When we engage in high-intensity exercise, our muscles become mini biochemical laboratories, synthesizing compounds like lactate and myokines that circulate throughout the body and travel to our organs, where they exert a variety of signaling effects, including the synthesis of brain-derived neurotrophic factor (BDNF) in the brain. Some of these molecules have anti-cancer properties.
Vigorous exercise is also the most potent way to increase your VO2 max, also known as cardiorespiratory fitness, which is one of the strongest predictors of longevity. Essentially, the higher your fitness, the longer you’ll live.
Why intensity of exercise matters.
High-intensity exercise has certainly received its share of the spotlight, in large part thanks to researchers like Dr. Martin Gibala who has helped to establish the wide-ranging benefits of HIIT on metabolic health, cardiovascular health, and fitness.
Yet the longevity space has recently focused on low-to-moderate intensity aerobic exercise, or so-called “zone 2 training”, for promoting health and longevity. In contrast to high-intensity exercise, zone 2 training prioritizes fat burning and is performed for a longer duration at a lower heart rate.
Then there are exercise snacks and vigorous intermittent lifestyle physical activity or VILPA—which aren’t really exercise in the classic sense. Rather, they’re brief, higher-intensity bouts of physical activity performed several times throughout the day. Even though less research has been devoted to investigating the benefits of exercise snacks and VILPA, they’re consistently associated with better fitness and metabolic health.
All of this begs the question: With so many types of exercise out there, what should we be doing to live longer?
Does frequent HIIT promote the most robust improvements in longevity? Or is low-intensity and long-duration zone 2 training the better option? If we only engage in short, frequent bouts of VILPA or exercise snacks, can we still reduce our risk of disease?
This is hard to answer since it would require performing a head-to-head comparison in large groups of people for several decades. As informative as that would be, it’s not a very feasible research study.
What we have to rely on are reports that establish an association between the types of activities people perform and their risk of dying.
That’s what was done in a recent study, where It was revealed that physical activity intensity, rather than volume, appeared to be the main driver of reduced mortality risk. In fact, when it came to the risk of dying from cardiovascular disease, only physical activity intensity stood out as an important factor—physical activity volume wasn’t associated with a lowering of cardiovascular disease mortality.
There were a handful of other findings worth mentioning that I think have important implications for health and longevity. So let’s explore the study a bit further.
|
|
|
You just missed this in your inbox
Every week, Dr. Rhonda Patrick and the FoundMyFitness team distill the latest research into clear, actionable insights on health, longevity, and performance, delivered free to your inbox.
Intensity outshines volume
The volume and the intensity of physical activity were associated with all-cause mortality risk—engaging in more volume or more intense exercise reduced one’s risk of all-cause mortality. However, the effect of intensity was stronger.
The risk of all-cause mortality was 37.1% lower for participants with levels of high-intensity activity at the midpoint of the population compared to those in the lower 25%. The risk decreased by 19.8% when comparing participants at the midpoint of high-intensity activity to those in the upper 25%.
For physical activity volume, all-cause mortality risk was reduced by 14.4% and 13.7% when comparing the lower 25% to the midpoint and the midpoint to the upper 25% of participants, respectively.
The results for cardiovascular disease mortality revealed something very interesting and, to me, surprising.
Just like for all-cause mortality, more high-intensity activity was associated with a lower risk of cardiovascular disease mortality—a 41% reduction and a 29.8% reduction when comparing the lower 25% of participants to the midpoint and the midpoint to the upper 25%, respectively.
On the other hand, there was no association between physical activity volume and cardiovascular disease mortality—doing more did not seem to provide a benefit.
|
|
|
| |
Longer activity bouts are beneficial
The importance of intensity for mortality reduction has been established. But how does the pattern of activity factor in?
At any level of intensity, there were greater benefits for all-cause and cardiovascular disease mortality when activity was accumulated in bouts of 5 minutes or more compared to more fragmented bouts of less than 5 minutes.
Let’s take a minute to put this into perspective. Let’s say that you engage in 30 minutes of high-intensity activity per day. You’re much better off (from a mortality perspective) doing three 10-minute activity bouts than ten 3-minute bouts. More exercise snacks, less VILPA.
Yet again, the pattern or fragmentation of physical activity didn’t appear to be as important for volume: Bout length was not significantly associated with all-cause or cardiovascular disease mortality. There was no difference in the benefits of doing more low- and moderate-intensity exercise in bouts of 5 minutes or less or more than 5 minutes.
|
|
|
|
|
HIIT it to live long
There’s an easy way to explain these results if we think about the myriad benefits of vigorous exercise—it’s overall better for improving blood lipids, glucose regulation, cardiac function, and inflammation and oxidative stress compared to less-intense exercise. So even though exercise volume is important, exercise intensity is what really leads to physiological improvements that can enhance health and longevity.
This is especially apparent when it comes to the heart and might explain why, at least in this study, exercise intensity, but not volume, was associated with a lower cardiovascular disease mortality risk.
If you’re not exercising hard enough to stress your heart, muscles, and brain, it doesn’t matter how much you do after a certain point.
According to this study, all of your vigorous exercise should be completed in bouts of 5 minutes or more. But I’m not completely convinced that there aren’t benefits to engaging in shorter bouts.
That’s because of the strong evidence in favor of VILPA (remember that VILPA refers to ~1–2 minute bouts of vigorous activity done as part of daily life) for reducing mortality risk. Just 3 VILPA bouts per day reduces all-cause mortality by up to 40%. This inconsistency might just reflect the different ways in which physical activity bouts were characterized in the VILPA studies compared to this large cohort study. Nonetheless, I think there’s a good reason to make sure you’re engaging in at least a few longer-duration bouts of vigorous exercise each day and multiple times per week—just to be safe. Exercise snacks and VILPA probably shouldn’t make up the foundation of your aerobic exercise training despite their massive health benefits.
|
|
|
|
Final thoughts
All discussions on exercise eventually boil down to one conclusion: You need to do a variety of low-, moderate-, and high-intensity training every week.
This study is not proof that we should only be doing intense exercise because it’s better for reducing all-cause and cardiovascular disease mortality. That’s not the message I want you to take away today.
Rather, the results reinforce how important, or rather, how necessary vigorous exercise is for longevity.
Just doing zone 2 training isn’t going to cut it if your goal is optimizing healthspan and lifespan. This is especially true for the people who might dedicate very little time each week to cardiovascular training—more intense is better overall in an absolute sense in this scenario.
Vigorous activity—which stresses the body and stimulates the brain—is one of the strongest longevity-promoting tools that we have at our disposal. It’s not “easy” to do in the physical sense, but it’s perfectly simple.
Go hard, rest, repeat, and your health will thank you.
For more on high-intensity exercise, aerobic fitness, and longevity, check out member Question & Answer Session #53.
|
|
|
|
|
|
Relevant timestamps related to exercise and longevity:
-
01:08:12 - How do you measure your VO2 max regularly and what is an ideal mix of zone 2 and interval training?
-
01:09:05 - How to use the 12-minute run test to estimate VO2 max
-
00:10:30 - The formula for estimating VO2 max using results from the 12-minute run test
-
01:10:55 - What is the ideal split of high- and low-intensity training?
-
00:11:05 - How much vigorous exercise should someone training less than 10 hours a week be doing?
-
00:11:20 - What are the benefits of high-intensity exercise other than improving VO2 max?
|
|
|
|
With appreciation,
Rhonda and the FMF Team
|
|
|
|
|
