00:01
Hey everyone, it's Mikki here. You're listening to Mini Mikkipeida on a Monday. And today I want to chat about the health benefits of vigorous over moderate activity and what new wearable data tells us. So this is based on a paper that was published in 2025 that looked at the UK Biobank.

00:27
data set and I'll go into the details here but this is over 73,000 individuals and it was published in Nature Communications last year and there was an excellent journal club podcast put out by Rhonda Patrick and Brady Homer on found my fitness podcast. It was over two hours long. It could have been close to three hours actually. So I wanted to bring this into the micipedia ecosystem.

00:54
and distill it down to some super interesting and important information that I think that you will really like in this format of around 20 minutes or less. So for decades, the WHO physical activity guidelines and every national guidelines, including ours in New Zealand, have been built on this neat little rule, if you like. One minute of vigorous activity is worth two minutes of moderate activity.

01:22
That's why the guidelines say that you either need 150 to 300 minutes of moderate activity a week or 75 to 150 minutes of vigorous activity. The sort of tidy one to two ratio. For what it's worth, honestly, I think most people need more than that 150 moderate, but anyway. This new paper published last year in Nature Communications from Emmanuel Stamataki's group at the University of Sydney, the same group behind the

01:51
Vilpa Research, which I talked to Martin Gabbala about, super fascinating, vigorous intermittent lifestyle physical activity. They've tested the assumption properly for the first time, does that one to two ratio exist, using wearable data from over 73,000 people in the UK Biobank data set. What they found is that one minute of vigorous activity is not worth two minutes of moderate. It's worth anywhere from four to nearly 10 minutes of moderate.

02:20
activity depending on which health outcome you care about. So the one to two rule that we've been using for decades is a substantial departure from what the data actually shows. Now, before anyone sort of panics doesn't mean moderate activity is useless at all. And it doesn't mean that you need to go and do the Tabata intervals as the only way to train. But what this does mean is we've been systematically underestimating how powerful

02:48
vigorous activity really is. And importantly, when I tell you what the researchers actually classify as vigorous, I think you're going to be surprised because it's probably not what you're picturing and it certainly wasn't what I was thinking. And we'll get there. So today I want to chat to you about the study, talk about what vigorous really means, unpack the findings and the mechanisms, and then land on what this practically means for you. And I think this is especially important for

03:16
for those people who may not be doing much activity at all. Although I think those of you who are like me who are pretty active and I know there's lots of people like that in my audience, I think you'll find it really interesting regardless and useful. So a quick background about where this one to two rule came from. once you understand that, you're probably going to figure out that it was never really a great rule to begin with. So it is based on METS, metabolic equivalence of task.

03:45
One met is what you burn just sitting still. Light activity is roughly one to three metts. Moderate activity is three to six metts. And vigorous is anything above six. The logic being vigorous activity burns roughly twice as many calories per minute as moderate. So you need half as much of that to get the same benefit. The problem is that this assumes health benefits equal calorie burn. We know that's not true, right?

04:10
and it was never actually tested against long-term outcomes like heart disease, cancer, or diabetes. On top of that, the studies informing the guidelines used self-reported questionnaires. And we are humans who are just inherently flawed, right? These were people trying to remember how many minutes they've done last week. Self-report is noisy. People forget the incidental stuff. Questionnaires only count bounce of 10 minutes or longer. So running up the stairs,

04:39
sprinting to catch the bus, playing football with your kids, chasing the dog. None of that gets captured. Every minute of incidental short burst vigorous activity essentially disappears. And that's the gap that this new paper set out to fill. So Biswas and colleagues took 73,485 UK Biobank participants who wore a research grade wrist accelerometer.

05:05
24 hours a day for a week between 2013 and 2015. The mean age of these participants were 61.6 years. you know, middle age to older, slightly older than middle age really. And they were followed for an average of eight years for six outcomes. All-cause mortality, cardiovascular mortality, major adverse cardiovascular events, such as a heart attack or stroke or heart failure, type 2 diabetes,

05:34
physical activity related cancer incidence and cancer mortality. The methodological leap is how activity was measured. So the accelerometer measured movement directly in 10 second windows continuously. Fun fact, I used accelerometers in my master's research looking at childhood obesity actually. So I know exactly what they're talking about.

05:56
but you might not be as familiar with them. It's not your GPS watch. The raw data was then fed through a validated machine learning classifier that sorts each window into light, moderate, or vigorous based on the acceleration signal. So rather than asking people to estimate their vigorous minutes, the device measured it in real time, capturing every burst of effort, whether the person remembered or not.

