Tag: cardio

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My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

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This week’s Jockology column in the Globe and Mail takes a look at “micro-exercise”: what is the smallest bout of exercise that actually offers health benefits?

Exercise generally obeys the normal rules of mathematics. You can replace one 40-minute workout with two 20-minute bouts, or even four 10-minute bouts, and get roughly the same health benefits. But beyond that, the rules break down: Exercise in bouts lasting less than 10 minutes simply doesn’t count.

At least, that’s what exercise physiologists and public-health authorities have been telling us for years.

But influential groups such as the American College of Sports Medicine are now reconsidering the value of ultra-short bouts of activity, and a new Canadian study suggests that the gradual accumulation of “incidental physical activity” – sweeping the floor, taking the stairs – in bouts as short as one minute can also contribute to your cardiovascular fitness level… [READ THE WHOLE ARTICLE]

The column focuses on the findings of a recent study by Ashlee McGuire and Bob Ross at Queen’s University. For more details on that study, check out Ashlee’s guest post describing the study’s results over at Obesity Panacea. Also, the print version of the study was accompanies by Trish McAlaster’s graphic, which hasn’t yet been posted online [UPDATE: now it’s posted here]. Unfortunately, it doesn’t really fit in this blog’s format, but nonetheless:

I’m reasonably confident that this is the first mention of the caloric expenditures involved in butchering small animals to make it into the Globe!

THANK YOU FOR VISITING SWEATSCIENCE.COM!

My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

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The age-old debate: which is “better,” interval training or continuous exercise? It’s a stupid debate — but I’ll get to that in a sec. First, a new study in the August issue of the Journal of Strength & Conditioning Research, from researchers in Spain. They put 22 physically active non-runners through one of three different eight-week training programs:

1. Intervals: Three workouts a week. Mondays were 4-7 x 2:00, Wednesdays were 3-5 x 3:00, Fridays were 2-5 x 4:00, with rest equal to the length of the interval.
2. Continuous: Three workouts a week, starting with 16:00 at 75% of vVO2max and building up to a high of 40:00 at 75% of vVO2max.
3. Control: Nuthin’.

Here’s how the three groups progressed (MAS is their speed at VO2max):

As you can see (and as the paper concludes), the interval training and the continuous training produced virtually identical results. Which proves… well… nothing, really. Comparing a steady diet of 100% intervals to a steady diet of 100% continuous runs is like one of those “If you could only bring one album to a desert island to listen to for the rest of your life, what would it be?” conversations. Every different workout provides a slightly different stimulus to the body, so trying to identify “the best” is a pointless exercise. For optimal performance and health, we need a mix of different workouts.

The authors of the new study make an important point when trying to explain why previous comparisons of interval and continuous training have produced mixed results:

[I]t may be suggested that the exercising intensity and the subjects’ training background influence subsequent endurance training adaptations.

This is key! Take someone who has been “jogging” five days a week for a few years and have them start doing hard interval sessions a couple of times a week, and you’ll see dramatic improvements. But if you have someone who has been doing sprint training but no sustained running for a few years, and then add a tempo run and a long run each week, you might see equally dramatic improvements. In neither case does this “prove” that one type of workout is best — it’s context-dependent.

So what’s the perfect mix of workout types? Science doesn’t have an answer, but elite athletes have settled into some consistent patterns through trial and error. A reader (thanks, Marc!) recently sent me a link to an interesting review published a couple of years ago in Sportscience (full text freely available) that analyzes this question very thoroughly based on studies of elite endurance athletes in many different sports. They conclude that there’s an “80:20” rule for intensity:

About 80 % of training sessions are performed completely or predominantly at intensities under the first ventilatory turn point, or a blood-lactate concentration. The remaining ~20 % of sessions are distributed between training at or near the traditional lactate threshold (Zone 2), and training at intensities in the 90-100 %VO2max range, generally as interval training (Zone 3). An elite athlete training 10-12 times per week is therefore likely to dedicate 1-3 sessions weekly to training at intensities at or above the maximum lactate steady state.

Other researchers like Carl Foster break it down into three zones rather than two, and say that athletes do about 70% of their training below threshold, about 20% at or near threshold, and 10% above threshold. That’s a pretty small diet of intervals. Of course, elite athletes have different goals (and more time to train) than the recreationally active volunteers in the Spanish study — so the breakdown of three workouts a week might be quite different from 10-12 workouts a week. Still, my advice for anyone at any level is to include at least one interval session and at least one continuous session in your weekly routine — even if you’re just training twice a week!

THANK YOU FOR VISITING SWEATSCIENCE.COM!

