die. You're able to keep exercising, even though if you've exceeded your own, your own abilities of of of how fast your heart can pump and how much blood can flow through it. And because it can exceed its own abilities, it feels it doesn't need to remodel itself. So even though you periodically are doing this interval training that exceeds your heart's own abilities, your heart isn't going to change in response to this unless you do it for a much longer period of time. And that's why you sometimes need to have endurance training enabled to to increase your overall abilities. But the interval training will give you skeletal muscles that will give you increased oxidative metabolism, and it will have a whole realm of a whole, whole suite of benefits that are provided by exercise in general. The only thing that won't happen is the remodeling of the heart.

So overall blood glucose and after meal, blood glucose is reduced. And so this is excellent. This is this is this is combined with increased insulin sensitivity. So not only are you reducing how much insulin is in your body, right? Insulin is what it's going to start laying down fat. Insulin has all sorts of negative effects. You're at the same time reducing your blood glucose so you don't need the insulin to be there. So this is this is a really double benefit that is going to reduce all the problems of metabolic syndrome where you have high, high glucose, high blood pressure, clogged arteries, high triglycerides, high cholesterol, all of these things are going to be improved through both intermittent fasting and through interval training. So in my opinion, these are things that are essentially magic bullets for the ills of today's society, meaning metabolic syndrome. I'm not talking about politics and political ills, I'm talking about literal physical ones. These are sort of the easiest ways to get at these problems caused by essentially too much diet or it's too much sugar in our diet.

Again, while it's more efficient, there is some danger of high impact on joints of people who are not in shape. There are lower intensity versions of interval training that can give you those same benefits without stressing your joints out as much. And then you could be able to transition to a higher intensity version in elite athletes at the other side of things. 12/32 bursts at above peak capacity, 175% of max were able to replace eight four minute sessions at 85% maximum capacity. So think of that 12/32 bursts. So that's a total of 6 minutes replaced eight four minute sessions at a lower intensity. So the results were similar and they were able to do much less work for this for similar results, giving them a 2% improvement over a six week period. And remember, this is 2% improving on essentially Olympic athletes. So that's that's actually a lot of improvement over a very short period of time, six weeks.

So even in Olympic athletes, interval training will will improve their overall ability. In elite cyclists. 7/32 sessions were equal to 320 minute sessions. Again, this almost seems too good to be true. It's replacing much shorter amounts of time to give you similar benefits in a review paper.

The best results were found by combining duration training with the high intensity interval training, as you might expect, because then you get the effects of both. And again, this was done for looking at people who are essentially elite athletes. So if you combine this with with endurance training, you'll get even more effect.

But if you're a sort of more normal person and you're trying to get the most effect from the least amount of time, interval training on its own will do it for you. Exceeding the maximum benefit, exceeding maximum for short periods appears to be what is providing the benefit. So it's pushing yourself for a very short period of time. 30 seconds to a minute and it's what gives you the benefits to the peripheral muscular metabolism and overall health in non athletes with significantly more time effort relates very nicely to how hunter gatherers would have tried to minimize their overall efforts and maximize their the benefit of whatever they were doing.

So short bursts of effort are able to give you the best improvement in muscular strength, skeletal strength and ability to burn sugar and use it for energy.

At the other extreme, you have things like ultramarathons or marathons, even persistence hunting. So the hunter gatherers would have run other animals to death, essentially. And this was evolved once we became obligate mediators as Homo Erectus, presumably they were able to do it. And the idea is that as a biped out in a very sunny African Serengeti, you would have been receiving much less solar radiation because you just simply the upright stance would mean less sun was beating down on you and you could be active in the middle of the day. a

The other adaptation we have is increased sweating. The chimpanzees don't sweat nearly as much as we do, and so we're able to be active right in the middle of the day when everything else is trying to hide in the shade. And we could have just run other animals to death. While we're not as fast as them, we are much more efficient. And we were able to use that efficiency as a hunting technique.

So we are definitely we evolved for long distance running for things like ultramarathons and very efficient activities, even more so than other other animals. There are there are races between humans and horses that extend for 40, 60 miles. And the humans often win these races simply because we have that endurance ability. So this is something that we're all too evolved to do. We're all too evolved to have you basically high intensity weight training so we can do heavy, heavy weights over a over period of time and you gain large muscles because of this. However, both of these things do tend to have negative side effects.

Sometimes people try and come up with ways to make them less negative. So one of the problems with jogging is it puts a lot of stress on the knees and often will lead to flat feet. If you have a lot of arch support as you get older, our arches in our in our feet are essentially suspension bridges using tendons like cables holding the arch of the suspension bridge in place. And as you get older, those tendons tend to weaken and the suspension bridge starts to collapse and we get flat feet. So jogging and, you know, simply our lives can often lead to bad knees and flat feet. And so this makes running very difficult. So one of the solutions people tried to do was to do barefoot, running, assuming our ancestors had run barefoot, that this would help support the arches and make the knees have a sort of a better shock absorber because you land on your toe instead of pounding directly on your heel. And both of these things are true. However, this just tends to put the problem off and then you have difficulties with your Achilles tendon and so you end up with less stress fractures, but you end up with a shorter Achilles tendon and it can cause a lot of pain in the in the calf muscles and the tendon. So there's no really easy solution. Certainly endurance training is is very useful and can be, you know, helpful for remodeling the heart. But in my opinion, the interval training has better results.