06:21
They took real care to reduce this reverse causation. The idea that sick people are less active because they're sick, not the other way around. They excluded anyone with a relevant diagnosis at baseline and anyone who had an event in the first 12 months. They adjusted for the usual suspects, age, sex, ethnicity, smoking, alcohol, diet, sleep, screen time, medications, and family history.

06:49
My caveat with all of this is, this is observational data, so it's epidemiological research, so it doesn't show cause and effect. So I'll just slot that in here. Now this is a really clever bit. Rather than just saying more vigorous is better, they calculated what they called a health equivalence ratio. They asked, for a given percentage of risk reduction, say 10 % lower mortality,

07:15
How many minutes of moderate activity do you need to match one minute of vigorous? The same question was asked for light versus vigorous. So they're working out the actual exchange rate between intensities outcome by outcome. And as I understand it, this hadn't been calculated at this scale before in a study so large. Now, this is the bit that I find super interesting before I get into the numbers.

07:43
What does vigorous actually mean? And if you're a regular listener, when I say vigorous, you're probably picturing some sort of Norwegian four by four or one of Martin Gabola's 40 seconds, extremely hard, 20 seconds easy, that kind of thing. Where your effort is at 95 % of max heart rate, the kind of session where you're heaving at the end, reading every second. That's what vigorous means in the hit literature or the high intensity intermittent.

08:12
training literature. But that's not what vigorous means in this paper, which is what I was super interested in. Vigorous here is defined by met level, anything above six met's. And of course it does include hit, but it also includes a seedy jog, which is one of my favorite things to do. A fast walk up a decent hill. Don't mind that either. Cycling at a pace where you're breathing harder than normal, but could still say a short sentence. A lot of what we might call zone two work actually.

08:42
Carrying shopping bags up a couple of flights of stairs, purposefully chasing the kids or dog around the yard, this will be included as vigorous activity. And remember, this was measured by a wrist accelerometer. Intensity is judged by how much your wrist is moving and how much force is in that movement. So even lifting moderately heavy weights, where you're not covering distance, but your arm is moving against load, would be picked up as vigorous. So resistance training does get counted as well.

09:11
When I tell you that one minute of vigorous is worth eight minutes of moderate activity for cardiovascular mortality, I don't want you to hear that you have to do eight times more Norwegian four by fours. That's not what this is saying. One minute where you actually moving with intent and getting your heart rate up like a jog, a fast walk uphill, stairs with shopping, a genuine burst of effort is worth several minutes of pottering at a moderate pace. And that's liberating, I think, rather than intimidating.

09:41
So it opens up a lot more ways to accumulate these vigorous minutes across your day. And it doesn't have to be structured exercise. It doesn't have to hurt. It just has to be purposeful and reasonably hard. Okay, so to the numbers that were found in the paper. So for each outcome, the researchers calculated the equivalence ratio for a standardized five to 35 % risk reduction, one by one. For all course mortality that's dying by any cause,

10:10
one minute of vigorous equals about 4.1 minutes of moderate. So it's already double what the guidelines assume. For cardiovascular mortality, one minute of vigorous equates to 7.8 minutes of moderate. That's a huge departure from that one to two rule. For major adverse cardiovascular events, like a heart attack, stroke, heart failure, the ratio is one to 5.4. For type two diabetes, the biggest ratio,

10:39
This was 1 to 9.4. So nearly 10 minutes of moderate activity is equal to one minute of that vigorous activity, which is pretty extraordinary. Remember vigorous is a zone two type effort in this paper. For cancer mortality, the ratio is 1 to 3.5, which is still more than that one to two assumption, but it is a weaker signal. It's in fact the weakest.

11:05
which makes sense given that cancer has such a large genetic and environmental component. So what about light activity then? This is where numbers really get quite big. So to match one minute of vigorous for all-cause mortality, you need about 53 minutes of light activity. That's pottering, 53 minutes of pottering. For cardiovascular mortality, you need to potter for 72 minutes. For major cardiovascular events, you need to potter for 86 minutes. For type 2 diabetes,

11:34
You need to be pottering around for over an hour and a half. And for cancer mortality, that increases to 156 minutes. So nearly two and a half minutes of pottering around in your house or in your garden will match a single minute of that vigorous activity for the same outcome. However, here's the crucial nuance.

11:57
Light activity also does hit a ceiling. Beyond about a 15 % risk reduction for cardiovascular outcomes and diabetes, and about 10 % for cancer, more light activity did not give more benefit. The dose response curve just flattened. So you could potter around for hours and still be kept at around 10 to 15 % risk reduction. So the authors put it quite plainly actually, that not even the largest amounts of daily light activity can match the effects of moderate or vigorous intensity.

