Walking Is Not Exercise: Why You Need Both Movement And Exercise
Movement is great. Move any way that feels good to you and this is certainly better than time spent sitting. And fitting in 10,000 or even 20,000 steps most days is fantastic. There are so many benefits to including movement throughout your day and reasons to prioritize movement goals like this. But for almost everyone reading this, I would not consider this exercise.
Exercise, in my thinking, is intentional movement that improves fitness, whether increasing muscle strength or improving cardiorespiratory capacity. Exercise is movement that places stress on our systems, so that cells respond and repair in ways that make us stronger. Hormesis, or a hormetic stress, is a strain on a system, temporary, and not so strong that it breaks the system, but a strain that allows the system to adapt and improve resilience. Exercise is a hormetic stress and it requires that we push, even if just a little, beyond what feels easy and comfortable.
So if you can tell me that you walk at least 8,000 steps most days and take the stairs rather than the elevator, I love these things! These clearly benefit your metabolic health, but they may not do as much for health span as more intentional exercise. And because being sedentary for prolonged times can undo the benefits of a great workout (i.e., if you have a solid 60 minute workout in the gym, and then sit for the next ten hours, minus a short walk or two to the break room, you’ve largely negated the benefits from that workout), both regular movement throughout the day and more focused exercise are of equal importance.
I want to use this article to explain how I think about both movement and exercise and suggest some ideas to help you start thinking about your goals for each of these.
MOVEMENT:
Being sedentary is an independent risk factor for cancer and cardiovascular disease. Moving throughout the day, even for very brief bursts, can significantly benefit your health. One study found that doing just ten body weight squats every 45 minutes during an 8.5 hour period of sitting had even more benefit than a single 30 minute walk for improving blood glucose balance. And most of us can find a way to fit in ten squats, or something equivalent (you can mix it up with pull ups or push ups or walking lunges) about once per hour - this is pretty simple, but also something about which we have to be thoughtful to achieve.
Quite a bit of research has also been done on exercise snacks in mitigating the health risks of being sedentary. Exercise snacks is a broad term that refers to brief, intense bursts of exercise. This would be something that gets you quite out of breath (if you’re monitoring your heart rate it would be at least 75% of your maximal rate) and lasts just one to two minutes in duration, and done at least every two to three hours of sitting.
Examples of exercise snacks could be one to two minutes of burpees, sprinting up stairs, jumping jacks or jumping rope, brisk walking lunges or using a Peloton (or any other cardio machine you may have) for a quick all out effort. Exercise snacks offer improvements in blood sugar balance, cardiovascular health, endurance and strength. But these benefits do require consistency with this practice, preferably including them every day.
Similar research has also looked at vigorous intermittent lifestyle physical activity (VILPA), which is essentially the non-exercise equivalent of an exercise snack. This might include one to two minutes done three times daily of something like walking up stairs (not taking the elevator), walking at a brisk pace (rather than a casual pace), or gardening activities such as moving a heavy wheel barrow. This research, done in people who identified themselves as non-exercisers, demonstrated a 40% reduction in all-cause and cancer mortality and about a 50% reduction in cardiovascular disease mortality risk.
EXERCISE:
So just moving throughout the day, with effort made to avoid prolonged stretches of sitting, and including one to two minutes of more vigorous activity a few times each day, will benefit your health. But for most of us thinking about how we can best optimize to improve our potential health span, we also need to think about exercise. Movement is great, but exercise is even better!
When I structure my weekly exercise goals the two main areas I concentrate on are high intensity efforts and strength training. This article focuses on vigorous exercise, and I will separately address strength training, since there is a lot to cover on each of these topics.
Vigorous Exercise Supports Cognitive Function and Mood
One area I pay particular attention to in my own approach to improving health span is preserving cognitive function, or brain health. Research abundantly shows that exercise may be one of the most powerful tools we have in decreasing the risk of cognitive decline. And in this context exercise intensity matters. More vigorous exercise offers more benefits to the brain.
I really enjoy exercise, and for me, measuring my heart rate or the thought of measuring my lactate level (which requires a small needle stick while exercising) takes away a lot of the enjoyment. So when I talk about vigorous exercise or high intensity, I like to go off of perceived exertion such as how long I can maintain that particular effort or how uncomfortably out of breath I feel.
