Is Cardio Good, and Is HIIT Better? by Joan Kent, PhD
Is Cardio Good, and Is HIIT Better?
By Joan Kent, PhD
My post last week described specific physiological benefits of aerobic training. It also covered the fact that endurance-type cardio – not strength work or interval training – can make rodent brains bigger.
Okay, forget how much that last part sounds like the premise of a 1950 sci-fi film. Let’s look at other research.
A long-term study followed 1583 middle-aged men and women with no personal history of either dementia or heart disease over a period of two 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 is ideal. It prevents cognitive decline and decreases the risk for dementia. No specific type of exercise was explored in that study, however.
And that’s a perfect lead-in to the long-raging debate over Cardio and High-Intensity Interval Training (HIIT).
Fans Of HIIT 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 have included them when teaching, as well.
But something interesting occurs when staunch advocates of HIIT compare the relative benefits of HIIT with 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 covered in the previous post, you can maintain a high level of work for a pretty long time.
HIIT pushers 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. And elite marathoners do it 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 get, but even I have done a couple of cycling time-trials on Mt. Diablo. The first time 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.)
Can We Combine Cardio With HIIT?
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. There’s evolutionary evidence that this way of training is precisely what we were always meant to do.
In his book Born To Run, Christopher McDougall reveals the blend of morphology, paleontology, anthropology, physics, and math that led to understanding how humans became the greatest distance runners in the animal kingdom.
There’s no way this article could do justice to McDougall’s fascinating and detailed description of the emergence of homo sapiens over Neanderthals (they were parallel species), and the evolution of humans as supreme hunters hundreds of thousands of years before the creation of the tools we associate with hunting (spearheads, bows and arrows).
A few of the evolutionary factors include upright posture to allow deeper breathing and limit retention of sun heat; the ability to release body heat through sweat, rather than panting like other mammals until they must rest or die of hyperthermia; and the ability to accelerate once the pursued animal has been run to exhaustion.
Human “persistence hunting” was a combination of endurance running primarily, plus some short sprints. Humans evolved to run in conditions that no other animals can match, and it’s easier for us.
Good At Endurance & For a Long Time
Endurance athletes can typically continue into what would be considered old age in other sports. In many cases, such as distance running, they can still out-perform teenagers or 20-year-olds until their mid-60s.
The most notable thing my then-35-year-old coach, Jim Karanas, saw at his first double-marathon was the age of most of the runners, who were 45 to 55. He said that told him immediately that the ultra-run was more of a mental than a physical challenge.
When workouts are always high-intensity, over-training is likely, as is failure to recover fully, and a high incidence of injury.
It’s also likely that someone will burn out after constant high-intensity work, making it feel like drudgery, instead of something to look forward to each day. Why not work out in a way that you’d enjoy making part of your schedule long-term?
McDougall quotes researcher Dr. Dennis Bramble, who said, “If you don’t think you were born to run, you’re not only denying history. You’re denying who you are.”
But let’s not limit this to running. Endurance athletes of other types display similar results. Stories abound of master’s cyclists in their 50s and up outperforming younger cyclists.
In his 50s, my coach used to race against the cyclists in the 30-year-old category – because he found could perform better against them than against the experienced cyclists his own age! Those guys kicked his butt when he was first starting to race.
Jim was also one of the few (and the oldest that weekend) to ride the notorious Furnace Creek 508 fast enough to qualify for RAAM.
So the choice isn’t really between short, intense intervals and long, slow cardio with a magazine. The right kind of training is not either/or, but both.
The cardio, of course, should be hard enough to cause a training effect, not help you catch up on your reading.
That permits a perfect combination that’s effective, enjoyable, sustainable over the long haul, and entirely in sync with our evolutionary nature.
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