Nailing the Sweet Spot for Exercise Volume

STORY AT-A-GLANCE 1) If you’re sedentary and begin to exercise, you get a dose-dependent decrease in mortality, diabetes, depression, high blood pressure, coronary disease, osteoporosis, sarcopenia, falls and more. 2) People who are doing the highest volume of vigorous exercise start losing longevity benefits. If you’re doing full triathlons when you're in your 40s and 50s, your risk of atrial fibrillation increases by 500% to 800% 3) In the case of moderate exercise (loosely defined as exercising to the point where you're slightly winded but can still carry on a conversation) there’s clear evidence that more IS better and cannot be overdone. 4) Every 1,000 steps you get on average per day reduces your mortality by 10% to 15%. Benefits plateau around 12,000 steps (6 miles) a day. 5) Strength training adds another 19% reduction in all-cause mortality on top of the 45% reduction that you get from one hour of moderate exercise per day. However, benefits cease once you go beyond one hour per week. The sweet spot is 20 to 40 minutes of strength training, two to three times a week. Above 60 minutes per week, the benefits of strength training are nullified, and you’re worse off than if you did no resistance training at all. I interviewed Dr. James O'Keefe, a cardiologist with the Mid-America Heart Institute at St. Louis Hospital in Kansas City, about exercise dosing. He completed his cardiology training at Mayo Clinic. He and three other coauthors published a meta-analysis in the March-April 2023 issue of Missouri Medicine, the journal of the Missouri State Medical Association, which has profound implications. I view this study as a landmark that radically changed my views on exercise. Without a doubt, we need exercise. The question is, how much? Many of us who are committed to being optimally healthy tend to overdo it, which is certainly true in my case. Had I had the information in O’Keefe’s study earlier, I could have saved myself a lot of time and effort. Too Much Exercise Can Backfire As it turns out, O’Keefe also has a history, just like me, of overdoing it when it comes to exercise, which is ultimately what led him to pursue this research, trying to find out where the sweet spot is — the amount of exercise that delivers the greatest benefits. Do We Have Programmed Life Expectancy? O’Keefe recounts the story of how his mentor at the Mayo Clinic, decades ago, would admonish him when he’d go for a run at lunchtime saying "You know James, you're just wasting your heartbeats. Your heart has only so many heartbeats." His mentor made the case that everything appears to have a sort of programmed life expectancy that correlates with your heart rate. A hummingbird, for example, has a heart rate of 500 beats a minute and lives a year or two. The mouse has a similarly high heart rate and lives about two years. Animals with really slow heart rates, on the other hand, like the whale, can live 200 years. This is not to make a case for being a couch potato though. "It’s a complex math problem," O’Keefe says. What you want is to do enough exercise so that your pulse remains nice and low while you’re not exercising. Take-Home No. 1: Too Much Vigorous Exercise Backfires Big Time O’Keefe’s systematic review revealed that if you’re sedentary and begin to exercise, you get a dose-dependent decrease in mortality, diabetes, depression, high blood pressure, coronary disease, osteoporosis, sarcopenia, falls and more. So, most definitely, you can dramatically slow aging and improve life expectancy with exercise. However, at the very high end, the people who are doing the highest volume of vigorous exercise start losing those benefits. O’Keefe cites a recent large-scale study that followed about 1 million individuals for more than 10 years. While vigorous exercise up to 75 minutes per week reduced the risk of all-cause mortality and other diseases in a dose-dependent manner, benefits plateaued after that. So, people who were doing four to seven hours of vigorous exercise per week didn't get any additional benefit, "and probably, from a cardiovascular standpoint, lost a little bit," O’Keefe says. Take-Home No. 2: You Cannot Overdo Moderate Exercise In the case of moderate exercise, however — loosely defined as exercising to the point where you're slightly winded but can still carry on a conversation — it’s very clear that more IS better and cannot be overdone. Perhaps even more surprising, moderate exercise also improves all-cause survival better than vigorous exercise — about two times better. "If you look at the people who are doing the most vigorous exercise compared to the people doing the most moderate exercise, the moderate exercisers have twice as good a reduction in long-term mortality as the high volume vigorous exerciser," he says. What this means in practical terms is that: a) There’s no need to engage in high-intensity strenuous exercise beyond 75 minutes per week. Doing so can be highly counterproductive. If you’re an overachiever, stick to moderate exercise instead and your benefits will continue to accrue and your efforts won’t eventually backfire. b) Once you get into your mid-40s and 50s, exercise should be fun and