There are more accurate ways of assessing your effort, whether using a heart rate monitor and calculating your maximal heart rate or using a lactate meter. For the purposes of this article I’m not going to get into the details of measuring exercise effort, but know that they are available and this is always something we can discuss if you’d like to use more precision in your training.
For this discussion, let’s define vigorous intensity as at least 75 to 85% of your maximal heart rate, or exercising to the point that breathing requires a bit of effort and holding a conversation would be unquestionable.
One big reason vigorous exercise particularly benefits brain health is the production of lactate (sometimes referred to as lactic acid). It used to be thought that lactate was just a metabolic byproduct that caused a burning sensation in the muscles or muscle soreness during hard efforts. But it turns out to be so much more. During normal activity and lower intensity aerobic activity, the mitochondria in our cells produce energy. But when you’re really pushing your muscles, at some point the mitochondria can no longer keep up with energy production and at that time a process called glycolysis starts to take over energy production outside of the mitochondria. This is where lactate is produced. (While not too important here, just for those of you who are curious, glycolysis is a set of biochemical reactions that allow glucose to be broken down for the production of energy, specifically creating ATP, under anaerobic conditions.)
So when our exercise requires more energy, or ATP, than our mitochondria can produce, which typically corresponds to when you feel you’re working to breath, then lactate is produced. Lactate can enter circulation and it serves as a fuel source for multiple organs, most notably the brain. In the brain, lactate is both a fuel and a signaling molecule. Lactate in the brain encourages the production of VEGF (vascular endothelial growth factor), which stimulates the production of new blood vessels along with repair of damaged vasculature. And lactate increases BDNF (brain-derived neurotrophic factor).
BDNF is a protein that benefits the brain in several ways:
Improving the survival and growth of new neurons (i.e., neurogenesis).
Increasing neuroplasticity, which is essential for learning.
Improving mood, or more specifically decreasing the risk of depression and anxiety.
So BDNF is definitely something we all want more of!
Vigorous Exercise Improves VO2 Max
In addition to supporting cognitive function, vigorous exercise may be your best option for improving VO2 max.
What Is VO2 Max?
Technically, VO2 max is simply the maximum rate of oxygen uptake by the body, measured in milliliters of oxygen consumed per kilogram of body weight each minute (ml/kg/min). A higher VO2 max indicates more efficient oxygen delivery to your muscles and equates to better cardiorespiratory fitness. So generally, a higher VO2 max is better than a low VO2 max, and there are references based on age and gender.
If you want to measure your VO2 max accurately, this can be done in certain labs or longevity clinics, and most often these tests are done on a treadmill or stationary bike while you wear a mask (so that the amount of oxygen inhaled and exhaled can be measured), working your way up to exhaustion. So not a lot a fun, and probably not necessary for most of us. There are simpler ways to estimate your VO2 max at home, such as the 12-minute run test, or Cooper test, but since I’m already trying to cover a lot here I will save that topic for another day.
Put succinctly, VO2 max is the best measurement of your cardiorespiratory fitness. And higher levels of cardiorespiratory fitness are correlated with lower all-cause mortality and lower risks of many chronic diseases including atherosclerotic cardiovascular disease and Type II diabetes.
So a higher VO2 max lowers mortality across the board, with no apparent upper limit (based on a study published in JAMA in 2018). This means that the fittest people, based on formal treadmill testing) had the lowest rates of mortality.
Overall VO2 max provides a reasonable assessment of our physical capability. Because maintaining quality of life is important when we think about health span, being able to preserve our physical capacity is extremely important. So maintaining our VO2 max, which naturally declines with every passing year, is essential. Because of the importance of VO2 max in predicting what we are able to do, or not do, in his book, Outlive, Peter Attia, MD suggests that we want to aim for a VO2 max in the elite level for your gender, but two decades younger. He acknowledges the ambition inherent in this goal, but given how much importance our cardiorespiratory fitness allows us to live independently, I think this is a worthy goal.