12:26
So the headline to this is that that 1 to 2 ratio should be dead in the water. It is somewhere between 1 to 4 and 1 to 10 depending on the outcome. Vigorous is 2 to 4 times more potent than we thought and light activity, or better than nothing, does have a ceiling. So, you know, let's just think for a moment about why vigorous is so disproportionately powerful. There are a few mechanisms and I'm just going to briefly cover here.

12:55
So the key principle is, the stronger the stimulus, the greater the adaptation. Your body only remodels itself in response to a signal loud enough to demand it. Higher intensity sends a much louder signal. And for cardiovascular health, when you exercise harder, blood flow speeds up, which generates sheer stress on the inside of your arteries. That sheer stress sounds bad, but it's the good kind. It signals endothelial cells to release nitric oxide and

13:24
prostaglycin, and over time your arteries become more flexible, more responsive, more resistant to atherosclerosis, which is plaque buildup on the arteries. And sheer stress doesn't really accumulate. It's about intensity, not duration. A light breeze for an hour doesn't do what a strong wind does. That's why in volume matched trials, vigorous still beats moderate for endothelial function. It's a big part of that one to eight ratio for cardiovascular mortality. For diabetes that

13:54
which has that remarkable 1 to 10 ratio, intensity matters because of what happens in muscle. When you work hard enough that your muscles can't produce all their energy aerobically, they generate lactate. So lactate isn't a waste product. It's a signaling molecule. It drives that glute 4 transporter that we have in the cells to the muscle cell surface, and this pulls glucose out of the bloodstream. And those transporters stay active for many hours after you stop. Lactate

14:23
also signals PGC1 alpha, which drives mitochondrial biogenesis, or the generation of mitochondria. We get better insulin sensitivity, better glucose control, better fat oxidation, and you need enough intensity to produce lactate, steady low intensity work doesn't do it. For cancer, the sheer stress story reappears. Circulating tumor cells, which are cancer cells that have broken off a tumor and are traveling in the bloodstream, have

14:53
mechanosensors and high shear stress can trigger their self-destruction. So vigorous exercise may literally be helping clear out these road cancer cells. There's also the inflammation piece. Higher intensity drives a bigger interleukin 6 spike during exercise and a larger anti-inflammatory rebound afterwards. And the last piece, is especially for listeners like me who are well over 40, type 2 muscle fibers. These are your fast twitch power fibers.

15:20
The first ones to go with age and the ones that only get recruited at higher intensities. So if you're only doing light activity, those fibers are sitting there atrophying and type two fibers matter for glucose disposal, balance, catching yourself when you stumble, for everything that determines whether you stay independent in your seventies and eighties. A full broken hip, spending weeks in bed, that pathway is the most

15:47
common route to mortality in older adults. Maintaining these type 2 fibers is genuinely longevity medicine and the only way to do this is to work hard enough to recruit them. What I will add though is that while zone 2 is considered vigorous in this paper, for something like fast twitch fibers, you do need to be engaging them within that zone 4 work, the super high intensity work. So I did just want to clarify that as well. Hit.

16:16
is obviously part of this vigorous category, but in the paper for a lot of the benefits, it incorporated that zone two work. So what was super interesting, and this comes up in Martin Gabala's work, is that this paper does sort of help explain why the VLPC studies, which was the same research group, showed such outsized effects from such small amounts of activity. So previous work has found that just three to four minutes of a day of that

16:43
Vigorous intensity lifestyle physical activity, which were little bursts of vigorous movement in normal life, was associated with a 45 % lower risk of major cardiovascular events in women and about a 40 % reduction in all cause in cancer mortality. When those numbers first came out, it seemed almost unbelievable really that you could have that risk reduction in just a few minutes a day. But with this equivalence data,

17:10
does make some sense. If one minute of vigorous is worth eight minutes of moderate activity for cardiovascular mortality, then four minutes a day of VLPA is equivalent to over half an hour of moderate activity. This is squarely in line with the guidelines. The numbers do actually hold together. So these are like two stories that have that same conclusion. So what do we do with this? First of all, stop thinking of a minute as a minute. A minute of purposeful heart raising

17:38
if it is worth four to 10 minutes of pottering. Those four minutes where you walked fast up the hill to the shops aren't just four minutes. For cardiovascular health, they're closer to 30 minutes of banked moderate activity. I think that reframe, not only it's accurate according to this picture, but it can be really motivating for people who just don't have their exercise dialed in. And second, the threshold for vigorous is lower than you think. You don't need to do HIIT every day. You need to get your heart rate level up to feel it.

18:07
breathing harder than normal, able to speak a short sentence, but not a long one, a jog, a brisk walk uphill, hauling groceries up the stairs, chasing your dog, pushing the pace on the bike, a set of step-ups at home, think purposeful effort rather than hard exercise. For all of this other than the type two fiber types, they really actually require that higher intensity activity. And then that comes to my third point.

