Researchers at the Cleveland Clinic1, a non-profit academic medical center in Cleveland, Ohio, retrospectively studied 122,007 patients who underwent exercise treadmill testing at the clinic between Jan. 1, 1991, and Dec. 31, 2014, to measure all-cause mortality relating to the benefits of exercise and fitness.
Researchers at the Cleveland Clinic1, a non-profit academic medical center in Cleveland, Ohio, retrospectively studied 122,007 patients who underwent exercise treadmill testing at the clinic between Jan. 1, 1991, and Dec. 31, 2014, to measure all-cause mortality relating to the benefits of exercise and fitness.
The study found that increased cardiorespiratory fitness was directly associated with reduced long-term mortality, with no limit on the positive effects of aerobic fitness. Extreme aerobic fitness was associated with the greatest benefit, particularly in older patients (70 and older) and in those with hypertension.
“Aerobic fitness is something that most patients can control. And we found in our study there is no limit to how much exercise is too much,” said Wael Jaber, M.D., Cleveland Clinic cardiologist and senior author of the study. “Everyone should be encouraged to achieve and maintain high fitness levels.”
Several recent studies have suggested associations between extreme exercise and certain adverse cardiovascular findings, such as atrial fibrillation and coronary artery disease. However, the researchers in this study found that extreme fitness provided additional survival benefit over more modest levels of fitness, and that extremely fit patients lived the longest.
“We were particularly interested in the relationship between extremely high fitness and mortality,” said Kyle Mandsager, M.D., an electrophysiology fellow at Cleveland Clinic and the lead author of the study. “This relationship has never been looked at using objectively measured fitness, and on such a large scale.”
All patients had previously undergone stress tests at Cleveland Clinic and were broken up into five performance groups – elite, high, above average, below average and low. Elite performers were defined as having aerobic fitness in the top two and a half percent by age and gender and demonstrated fitness levels comparable to endurance athletes.Long-term survival was adjusted for a patient’s age, sex, height, weight, BMI, medications, and comorbidities (the simultaneous presence of two choice diseases or conditions).
When the subgroups were analyzed by age, the survival benefit of elite versus high performance was most notable in older patients. In those over the age of 70, elite performers had a nearly 30 percent reduced risk of mortality compared to high performers. In younger age groups there was no statistical difference in outcomes between elite and high performers.
When the subgroups were analyzed by comorbidities, all-cause mortality inversely related to cardiorespiratory fitness and were lowest in the elite performers. For those patients with hypertension, the elite performers again showed a nearly 30 percent reduction in all-cause mortality compared to high performers. For all other comorbidity subgroups, there was no statistical difference in survival rates between the elite and high performers.
Do Not Over-Science, Bro
It is important to note that the study analyzed findings over a large population and provides a statistical analysis of the relationship between aerobic fitness and mortality meaning it doesn’t necessarily apply to everyone.
It’s always worth noting that cohort studies, like this, give researchers some shape to data and provide models that determine parameters for future studies, but they don’t apply to everyone. You might be extremely fit, have some chronic disease and be subject to none of the benefits, unfortunately. Or, you may be very unfit by the measures of this study, and it has no impact on your longevity.
There are also other factors associated with extreme fitness that this study does not address such as the impact on one’s joints, for example. It might be best left said that aerobic fitness is a good thing, and a very good thing as you age so, keep pushing within reason – that’s what matters most.
There is a point beyond which, you could argue, the more aerobic fitness you have, the less impactful the result may be even though there is some impact, meaning a sort of diminishing return. Again, it’s a statistical model that uses a large data set to arrive at some helpful conclusions, but shouldn’t be read as black and white gospel on where your mortality is headed.
Reference:
1. Kyle Mandsager, Serge Harb, Paul Cremer, Dermot Phelan, Steven E. Nissen, Wael Jaber. Association of Cardiorespiratory Fitness With Long-term Mortality Among Adults Undergoing Exercise Treadmill Testing. JAMA Network Open, 2018; 1 (6): e183605
