Why Poor Cardio Fitness Might Be Even More Deadly Than Smoking


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Heading out on a long ride might just help you live longer: People with high aerobic fitness levels tend to live longer than those who are more modestly fit, researchers from the Cleveland Clinic found.

In the study, researchers analyzed treadmill stress-test data from over 120,000 participants with an average age of 53 to determine their cardiorespiratory fitness, which was based on treadmill grade and peak speed during the exercise. They place them into one of five categories: low, below average, above average, high, and elite based on their MET score, or their metabolic equivalent of a task.

Then, the researchers followed up the participants for an average of eight years. They discovered that the people in the elite level of cardiorespiratory fitness—those who scored at or above the 97.7th percentile in the test—were 80 percent less likely to die during follow up than those in the poorest fitness level group, meaning they scored in the lowest 25th percentile of aerobic fitness.

For perspective, the elite group averaged 13.8 METs, compared to 6.1 for the low group (For comparison, riding between 16 to 19 mph would be 12 METs, and a leisurely ride at 10 to 11 mph would be 6 METs.

The study’s findings suggest that the more fit the you are, the less likely you are to die early—there was no observed upper limit of benefit to higher fitness, study author Kyle Mandsager, M.D., cardiologist and cardiac electrophysiology fellow at the Cleveland Clinic, told Runner’s World.


“Previous studies have relied on self-reported activity levels, which are often inaccurate, and this may explain why we did not see the ‘plateau’ effect which has been seen in [other] studies,” said Mandsager.

The risks of being the least fit, when compared to the most fit, are markedly worse than smoking.

Still, you don’t necessarily need to be at the elite fitness level to reap the live-longer benefits. For each step up in aerobic fitness level, the survival benefits increased by 25 to 50 percent.

What’s more, the negative health effects of having a poor fitness level were pretty similar to those of known lifespan reducers, like smoking, diabetes, and heart disease. In fact, the risks of being the least fit, when compared to the most fit, are markedly worse than smoking, diabetes, or heart disease.

“That’s important, since many people may not know that poor fitness is as problematic for our health as those conditions,” said Mandsager.

So how might high fitness levels lead to a longer life? “Exercise has been associated with innumerable health benefits, including reduced risks of heart attack, stroke, high blood pressure, diabetes, obesity, and even cancer,” Mandsager said.

Bottom line: As the study shows, the more fit you are, the more likely it is that you’ll avoid a premature death. While the current guidelines from the American College of Cardiology and American Heart Association recommend a minimum of 150 minutes of moderate activity (such as brisk walking), or 75 minutes of vigorous aerobic activity (such as riding or interval training) per week, Mandsager said the study results suggest a greater benefit the fitter you become.

So work on improving your fitness—and make it a lifelong goal. That’s super important, since the results in the study were particularly striking in older patients.

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