Short, intense workouts offer health benefits

Host Amber Smith: Upstate Medical University in Syracuse, New York invites you to be "The Informed Patient" with the podcast that features experts from Central New York's only academic medical center. I'm your host, Amber Smith. High-intensity interval training workouts have been popular in recent years, and not just because people like concentrated workouts, but because of the health benefits, which are still being understood.

My guest is exercise physiologist Carol Sames, and she'll explain. She's an associate professor of physical therapy and physician assistant studies at Upstate.

Welcome back to "The Informed Patient," Dr. Sames.

Carol Sames, PhD: Thanks so much, Amber.

Host Amber Smith: I want to start by asking you about a specific study in the Journal of the American Medical Association's journal JAMA Oncology. It said that people who moved fast for at least three minutes a day significantly lowered their risk of 13 types of cancer. How can that be?

Carol Sames, PhD: So essentially what these investigators did was they used data that came out of the UK Biobank study, and they prospectively looked at individuals. And these cancers are actually related to either low levels of physical activity, higher levels of obesity, or sedentary behavior. And what they found was that these very short, brief bouts of intense -- we would call it higher-intensity activity -- reduced their risk for these 13 cancers.

Host Amber Smith: So what counted as higher intensity? Or, what kind of activities are we talking about?

Carol Sames, PhD: So things like moving up the stairs really quickly, or fast walking, but again, for brief periods of time. About 92% of all of these bouts were a minute, and then 97 were up to two minutes. So just, those really brief types of moving quickly for just a very brief period of time.

Host Amber Smith: So did the movement have to happen all at once, or could there be like three one-minute bursts, versus one three-minute burst?

Carol Sames, PhD: There were multiple bursts because they actually used a minimum of 3.4 to 3.6 minutes. So in that case, you were looking at multiple bouts of these quicker activities. So maybe I'm in the basement, and I live on a two-story house, and I'm going up those basement steps and then walking quickly to the next set of steps and getting to the top of the steps. And that would probably take about a minute.

Host Amber Smith: Did the risk drop more if there were more fast movements?

Carol Sames, PhD: So they did say that. They actually said that if they were between 3.4 to 3.6 of these vigorous minutes, they had about a 17% to 18% reduction in the cancer risk compared to no vigorous minutes at all. And then they saw that 4.5 minutes was associated with a 31% to 32% reduction in those 13 physical activity-related cancer incidences.

Host Amber Smith: So which are the cancers that appear to have this protective effect, or which ones really aren't covered by this?

Carol Sames, PhD: So here's where it becomes interesting because you have a combination of lack of physical activity, and that's a risk. You also have increased percentage of body fat, or body composition. We sometimes call it obesity. And then you have sedentary lifestyle. And those three are intricately woven together. They're not separate.

So generally, think of it if I am not active, if I'm inactive, I probably engage in sedentary activity, and then there's a chance that maybe I have gained some weight. And usually when you're talking about gaining weight, it usually tends to be fat mass. So it's very difficult to tease out that these are only what we call the physical activity-related cancers or low physical activity. They're really all three intricately designed and interwoven.

But the cancers were bladder, breast, rectal, colon, head and neck, myeloma, myeloid leukemia, endometrial, esophageal, upper stomach, renal, lung, liver. But, we also know that there's some other cancers that are associated with obesity specifically and / or sedentary behavior. So, that's also important to understand.

Host Amber Smith: Do I understand correctly this study focused on people who don't exercise and how they compared with people who exercise regularly?

Carol Sames, PhD: All the individuals in this study, actually five and a half years before they started collecting the data, they had all filled out a questionnaire and said, we're not active, OK. So that's always, that's a limitation of the study. You don't know if people might have become more active in that five and a half years. But they wore what we call a wrist accelerometer, which is like having a Fitbit or an Apple Watch on, and it tracks movement and the speed of that movement, and so, they were looking at people who had these fast minutes compared to people who didn't have these fast minutes.

Host Amber Smith: Previously you and I have talked about the benefits if someone doesn't want to do sweaty workouts, of doing less strenuous activities like walking. But this study is different because it's all about the benefits of bursts of vigorous activity, right?

Carol Sames, PhD: Specifically with a reduction in these cancer risks, yes.

So, this study was about 96% Caucasian individuals. So this study would need to be replicated. This is looking at relationships or associations. This is not an experimental design where they looked at cause and effect. So that's always important to understand.

So when you get this type of results, you want to see this replicated with different populations, to just really see: Is this a stronger relationship? And then kind of go from there. So this is a first step, and I think it really does line up with some of the research that we've seen in sedentary behavior because what we have found with sedentary behavior is that if you just get up every hour for one to two minutes, compared to just sitting all day for eight hours, you actually reduce some of the metabolic risks. Insulin sensitivity improves, glucose levels come down, so you can kind of see how these two might be conjoined at some point, in terms of sedentary behavior.