My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

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This week’s Jockology column in the Globe and Mail takes a look at the debate about whether too much exercise is actually bad rather than good for you, drawing on recent studies about cardiac fibrosis in elite endurance athletes, epidemiological data from the National Runners’ Health Study, and — to be topical — Tour de France riders:

Given the number of cyclists in this year’s Tour de France who have skidded off mountain passes, been sideswiped by passing cars or catapulted into barbed-wire fences, it’s obvious that riding in the Tour can be hazardous to your health.

But what about the riders who make it to the finish line in Paris, having covered 3,430.5 heart-pounding, leg-draining kilometres in three weeks? Does their gruelling training regimen make them healthier, or does too much of a good thing leave them worse off? Medical opinion has flip-flopped over the years as our understanding of the heart’s response to exercise has increased, but a new study on the most important outcome of all – staying alive – suggests that Tour riders do better than average. [READ THE ARTICLE…]

 

THANK YOU FOR VISITING SWEATSCIENCE.COM!

My new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Also check out my new book, THE EXPLORER'S GENE: Why We Seek Big Challenges, New Flavors, and the Blank Spots on the Map, published in March 2025.

- Alex Hutchinson (@sweatscience)

***

It’s widely known that the old “220 minus your age” equation isn’t very good at determining your maximum heart rate. So what’s better? A new study from the University of Hawaii, recently published online at the Journal of Strength and Conditioning Research, tested nine different prediction equations, along with a surprisingly accurate way of determining your true max heart rate in about 30 seconds (sort of).

The study looked at 96 volunteers with an average age of about 22. That’s the first caveat: these results are only relevant for people in that general age group. And the volunteers were phys ed students, which means they’re likely to be more physically active than the general population.

I’ll start with the less interesting part of the study. Here’s the data from the equations they tested for all 96 subjects:

“CHRmax” is basically the “real” max heart rate. So they conclude that Gellish2 (191.5 – 0.007*age^2) and Fairbarn (201 – 0.63*age for women, 208 – 0.80*age for men) are the most accurate for this population. Maybe so — although trying to fit a function of age to data taken from subjects who are all virtually the same age seems a little weak to me. But the bigger problem is something they themselves note in their introduction:

The most commonly used Fox equation [i.e. 220 minus age] has been reported to have an SD [standard deviation] between 10 and 12 b/min. Thus, when estimating HRmax using the Fox equation, approximately 66% of the population should fall within +/-10 beats of the actual HRmax, but for the remaining population, the actual HRmax could differ by as much as 12–20 b/min or more.

I don’t know why they’re saying this is a property of the Fox equation. This is a fundamental property of human physiology: heart rate varies between individuals, so ANY equation based only on age will be more than 10 beats off for at least a third of the population. So for practical exercise prescription purposes, who cares which equation is more accurate?

Much more interesting is the way they calculate HRmax. They did the usual graded treadmill test to exhaustion to determine “true” max for 25 of their volunteers. Then they tested two other protocols. One was the Wingate test, which is basically 30 seconds all-out on an exercise bike. It was a crappy predictor, more than 10 beats below the actual average.

The second test was really simple: they had the subjects sprint as hard as they could for 200 metres on a standard track, with a running start. That’s it. And they measured their heart rate during the sprint. The average from the treadmill test was 190.0; the average determined from the 200m sprint (which takes a little over 30 seconds for most people) was 190.1. Pretty darn good.

Now, there are some caveats. The fact that the averages were close doesn’t mean everyone got identical values on the two tests. In fact, the “mean absolute error” was 5.8 bpm — but since the treadmill test was higher about half the time and the sprint was higher the other half, the averages balanced out.

Also, they didn’t do just one 200 sprint. They actually did two, but separated by at least three days. Each individual sprint, on average, underestimated the HRmax. The first sprint produced an average of 187.9; the second sprint produced an average of 186.3. So this test wasn’t as reliable at getting right up to HRmax. But when they gave people two tries, most people seem to have nailed at least one of the tries. Presumably if you gave them five tries (spread over several weeks), you’d get an even higher average max value. Of course, the same is true of the treadmill test: not everyone will execute it perfectly, so if you do it twice, the average value will probably creep up a bit. But what this study tells us is that, for this group of subjects (and remember, these are young phys ed students who are capable of sprinting 200 metres all out without pulling up lame halfway), give them two cracks at sprinting 200 metres and then take the highest heart rate they produce, and you’ll have a very good estimate of maxHR. It’s a heck of a lot cheaper and quicker than a graded exercise test — and a billion times more useful than any equation based only on your age.