#090 How Exercise Prevents & Reverses Heart Aging | Benjamin Levine, M.D.

Ben Levine on reversing heart aging: committed exercisers kept youthful hearts

Only those who exercised 4-5 days/week for 25+ years maintained youthful cardiac compliance.

"But let's suppose for a moment our goal isn't just to bail ourselves out at the absolute last minute with some type of Herculean effort. And instead, we ask ourselves what we should have been doing all along. What is the right routine to age best? From the start, Dr. Levine's research also looked retrospectively at the hearts of individuals based on their self-reported activity levels over 25 years. It was the committed exercisers alone, those who consistently exercised at least four to five days per week, who saw significant benefits in staving off the gradual increase in cardiac stiffening and heart shrinkage seen later in life. This highlights the importance of exercise as part of your personal hygiene and provides insight into how much we should be exercising throughout our life to maintain heart health."

The 2-year exercise protocol: HIIT, zone 2, and strength training combined

Levine's landmark study used Norwegian 4x4 HIIT, light aerobic recovery days, and strength training to reverse heart aging in previously sedentary.

"Participants engaged in a variety of exercises ranging from high intensity interval training sessions like the Norwegian four by four to light aerobic activity on recovery days and strength training."

Heart compliance as a biomarker: measuring cardiac stiffness with a catheter

Levine uses catheter-based pressure-volume measurements to assess how well the heart stretches and accommodates blood, a key marker of cardiovascular.

"The compliance or the ability of the heart to stretch and accommodate blood, not just the heart but the blood vessels also, is a marker of youthful cardiovascular structure."

Norwegian 4x4 for VO2max: 4 min at 95% max, 3 min recovery, repeated 4 times

Levine recommends the 4x4 protocol as the gold standard for improving aerobic power, where you go as hard as possible for 4 minutes with 3-minute.

"So the ideal strategy then is to incorporate all kinds of training. That's what the human body is best at adapting to. It doesn't really adapt very well to doing the same thing over and over and over again. You will not get fitter if you do that. And in fact, in our two-year training study, if you read below the lines a little bit, we markedly upscaled people. These were completely sedentary, and we worked them very hard for a year, including multiple high-intensity sessions, prolonged sessions. But then we said, all right, I want you to sustain that for a year. So we dropped them to only one interval session a week and one long session a week. And we didn't increase the dose, right? We didn't increase the frequency or duration or intensity over that last year. And you know what? They didn't get any fitter. And their hearts didn't get any bigger. The only thing that got bigger was the atria. And we can chat about that when we get to talking about toxicity of exercise training."

Exercise is cardiovascular hygiene, like brushing your teeth for your heart

Levine argues VO2max correlates with longevity partly because healthy people find it easier to exercise, creating selection bias in observational.

"So you brush your teeth twice a day because you don't want cavities. Well, you exercise because you don't want cardiovascular disease, right? I mean, there's other reasons you exercise too."

Lifelong exercisers sustain heart size but don't grow it indefinitely

Committed exercisers preserve their heart size and fitness over decades rather than progressively enlarging it.

"It's not that they're progressively getting bigger, they're sustaining and preserving their fitness and their heart size."

Endurance vs. strength training produce different cardiac adaptations

Endurance training causes the heart to dilate for greater stroke volume, while pure strength training thickens walls without dilation.

"A strength-trained athlete, the heart doesn't dilate, the walls just get bigger. It's the eccentric hypertrophy that's important for stroke volume and thus cardiorespiratory fitness."

Strength-only athletes should add endurance work for heart health

Pure strength trainers miss the eccentric cardiac hypertrophy that improves cardiorespiratory fitness.

"There are people that are much more focused on resistance training and strength training that are not athletes. They're just, you know, interested in health."

Central command vs. venous return: two mechanisms driving cardiac output in exercise

Exercise drives heart rate through central command during contraction and through venous return matching.

"That's why I mean it's no longer so simple to talk about just strength or just endurance."

CrossFit may produce both endurance and strength cardiac adaptations

CrossFit-style training that combines lifting with rowing, cycling, and rope jumping may produce both eccentric and concentric cardiac hypertrophy.

"Mike Emery from Cleveland Clinic now is a huge fan of the CrossFit-type training and believes that it will get you a combination of eccentric and concentric-type hypertrophy. And again, it's where this Morgan Roth hypothesis kind of falls apart because it's not one thing or the other. It's kind of a combination of both."

Heart rate zones explained: zone 2 is about 20 beats below lactate threshold

Levine defines zone 2 as ~20 bpm below lactate threshold (roughly 130-150 bpm) and explains that zone 4 "critical power" is the highest sustainable.

"Zone two training is about 20 beats below that, so 130 to 150."

Women may need less exercise volume for cardiovascular benefit before menopause

A JACC study suggested women need less exercise than men for the same benefit, but Levine attributes this to estrogen/progesterone protection.

"So it was like twice as less exercise, and they had the same cardiovascular. So I'm underwhelmed. I think that there's not a huge amount of benefit. The bottom line is that premenopausal women, they just don't have a lot of cardiovascular disease. There's extraordinary protection against cardiovascular disease by estrogen and progesterone."

Exercise does not remove arterial plaque but may stabilize it

The PRO@HEART study found more plaque in elite endurance athletes.

"It certainly provides protection, and it may against cardiovascular bad outcomes, and it may cause the non-calcified plaque to be more calcified and more rupture resistant. But I don't think it makes it go away. You know, there are idiosyncratic studies, you know, looking at, you know, this training and this reduction, but there's also idiosyncratic studies showing, you know, and, you know, Aaron Baggers showed in Run Across the America that when they did that, they had an increase in plaque."

Atrial fibrillation risk in endurance athletes and CHADS-VASC scoring

For middle-aged athletes under 65 with no other risk factors, the risk of blood thinners may outweigh stroke risk from atrial fibrillation.

"Unfortunately, there weren't a lot of elite athletes in the populations that developed that scoring system. So I don't know how perfect it is for a competitive athlete, but for a middle-aged athlete under the age of 65 with no other risk factors, no hypertension, no diabetes, no other heart diseases, the risk of anticoagulation is probably greater than the risk of stroke. You know, you have to say, well, you know, look, I'd rather take anticoagulation than have a stroke. You know, I'm willing to accept a little bit of a risk. That's a discussion to have with your doctor. Right. I want to be mindful of your time. I know you have to leave one quick question, life expectancy of what we would call this extreme type of endurance training. Yeah."