So successful barefoot running would require a long training period of transition, allowing the tendons and foot ligaments to build, build their strength and persistence. Hunting and long distance running in general require a long buildup. However, if you can do these things, they're going to essentially eliminate metabolic syndrome really, really quickly. If someone has metabolic syndrome in there and they're running miles and miles every day, it's going to go away right away.

The problem is, if you have metabolic syndrome, it probably means you're out of shape and overweight and you're going to have a really hard time running miles and miles in every day. So this might not be a form of exercise that is available to you. And so interval training really seems to be a better way to get into it.

Same thing with heavy weight lifting. While it's good for you, weight lifting tends to burn belly fat faster than the subcutaneous fat. It's again going to be difficult. You can pull muscles easily, weight lifting, you can weight lift so much that you're so sore the next day you can't even move. And it's very easy to get into that because you don't really feel the damage you're doing to yourself when you're when you're lifting heavy weights.

Same thing with endurance training as you as you push through, you can push through what they call the wall. That wall is actually when you've used up all of your your glycogen reserves. So you're now you've gone through the sugar reserves of your body and now your body's starting to burn fat. That's very good for you. Very hard to get there, people. That's why people describe it as a wall. So it's it can be painful to push through there.

And the next thing that happens is you get the runner's high and you reach this sort of euphoric state where you don't feel the pain anymore, but this means you don't feel the pain anymore. And so this can lead to other things where you're stressing your whole metabolic system out so much that you simply collapse. And so we really should recognize that marathons are named after someone who was running back from the battle of Marathon in ancient Greece and succeeded in giving the message that they had won. But then he died. So you really can exceed your total ability.

So I've written a short a short system of of exercise that I've included with the post for interval training, and I've done it pretty on the high end of what exercise should be. So if you if you look at it, you know, if you think about getting out of bed, is the lowest amount of exercise you can do. And running an ultramarathon is the highest amount of exercise you can do. This would be sort of about three quarters of the way there. So a couple of hours a week, maybe halfway there, a couple of hours a week of pretty intense exercise. And it's going to get you in shape pretty quickly. But I would start out with a with a lower intensity version of the same workout if I were you and then sort of work up to it.

So if the version I have says, you know, jumping jacks and jogging in place, you might start off with doing 30 seconds of fast walking instead of jogging in places as a as a lower intensity version of the same thing and then work up to it. But I think this is a pretty good system to really, really build both strength and ability to to exercise while also increasing your resistance to decreasing your resistance to insulin and increasing your uptake of glucose. So I think it would combine very well with intermittent fasting, for example.

All right, thank you very much. I will do more mind and spirit related talks next time. Thank you.

Dr. Josh Stout - Interval Training - Sample Seven Day Plan

This plan is meant to be an example of a rigorous interval training regime.

For many people, a less rigorous approach would give many benefits with much less effort.

Consider substituting less strenuous versions of each exercise, particularly in the beginning.

Week 1-2: Beginner/Intermediate Level

Day 1: Morning - Cardio Interval

Warm-up (5 minutes): Light jogging in place, arm circles, leg swings.
Interval Session (20 minutes):
- 1 minute of high-intensity exercise (e.g., sprinting, jumping jacks).
- 1 minute of low-intensity exercise (e.g., brisk walking).
- Repeat for 10 cycles.
Cool Down (5 minutes): Slow jogging or brisk walking, followed by stretching.

Day 1: Evening - Strength Training

Warm-up (5 minutes): Jumping jacks, dynamic stretching.
Strength Circuit (20-30 minutes):
- Bodyweight squats (3 sets of 15 reps).
- Push-ups (3 sets of 10 reps).
- Lunges (3 sets of 12 reps per leg).
- Plank (3 sets, hold for 30 seconds each).
Cool Down (5 minutes): Gentle stretching for major muscle groups.

Day 2: Rest or Active Recovery

Day 3: Morning - Cardio Interval

Warm-up (5 minutes): Jump rope, light jogging.
Interval Session (20 minutes):
- 1 minute of high-intensity exercise (e.g., mountain climbers).
- 1 minute of low-intensity exercise (e.g., walking).
- Repeat for 10 cycles.
Cool Down (5 minutes): Slow jogging or brisk walking, followed by stretching.

Day 3: Evening - Core Workout

Warm-up (5 minutes): Dynamic core exercises (e.g., leg raises, twists).
Core Circuit (20-30 minutes):
- Bicycle crunches (3 sets of 20 reps).
- Plank variations (side plank, plank with leg lifts).
- Russian twists (3 sets of 15 reps each side).
- Superman exercise (3 sets, hold for 30 seconds each).
Cool Down (5 minutes): Gentle stretching for the core muscles.

Day 4: Rest or Active Recovery

Day 5: Morning - Cardio Interval

Warm-up (5 minutes): Light jogging, dynamic stretches.
Interval Session (20 minutes):
- 1 minute of high-intensity exercise (e.g., burpees).
- 1 minute of low-intensity exercise (e.g., marching in place).
- Repeat for 10 cycles.
Cool Down (5 minutes): Slow jogging or brisk walking, followed by stretching.

Day 5: Evening - Full Body Strength Training

Warm-up (5 minutes): Jumping jacks, light cardio.
Full Body Circuit (20-30 minutes):
- Dumbbell squats (3 sets of 12 reps).
- Bent-over rows (3 sets of 10 reps).
- Push-ups (3 sets of 15 reps).
- Plank with shoulder taps (3 sets, 20 taps each side).
Cool Down (5 minutes): Gentle stretching for all major muscle groups.