By Jay Diamond
Sometimes I hate science. Science often tells me unintuitive things backed by evidence that I simply don’t want to know. Science is truth – and unfortunately sometimes the truth hurts.
But let’s take a step back.
I’m often asked a seeming silly, simple question which isn’t actually simple or silly at all. Unfortunately it’s often asked by fitness deniers – that is, people who don’t believe that physical activity will actually have an impact on their lives, or those who just don’t want to be active. Their question is intended to have me admit that it’s all really conjecture… all hyperbole.
Does physical activity actually improve health?
The answer is an unequivocal “yes”, but the surprising fact is how recently we’ve discovered this. When the amazing Jack LaLanne opened his first fitness club in Oakland in 1936, he had a vague notion, based on anecdotal evidence, that physical fitness had a positive impact on health. It turned out he was right, but it wouldn’t be proven by science for more than a decade.
In 1949, Dr. Jerry Morris decided to figure out why heart attack rates were on the rise in post-World-War II London. Sampling workers on double-decker buses, he quickly discovered that the drivers had a much higher rate of coronary incidents than the conductors. These men, of similar age, social standing, and in the same working environment, had one large discrepancy in their daily activity: the drivers were sedentary while the conductors didn’t stop moving, ascending and descending 500-750 steps per working day. There are certainly other factors at work, like the stress level of both occupations (driving can be quite stressful while the conductors were predominantly in social situations), but the overriding outcome that exercise is beneficial on cardiovascular health is irrefutable. Morris went on to confirm this by studying postmen vs. sedentary mail clerks.
I’m still stunned that we’ve really only known this connection for ~60 years…
This is about the time when the fitness deniers talk about Jim Fixx, the author who started a running craze in the 1970s and dropped dead of a heart attack while running in 1984. I remind them that there are lots of factors in health, that Fixx was a heavy smoker prior to his running conversion, he was genetically predisposed to coronary disease, and that you’ve gotta die sometime doing something (if many of your waking hours are spent running, well, you do the math…).
So exercise, in fact stressful exercise, is good for you (Morris also discovered that light activity wasn’t sufficient to stave off coronary disease).
Taking this to the next level is High Intensity Interval Training (HIIT), with variants operating under various names (Sprint Interval Training, Tabata, etc.), is the concept of going full out (“high intensity”) for a short period, followed by a short period of rest, and repeating. The duration, peak output, and number of repetitions vary, but the core concept (and results) is generally the same. And I hate it. Because it’s hard. But facts are facts, and there is some impressive science behind HIIT.
What if I told you that you could exercise under 10 minutes a WEEK and get the same results as 5 hours of exercise?
We all love a quick-fix, and HIIT sounds like exactly that. It sounds like a scam – but it’s not. Unfortunately you will hate every moment of that 10 minutes of exercise.
Scientists took two groups and put them through the following routine three times a week:
- Group 1 rides a stationary bicycle 90-120 minutes. The pace is sustainable throughout the period.
Total for the week: ~5 hours
- Group 2 rides 20-30 seconds at their maximum pace- outside of their comfort zone. Then they rest for 3-4 minutes. Rinse & repeat 4-6 times for a total of 2-3 minutes of exercise.
Total for the week: ~6-9 minutes
After two weeks, both groups showed identical increases in endurance and capacity, as measured by time trials and biopsies. This came after lots of tests making rats swim under similar endurance splits followed by dissection, and has been followed up with numerous studies on humans.
HIIT is the ultimate response to “I really want to get in shape but just don’t have time”
Despite quite a bit of compelling evidence I personally don’t do HIIT. A few reasons why:
- Fewer calories burned in HIIT – although that’s low on my list
- Greater chance of injury – although probably small
- I suck at it – but likely everyone feels that way.
- I enjoy a long cardio workout and I simply don’t enjoy HIIT. I quite enjoy the rhythm of doing an hour of cardio, sweating through my clothing and feeling strong at the end.
- I love to cheat and I’m really good at it. When I’ve tried intervals I end up simply doing a slightly increased pace for much, much less time – which is WORSE than the extended cardio session.
- The first goal of exercise is really not to die and HIIT makes me feel like I’m going to die, which, if you’ve read my first blog in this series, motivated me to start a path to fitness.
Finding a balance between your comfort level, time, and fitness goals is key to a sustainable health program. Science gives you the facts, and if you have the facts you can make informed decisions to put yourself somewhere on the scale from sedentary to torture.
Would you endure 10 minutes of pain in the name of science?
- Coronary Heart-Disease and Physical Activity of Work
- A history of physical activity, cardiovascular health and longevity: the scientific contributions of Jeremy N Morris, DSc, DPH, FRCP.
- Six sessions of sprint interval training increases muscle oxidative potential and cycle endurance capacity in humans
- Is high-intensity interval training a time-efficient exercise strategy to improve health and fitness?
Jay Diamond is the founder of Reason4Reason – a skeptical activist group based in the San Francisco bay area. He holds dual masters degrees in engineering and business and has managed both startup companies and hundred-million-dollar programs for Fortune 50 companies. Growing up in Canada, he performed magic, studied science, and became aware of the skeptical movement. Jay has lectured around the world on science & technology, business, and skepticism.