High Intensity Exercise May Also Decrease Aging
In case you are not yet convinced that it’s worthwhile spending a little time each week outside of your comfort zone with exercise, I’ll briefly discuss the role that vigorous exercise likely plays in decreasing cellular aging.
First, it’s important to understand that one cause of aging is cellular senescence.
What Is Cellular Senescence?
When our cells are exposed to any number of stressors, such as prolonged high blood sugar, excessive alcohol intake, poor sleep, obesity, and other causes of oxidative stress, they enter into a senescent state. In this senescent state the cells stop dividing, but don’t die, which has earned these cells the nickname “zombie cells.”
Cellular senescence provides a protective role to the body by preventing these damaged cells from becoming cancerous. But senescent cells, though no longer dividing, remain metabolically active, secreting inflammatory mediators, which can promote chronic low grade inflammation, and thus contributing to chronic diseases and signs of aging.
The particularly tricky thing about senescent cells, is that while they don’t become cancerous, they also are not readily cleared from the body. Thus with age, we have an accumulation of senescent cells. If you’ve heard about taking metformin, rapamycin, resveratrol, or fisetin for improving health span, these are all compounds being explored (with varying success) as potential senolytics (i.e., compounds that selectively kill senescent cells). (As a side note, of this short list, rapamycin remains the only compound that I think still holds potential as a senolytic, but marketing is still going strong on these other compounds despite a severe lack of evidence.)
Exercise As A Senolytic
Most of us already know, perhaps intuitively, several things we can do to decrease aging (i.e., decrease our burden of senescent cells):
Regular exercise
Maintain optimal body composition
Enjoy sufficient and regular sleep
Prebiotics and probiotics
Moderate intermittent fasting (I like to approach this by avoiding calorie intake two to three hours before sleep, which also improves sleep quality)
And since we’re exploring exercise here, let’s look at that particular intervention in a little more detail.
High intensity exercise, going above your aerobic capacity (again, exercising with an intensity that you can maintain for only 20 seconds to four minutes) will have a stronger effect on clearing out senescent cells when compared with moderate intensity or steady state cardiovascular exercise. Put in other words, vigorous exercise improves muscle tissue such that it appears to have a younger biological age.
This marked and favorable decrease in senescent cells after vigorous exercise is likely related to a few key physiologic changes that are unique to high intensity exercise. Specifically, high intensity decreases intracellular pH in the muscle (which relates to the lactate production discussed above), making the environment more acidic. This acidosis triggers the immune system, which brings certain immune cells into the muscle allowing a process of repair and growth (back to our concept of hormesis), and these immune cells promote clearance of cellular debris and senescent cells.
How To Bring Vigorous Exercise Into Your Routine
Exercise goals will be different for each of us. And if you’re just starting to bring more formal exercise into your routine, then starting small is always better. As a general approach, I like variety in my vigorous exercise, specifically using varying interval durations since different intensities (even within the high intensity category) engage different energy systems.
For example, once a week I like to include the Norwegian Protocol, or Norwegian 4x4, which includes four minutes at the maximal effort I can maintain for this time, followed by three minutes of rest, repeated four times. Another day I might include alternating one and two minute efforts with equal amounts of rest between each effort, repeated ten times. Some days I’ll include vigorous exercise as part of my strength training workout. This might include 30 second sprints on a treadmill at a 15% incline done between sets. Or this might include sets of heavy kettlebell snatches worked into a circuit.
Because high intensity intervals are demanding on the body, I have flexibility in how many times I include this type of exercise each week, and the total duration of vigorous effort. For example, during a week when I have a lot going on and might be feeling overwhelmed, I’ll likely include only one or two high intensity sessions. In a more typical week, when I’m feeling strong, then I’ll aim for three high intensity workouts within the week.
It’s good to listen to your body, but even though I genuinely enjoy exercise, even I sometimes have to nudge myself into starting a high intensity interval session. These are tough workouts, they will (and should) push us out of our comfort zones, but I hope I’ve provided you with ample reasons to starting nudging yourself to include some vigorous exercise to benefit your brain, your ability to live independently into old age, and to decrease your rate of aging.
*Medical Disclaimer: This article does not constitute as medical advice. Always consult with your physician before taking any steps to alter current treatment plans or begin new ones.