Ep. 47 – Is less more when it comes to exercise?
I'm sure that you've heard of the expression less is more. Could less exercise than we've been taught actually reduce the risk of cardiovascular disease and hypertension? Sounds all wrong but Dr. Chet Zelasko will tell you what he found out on this edition of Straight Talk on Health
Welcome to Straight Talk on Health. I’m your host Dr. Chet Zelasko. Straight Talk on Health is recorded in conjunction with WGVU in Grand Rapids MI. I examine the world of health. Whether it’s research that makes the news, another miracle diet, or a new food fad, I look at the science behind them, and let you know whether it’s real or not. You can check out other things that I do on my website Drchet.com and sign up for my free emails.
I've had a PhD in exercise physiology and nutrition for 35 years. In that time, I've seen no real increase in the number of people who exercise on a regular basis. It was about 15-20% then and it’s about the same today.
There are several different objectives for exercise. We have the people who love competition. We have the people who strive to use exercise as a way to look good and maintain whatever their vision of fitness is. But then the majority of people, I would estimate it being over 80%, are simply interested in reducing their risk of disease. With the guidelines that are currently in place, I think it seems overwhelming to many people. I t may be because they don't like to sweat. It may be because they don't want to invest the time because their lives are already overbooked. Maybe they don't realize that there are no hard and fast rules for how much we need to exercise because something is better than nothing. Recent research may help understand that better.
Let’s review the recommendations about exercise from the CDC, and just about every medical society that exists, not only in the United States, but in the entire world.
Moderate-intensity aerobic activity such as brisk walking for 150 minutes every week, for example, 30 minutes a day, 5 days a week) and Muscle-strengthening activities on 2 or more days a week that work all major muscle groups (legs, hips, back, abdomen, chest, shoulders, and arms).
Vigorous-intensity aerobic activity such as jogging or running for 75 minutes every week and muscle-strengthening activities on 2 or more days a week that work all major muscle groups, which are again, legs, hips, back, abdomen, chest, shoulders, and arms.
One can also use a combination of moderate and high-intensity aerobic exercises per week in addition to the strength training activities.
What was the first thing that crossed your mind when you heard the guidelines? Was it about time commitment? Was it about the effort required? Was it that you didn’t understand the exercises that qualify? Was it that you don’t know much about weight training? Put all those aside.
This podcast as well as the next one are going to focus on the health benefits of exercise by investing a minimal amount of time, equipment, and effort. and let’s look at some research. This is not an attempt to get you super fit. It is an attempt to get you doing something that recent research shows may impact your health and longevity.
Using recently published studies, we're going to develop a reasonable exercise program that takes the least amount of time. And we're going to start with, of all things, isometric exercise because it caught me by surprise. Let's turn to the research.
Researchers conducted a literature search of all published studies that examined the impact of any type of exercise on systolic (SBP) and diastolic blood pressure (DBP.) They conducted a pairwise and network meta-analysis to see which exercise helped BP the most. That sounds so fancy but what it really means is that pairwise is comparing 2 variables while network is comparing more than two variables in the analysis. The most important finding was that every form of exercise significantly reduced SBP and DBP when performed for 2 weeks and longer: aerobic exercise training, dynamic resistance (weight) training, combined training, high-intensity interval training (HIIT), and isometric exercise training.
When they compared the efficacy of every form with each other, isometric exercise lowered SBP the most, followed, in order, by combined training, weight training, aerobic training, and HIIT.
To me, isometrics are somewhat easy to perform because it removes obstacles like orthopedic issues, equipment, and other things. But why would it reduce BP more than other modes of exercise?
If you have a home BP monitor, try a little experiment on yourself when you’re done listening or pause the podcast and try it now, as long as you’re not driving your car. Set up your monitor and cuff and sit quietly in a chair. After 5 minutes or so, take a deep breath, exhale, and hit the Start button on the monitor while breathing normally as your BP is taken. Record the results. Make sure the cuff deflates completely and continue sitting for another 5 minutes.
Then, repeat the deep breath, exhale, and hit the Start button. This time, I want you to contract the muscle in the opposite arm as much as you can and hold the contraction until the BP is done, breathing normally the entire time. Do you notice a difference in the BP without and with contracting your opposite arm? Unless you lift heavy weights on a regular basis, you should.
When you contract the opposite arm, you are restricting blood flow to that arm, thereby increasing the resistance. When you relax, there should be an increase in blood flow to that tissue. When you do isometric exercises regularly, that’s what happens in every muscle group you do isometrics with.
Let’s return to the study. The researchers did a secondary analysis to see if they could find the exercise that lowered BP the most. The wall-chair worked best to lower SBP while running lowered DBP the most.
What’s the wall-chair? The idea is to stand a foot or so from the wall, lean back until your back contacts the wall, and slide down to a sitting position for 5-10 seconds, then slide back up. Repeat 10 times up to several times per day. The key is to never hold your breath while you do it. The quadriceps and the gastrocnemius are a substantial amount of muscle. Restricting blood flow with isometrics will increase the resistance on the heart and blood vessels. The benefit is that you will get a training effect on both that lowers BP.
What’s actually going on with the nervous, CV, and muscle system isn’t quite clear but knowing that won’t help you do them. If you don’t have orthopedic issues, and again, you don’t hold your breath while performing the isometrics, no matter what muscle groups you use, you may help your lower your BP. I think the wall-chair works the best due to total muscle mass involved but every muscle group will help. If you want another isometric look no further than the plank from yoga. Move up to plank position, hold for 5-10 sec while breathing, return to the floor. Same deal as the wall-chair in terms of reps and sets. In this case, you’re contracting every muscle from your arms, especially your core, down to your legs.
Will isometrics make you super fit? No. Super strong? No. There are also limitations as to the angles where strength will increase due to specificity of training. But there seems to be an emphasis on improving health with short episodes of exercise. Isometrics fit that niche quite well and as the study demonstrated, quite effectively as related to BP. In the next episode, we’ll look at studies on exercise that can benefit your CV system. Until next time, this is Dr. Chet Zelasko saying health is a choice. Choose wisely today and every day.
Reference: British J Sp Med Online July 2023. doi: 10.1136/bjsports-2022-106503