stacked deck

In a previous post that I co-wrote with Jim Karanas, we described specific physiological adaptations of aerobic — aka cardio or endurance — training.

As you may recall, they include increases in blood volume, tidal volume, and stroke volume. The capillary network increases, as well, as do the size and number of mitochondria. Other changes also occur, but these are the ones that move oxygen to the working muscle.

Recent research has shown that endurance/cardio exercise — not strength work or interval training — can make rodent brains bigger.

Okay, forget how much that last part sounds like the plot of a 1950 sci-fi film. Let”™s look at other research.

A long-term study followed 1,583 middle-aged men and women with no personal history of either dementia or heart disease over 2 decades. Before-and-after tests done 20 years apart showed that the ones who had kept in shape tended to have larger brains, while the poorly conditioned participants had lost gray matter.

Holding on to gray matter prevents cognitive decline and decreases the risk for dementia. No specific type of exercise was explored in that study, however.

And that leads us to the long-raging debate over Cardio and High-Intensity Interval Training (HIIT).

HIIT Advocates Always Stack the Deck

Let me be clear: I have absolutely nothing against high-intensity intervals. I use them often in my own workouts and when teaching.

But something interesting occurs when staunch advocates of HIIT compare the relative benefits of HIIT with those of standard cardio.

They tend to cheat.

In the hands of the die-hard HIIT fan, the word “cardio” has become code for lame-o exercise at the lowest levels of intensity. It should come as no surprise that the benefits — if any — of such lame workouts would fall far short of the benefits of HIIT.

And no one challenges the criteria. So let”™s challenge them.

You Can Go Hard AND Long

It”™s simply not true that intense training must involve short intervals of, say, 20 to 60 seconds. If you train well aerobically — and train seriously enough to achieve the aerobic benefits above — you can maintain a high level of work for a pretty long time.

HIIT advocates seem to ignore the fact that elite marathon runners, for example, run faster than 5-minute-mile pace for 26.2 miles. Most people would find it difficult, if not impossible, to run a single 5-minute mile. It”™s a fast pace. Elite marathoners go faster than that for a couple of hours.

As Matt Fitzgerald — well-known marathoner, trainer, and author of several books and many articles — states, “well-trained endurance athletes really don”™t have to slow down much as they increase the duration of their efforts. We are not the folks reading magazines on elliptical trainers.”

I”™m the furthest thing from an elite athlete you can find, but even I have done a couple of cycling time-trials on Mt. Diablo. The first one took me 44 minutes at a consistent heart rate of 173 — quite high for me, making the climb a combination of hard and long. (Okay, I told you I”™m no elite athlete.)

The training combination that appeals to me most is to fit a set of about 8 intense intervals into a long training of moderate or moderately high intensity.

It”™s not just my personal preference, though. Evolutionary evidence suggests that this way of training is precisely what we were always meant to do.

(Part 2 will explore the evolutionary reasons that this is what we”™re meant to do.)

Joan Kent

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