18:34
that there is still real value in one or two properly hard sessions a week. The dose response in this study was linear for vigorous activity up to around 30 to 40 minutes a day. And at the higher end, we're talking 50 % or greater reductions in mortality and chronic disease. So while a few minutes of VILPA gives meaningful benefit, best results are still at the higher end. If you can tolerate a Norwegian four by four once a week, or twice a week, or genuine intervals,

19:00
That's when you really move your VO2 max, which is still one of the strongest predictors of longevity that we might have. And then fourth, don't discount that light activity, know, that non-exercise activity that I just love, but be realistic. Walking is great. Not being sedentary is genuinely protective, but you can't just rely on just building your steps. So you get 20,000 steps of very light activity in a day.

19:24
because you are capped at about that 10 to 15 % risk reduction for most things and zero for cardiovascular mortality. Inserting a few 60 second bursts of faster walking into your daily walk, interval walking if you like, converts some of that light time into moderate and even vigorous. And the return on that small effort is huge. And finally, a word on wearables. Most of the algorithms and devices like Garmin, Whoop, Apple Watch, Aura, Fitbit,

19:53
They still use the old 1 to 2 ratio to calculate heart points and activity scores. This paper is pretty strong signal that those algorithms need updating. For now, take the scores with a grain of salt. I mean, I say that, but I'm very much attached to my Garmin, to be fair. So when you're looking at set counts, remember that context matters more than the number. 10,000 gentle steps is not the same as 8,000 with a couple of brisk uphill sections in them.

20:21
and distributed across the day because we do want to avoid prolonged periods of sitting. some limitations, I've already mentioned one about it being epidemiology and to further that, it's observational, right? So these are associations, not proof of causation. The authors did a good job of reducing reverse causation, but residual confounding can't be completely excluded. And interestingly,

20:46
The UK Biobank also has a well-known selection bias, so only about 5.5 % of invitees responded. So it's a huge database, but there are a lot of people not participating. Participants who do contribute are healthier and more motivated than the general population. The authors note that this doesn't seem to materially distort mortality associations for what it's worth. Activity was measured for just one week at baseline with eight-year outcomes. A simplification.

21:15
though the strength of the signals from just one week's activity is fairly stable for most people over time. But again, take that with a grain of salt as you should for all epidemiological research. What epidemiological research does is it sets the scene for more research. That's how I like to look at it. The cohort was 40 to 79, probably just like us or near us.

21:40
So we can't extrapolate that exact numbers to younger adults, but the mechanisms apply across a lifespan. So it's worth mentioning that too. And none of these, think, undo the main finding, but I do think that they're worth holding in mind as you're reading through the paper, which is linked in the show notes, or listening here. So to sum all this up, Biswas and colleagues in Nature Communication 2025 is the first large device-measured study to directly test whether the one-to-two rule actually holds up.

22:09
which is what our physical activity guidelines is founded upon. It doesn't. The real exchange rate is closer to one to four for all-cause mortality, one to eight for cardiovascular mortality, one to 10 for type 2 diabetes, and vigorous activity is dramatically more time efficient than we've been giving it credit for. The other big message is that for most outcomes, other than those type 2 fiber types, vigorous isn't as extreme as the HIIT-adjacent framing that we often use. It's defined by that

22:37
metabolic equivalent task level. And it starts around a jog or a fast uphill walk. And it's genuinely accessible to almost everyone. And do remember that light activity, pottering is absolutely worth doing, but it does have a ceiling. So moving more does matter, but moving with intent matters much more. So I'm curious actually, this will be something you were thinking about for the week coming ahead. Start notice the little windows of vigorous effort that you already have.

23:06
or could easily create in your day. The stairs that you usually take slowly, or like me, the uphill section of my walk around the block, which I always do super slow. The walk to pick up the kids where you could push the pace for a minute or two. The moment when you're learning your car where you could be deliberately moving faster. Start treating those as high value health minutes that they actually could be. And if you train properly, keep going, but know that the stuff in between your sessions

23:34
is doing more than you thought. As always, hopefully you enjoyed this. um I loved listening to the podcast with Rhonda and Brady. It did get into the weeds. That's why I wanted to sort of bring it down to some of these highlights, um but I'll pop that in the show notes as well. Let me know your thoughts. I'm over on Instagram, X and threads @mikkiwilliden, Facebook @mikkiwillidennutrition, or head to my website, mikkiwilliden.com. Scroll right down to the bottom, pop your name in the little box and jump on my email list. All right guys.

24:04
You have the best week. See you later.