In less than ten years I ran 21 marathons. On top of enjoying the running friendships and fun destination marathons, I was convinced that the health benefits were undeniable. Then I started to hear about “the bell curve” in exercise. Clearly being a couch potato was bad for my health, but could excess exercise be equally dangerous?!? The research seemed to be saying that.
can i do too much exercise?
Palm Beach Marathon
On one hand we learn that aerobic exercise is good for our brains, cardiovascular system, and even reduces the likelihood of getting certain cancers. While on the other hand, we’re hearing things like, "White men who worked out approximately eight hours per week (or more) have double the risk of suffering from heart disease than white men who exercised less than two-and-a-half hours each week." Conflicted by the research, two years ago, I cut back in my running, and stopped running full marathons.
Just last week, on October 19, 2018, there was a study published in JAMA that might offer better clarity. This huge cohort study of over 122,000 patients looked at the relationship between aerobic exercise and long-term mortality, and clearly found that the higher the cardiorespiratory fitness the lower the likelihood of death from all causes...there was NO BELL CURVE! This study is notable due to its size and duration. Beyond the numbers of people studied and the length of the study, researchers used objective real measures instead of relying on patients self-reporting their exercise. This is a study that stands out when compared with previous studies, because it is “far more accurate and useful”!
Dr. Wael Jaber, a cardiologist at the respected Cleveland Clinic and senior author of the study, was not expecting these results, calling them "extremely surprising". It goes as far as finding that a sedentary lifestyle is worse for your health than smoking, diabetes and heart disease! In fact, when comparing the non-exercisers with the ultra-exercisers, there was a 500% higher risk of death in the non-exercising group! Yes…the study found that ultra-exercisers were not at higher risk of cardiovascular death, but that more was better, and that includes elite endurance athletes.
“There does not appear to be an upper limit of aerobic fitness above which a survival benefit is no longer observed.”
beyond cardiovascular, what are some key benefits:
Many controlled studies in elderly individuals have demonstrated that increasing our respiratory capacity through intense exercise results in the greatest improvement in cognitive performance. That no matter what stage, aerobic activity has been identified as the number one strategy to delay or avoid cognitive decline. Moderate activity can be beneficial, but high intensity exercise is better (more on exercise and the brain here and here).
Autophagy, literally "self-eating", is the process that helps to clear and use damaged cell parts, and as a result, promotes longevity through adaptation to changing conditions and stress. It plays a key role in preventing diseases such as cancer, neurodegeneration, diseases of the heart muscle, diabetes, liver disease, autoimmune diseases and infections. Exercise is an important strategy to increase autophagy in multiple organs (more on autophagy here).
Photo by Alexandra Dech on Unsplash
As we become physically stronger, we will feel better mentally. During exercise, our body releases endorphins, and serotonin which reduces stress and anxiety. Also by surpassing our fitness goals what we believe we are capable of accomplishing in other areas of our lives will begin to change, too. In fact, new research by University of Adelaide has found that the mental health impact of stopping exercise was seen almost immediately. Incredibly, depressive symptoms in some of the participants was observed after just three days.
Will i run another marathon?!?
Mark Sisson, from Mark's Daily Apple, points out that this study measured cardiovascular fitness (stress test), not hours spent training, so all we can say "for certain is that higher levels of cardio fitness predict greater longevity". We can infer that those with better cardiovascular fitness probably spent more time training to get it, but there are some other factors to consider, too.
His caution over "chronic cardio" isn’t about cardiovascular fitness; it’s a criticism of overtraining that results in people destroying their bodies. He argues, "you can train less and get better results, if you’re optimizing your recovery, nutrition, and sleep." Train smarter!
He also points out that it may not be the extremely high levels of training that leads to a longer life. Maybe those with the genetics to train long and hard would live longer even if they didn’t exercise.
It makes sense that we need to train smarter in order to maintain cardiovascular fitness over the years! So as I think about adding marathon’s back into my life, I can tell you this much…it won’t be four a year like I did at points in the past.
“You can train less and get better results, if you’re optimizing your recovery, nutrition, and sleep.”
Although this blog is focused mostly on aerobic exercise, there are huge benefits to strength training! This is also a generalization on the impact of aerobic exercise. The individual results are dependent on many factors, so it is important to talk to your doctor when making a plan to increase your health through adding any form of exercise. Finally, build the amount and intensity over time; too much too soon only invites trouble!
Wendy Dellis is a certified wellness coach. She joins years of training and work in the area of behavior change, experience as a fitness instructor and run club coordinator with a passion for adventure and people. She lives in Minnesota with her husband, Jay, and two sons.
Flying Pig Marathon to celebrate our 20th wedding anniversary!
The information contained on this page is for general information purposes only. Nothing here should be construed as medical or healthcare advice, but only topics for discussion. No physician-patient relationship exists; please consult your physician before making changes in diet or lifestyle.