stress-reducing, not competitive. In his analysis, O’Keefe also stresses the importance of "social exercise" over solo exercise: playing a game of tennis or pickleball with friends, for example. Several years ago, he conducted a study with colleagues in Copenhagen, Denmark, in which they looked at long-term data on physical activity and longevity. Playing tennis conferred 9.5 years of extra life expectancy; playing badminton got seven years; running, swimming and cycling were associated with just 3.5 years of extra life expectancy. Health club activities such as weightlifting and running on a treadmill only conferred 1.5 years of additional life expectancy compared to sedentary life. At first, O’Keefe thought the analysis had somehow gone wrong. But then he realized it was the social aspects of the sports that conferred the added benefits. What Big Data Tell Us About the Benefits of Walking Walking should not be underestimated either. The average American walks about 3,800 steps a day, which is just short of 2 miles. It’s about 2,000 steps per mile, and every 1,000 steps you get on average per day reduces your mortality by 10% to 15%, O’Keefe notes. Track Your Steps, but Beware of EMFs If you’re strapped for cash, you don’t need to invest in a special fitness tracker. Most cellphones have free activity trackers, so all you need to do is carry your phone with you. It’s not ideal due to the electromagnetic fields (EMFs) emitted, but you could put it in airplane mode. I recently gave a lecture at an autism event called Documenting Hope in Orlando. They’re committed to research and have invested hundreds of thousands of dollars to do detailed analyses of autistic children to identify the causes of autism. I almost fell off my chair when I heard the results. EMF was the No. 2 cause of autism. No. 1 was antibiotics, No. 3 was toxins, and No. 4 was vaccines. So, please, do take EMF exposures seriously. While adults aren’t going to develop autism from EMF exposure, it can still cause neurological damage. Take-Home No. 3: Overdoing Strength Training Is Worse Than Doing Nothing at All O’Keefe’s meta-analysis also detailed the sweet spot for strength training, and the results truly shocked me. I radically changed my exercise program after reviewing these data. Without question, strength training will improve muscle mass, muscle and bone strength. It can also boost your testosterone level if not overdone. It helps to improve mood and prevent falls. As you get into your 30s, you start to lose muscle mass and if you don't train to maintain muscle mass, you’ll eventually end up with sarcopenia (low muscle mass) or osteoporosis (low bone density). The benefit maxes out right round 40 to 60 minutes a week. Beyond that, you’re losing benefit. Once you get to 130 to 140 minutes of strength training per week, your longevity benefit becomes the same as if you weren't doing anything, which is nothing short of shocking. If you train for three to four hours a week, you actually end up with WORSE long-term survival than people who don't strength train! Recall, when you’re doing intense vigorous exercise in excess, you’re still better off than people who are sedentary. But for some (yet undetermined) reason, excessive strength training leaves you worse off than being sedentary. So, the take-home message here is that 20 minutes twice a week on non-consecutive days, or 40 minutes once a week is the sweet spot. You also don’t want your exercise regimen to center around strength training. It should be an add-on, as you get far greater benefits simply from walking, or any other moderate exercise. Get Your Nature Fix O’Keefe’s paper also discusses the benefits of spending time in nature. A British study cited found you need at least 1.5 to two hours outdoors each week for good health, even if it’s only a local park or tree-lined street. The Sit-Rise Test Lastly, we review a simple clinical assessment that gauges nonaerobic components of fitness — strength, balance and flexibility — skills that undergird long-term survival. It’s called the sitting-rising test (or sit-to-stand test). To perform this test: a) Standing, cross your feet at the ankles b) Squat down until you’re sitting cross-legged on the floor c) Raise yourself back up to standing The object of the test is to sit down and stand back up using as few supports as possible. A perfect score of 10 — 5 points down and 5 points up — is obtained if you can squat down and stand back up without using your hands, elbows or knees for added stability or support. For each body part that touches the floor — a hand, forearm, elbow, knee or side of the leg — either on the way down or up, deduct 1 point. This test has been shown to be remarkably accurate for predicting longevity. Having a score of 8 to 10 means you have a very low risk of dying within the next 14 years while a score of 0 to 3 is associated with six-fold higher all-cause mortality. As noted by O’Keefe, the ability of this test to predict survivability "speaks to the fact that fitness is a multifaceted thing and you need to work on all those different things," meaning balance and flexibility, in addition to aerobic exercise and strength training. Source: mercola.com, 11/26/23.