You know, one of the big concerns now is sedentary behavior, sedentary lifestyle. So if I got up this morning and I rode my stationary bike for 30 minutes, and then I come to work and I sit for eight hours straight, that 30-minute stationary bike burned off calories and had some good cardiovascular benefits. However, if I sit for eight hours straight, there's some negative metabolic things going on that we need to address. So, sedentary lifestyle or sedentary behavior is considered a separate risk factor from physical inactivity, not achieving the guidelines.

There are two different ones. So that's something that people really need to understand because I think it's easy to say, I got my work in, I did my exercise, I'm achieving the guidelines, but now I'm sitting all day.

Host Amber Smith: Well, it is a little alarming because there's a lot of jobs that that's what you do. You're pretty much seated all day.

Carol Sames, PhD: That's probably a good reason to, if you're able to, just stand. And some of the research is, you know, we're not talking (about) having to stand and walk for 15 minutes every hour, but just for a couple of minutes seems to negate some of those poor metabolic outcomes. More research, again, more replication is needed, but the research is leading in that line that it is a separate risk factor, compared to not achieving the physical activity guidelines.

Host Amber Smith: Well, focusing back on cancer a little bit, do researchers have an understanding of what is happening in the body during these bursts of activity or during these short spurts of exercise that help protect us from developing cancer? Do they know why that's happening?

Carol Sames, PhD: There's some models and some theories, and so when we move quickly, we need muscle to move, and so that muscle has to contract and that muscle requires energy, or we're not going anywhere. And so what happens is that we have glucose that's stored in our muscle. And so when we move, we immediately have our energy there and we're able to move. They're thinking that that is what's occurring to keep insulin sensitivity at a normal level, versus a reduction of insulin sensitivity.

We also know if there's not a lot of movement, you start a chain of inflammation and inflammatory proteins. And if we are not moving for periods of time, we get like chronic inflammation. And that's a real hot topic now in the research world because chronic inflammation just leads to all kinds of bad things, oxidative stress, DNA damage -- actually our DNA, it becomes damaged. And we know that individuals who gain weight, that is linked to chronic low grade inflammation.

And so, adipose tissue actually produces pro-inflammatory substances. So at least being active kind of is a way of stopping some of that bad inflammation that can occur when we're not moving.

Host Amber Smith: This is Upstate's "The Informed Patient" podcast. I'm your host, Amber Smith, and I'm talking with exercise physiologist Carol Sames, about high-intensity interval training.

Let me ask you to please define high-intensity interval training and how it compares with something called vigorous intermittent lifestyle physical activity.

Carol Sames, PhD: So that vigorous intermittent activity that this study looked at is very short bursts. These are not longer bursts. They're intermittent, so they're occurring at multiple times during the day. So that is distinctly different from high-intensity interval training.

High-intensity interval training is activity that is at a higher intensity. That's similar between the two of them. But generally it is set up that you're trying to achieve at least a minimum of an 85% of a heart rate max intensity -- so it is higher intensity -- that you're doing it, an activity for say, 20 or 30 seconds, and then you're doing something that is lower intensity for a rest period. And then you're doing another bout of high intensity, and then something lower intensity. And generally the goal is to try to do about 20 to 30 minutes of that high-intensity interval training. Now, people don't necessarily start there, but that is the general idea.

The activities that can be included in high-intensity interval training can be anything. They can be strength training activities. They can be things like walking, or you could potentially, if you had a stationary bike, you could hop on your bike and go for 30 seconds and get off and do something that is lower intensity.

It could be functional things. As we get older, functional exercise is really important because it's the stuff that enables us to live independently. So, picking things off the ground, getting out of a chair, all of those kinds of activities, maybe even climbing the steps. So, higher intensity interval training is just a longer period of time. Usually 20 to 30 minutes is what we're aiming for. And, at a higher intensity heart rate, at least 85% of maximum heart rate.

And this vigorous, intermittent lifestyle, physical activity is really just trying to capture things that you might be doing in your every day that you do for very brief periods of time.

Host Amber Smith: So would a person who does a half hour long HIIT workout get the same reduction in cancer risk as someone who runs to catch their bus?

Carol Sames, PhD: Ultimately the person who's doing 20 to 30 minutes of a HIIT workout, there's so many other benefits involved than just me running to catch my bus. I'm assuming if I'm running to catch the bus, it's probably not taking more than 30 seconds. You know, something that's, maybe it's a minute, but it's very short.

There is value there. But if we're looking at like total benefits, that 20 to 30 minutes of HIIT is going to be strength training, potentially, depending on how you have set up. It could be core strength. It's cardiovascular in nature. And we know that cardio respiratory fitness has a strong impact on reduction of risk of cardiovascular disease. So the better my fitness level, the lower my risk is of developing cardiovascular disease. And you know, when we talk about cardiovascular disease specifically, coronary artery disease, that is the No. 1 killer of adult Americans. So, there are other benefits that are going to occur with that longer duration, higher intensity activity.

People think that high-intensity interval training is only for like athletic, high fit people. And it's not. You can set up a HIIT workout for somebody in a chair. Do you know what I mean? Like it doesn't, you don't have to have this high level of fitness to do a HIIT workout. So, if somebody is really low fitness, it doesn't take a whole lot of activity to get to 85% of their maximal heart rate, because just standing up out of a chair could be it, right?

I think what happens is we kind of associate this HIIT workout, this high-intensity interval training with individuals that are highly fit. And that's a problem because you kind of get bang for your buck with HIIT. It doesn't take a whole lot of time. You can do it in your home. You don't need stuff. Body weight, a chair, a wall. I don't need a lot of stuff. And there is tremendous value because you can add strength training things to this type of workout. And we certainly know older adults absolutely need to do strength training three times a week. And it should include power activities. So that's like getting out of a chair. That is going up your stairs.

Host Amber Smith: How do HIIT workouts compare with other things like swimming or pickleball -- pickleball's a popular sport right now -- or rollerblading?

Carol Sames, PhD: So pickleball really is short bursts. I mean, that is a perfect example of something that could actually be high-intensity interval training because you're playing so long for a point, you're moving around kind of very quickly.

Swimming and rollerblading could be set up as something that is higher intensity, or it could be something that's set up where you're just doing a continuous moderate intensity activity. So it just depends on how you set that up.

If I'm swimming, I could do intervals, right? Where I say I'm going to swim a half a lap fast, as fast as I can go, whatever that is. And the next half lap -- slow. And rollerblading, you could do the same thing. I'm going to roller blade quicker to the next light pole, and then I'm going to go easier. So those two activities could be set up to be a HIIT type of a workout, at least interval training workout, just depending on what your goals are.

But pickleball, that is bursts, that is, it's like soccer or basketball, those kinds of activities where there's a burst and then a little bit of a rest, a burst, and then a little bit of a rest.

Host Amber Smith: Is there a concern that people might overdo it with this, with the bursts like that?

Carol Sames, PhD: So certainly the selection of your activities and the intensity that you go for those activities could be too much for an individual, not just too much cardiovascularly, but even for the musculoskeletal system. So if we have somebody that maybe is of lower fitness, we might not want to have them doing a lot of hopping and jumping types of activities because they haven't been doing that activity, and that's tough on the musculoskeletal system.

So, how would I know that it was too much? Well, I'm not recovering. So if I'm attempting maybe two days later to do another one, and I'm just, I'm tired, I have a lot of muscle soreness. You know, when somebody has been inactive and they start to move, they're going to have some muscle soreness, OK? But it shouldn't be so much muscle soreness that I'm struggling to go downstairs or upstairs or walking. That's an indication that what I have done is a little too much for my current fitness level. So, everybody has it in them to do too much. This is not a short race. This is about health, and this is long. We're playing the longevity game here. So we want to be active every day.

We're not going to, in one day of high-intensity interval training, negate maybe all of the poor health choices I've made in the past. So I think that's important for people to understand. And you can start at any point in your life. So that's also important to understand.

Host Amber Smith: Aside from reducing cancer risk, let's talk about some of the other medical benefits that have been associated with interval workouts. Not to be confused with the benefits of exercise in general, but for instance, do HIIT workouts have an effect on our immune system?

Carol Sames, PhD: They would, just like general benefits. So, absolutely. And we want to make sure that we're not overdoing it because if you overdo workouts, you actually, you impair your immune response. So that's why it's really important to understand like, is this too much for me?

As I just mentioned, HIIT workouts improve cardio respiratory fitness at a greater level than just more moderate intensity activity. And we now are seeing research that suggests that that provides greater risk reduction for cardiovascular disease. So that is a benefit.

The other benefit is what, when you do higher intensity activity, you burn more calories per unit time, so, say, per minute. So they become efficient. That is a tremendous benefit for people who are time pressed. You know, all of us have 24 hours, but we fill it up differently. And so if I only have 20 minutes, I can get kind of bang for my buck.

The other advantage of a HIIT-type training, versus a continuous cardiovascular activity is, I can put those components that I need. Say I'm really weak in my hip flexors, I can add some hip flexor activities in there, or core, or I can add activities into my hip workout that I really need to work on.

If I want to work on quad strength, I might try going up and down the stairs a couple of times. So that's very beneficial. But the average person doesn't want to do a HIIT workout, probably, every day because that really could put them, possibly over training, where they're not recovering

Host Amber Smith: Well, Dr. Sames, I really appreciate you making time for this interview and telling us about HIIT training.

Carol Sames, PhD: Thank you so much, Amber.

Host Amber Smith: My guest has been exercise physiologist Carol Sames. She's an associate professor of physical therapy and physician assistant studies at Upstate.

"The Informed Patient" is a podcast covering health, science and medicine, brought to you by Upstate Medical University in Syracuse, New York, and produced by Jim Howe.

Find our archive of previous episodes at upstate.edu/informed.

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