Physical fitness more important than losing weight in heart disease
The development of cardiovascular disease has a causal relationship with obesity. Despite this strong correlation, the results from major meta-analyses indicate that people with cardiovascular disease who have a body mass index (BMI) above the normal weight range have better prognoses. This is often called the obesity paradox.
"What we've known for a while is that for heart patients it seems to be an advantage to be fat - the so-called obesity paradox. But although it seems like it pays to be overweight and that weight loss affects these patients adversely, all of these data are based on observational studies. To prove causality, randomized controlled trials are needed," says Moholdt.
- The heart disease patients can gain weight without jeopardizing their health, but sitting in their recliner incurs significant health risks.
- During the 30-year period, 1493 of the participants died and 55 percent of the deaths were due to cardiovascular disease.
- Weight loss seems to be associated with increased mortality for the participants in the study who were normal weight at baseline.
- Weight loss, classified as a change in BMI <–0.10 kg/m2/year, associated with increased all-cause mortality.
- Weight gain, classified as a change in BMI ≥0.10 kg/m2/year, was not associated with increased mortality.
- There was a lower risk for all-cause mortality in participants who maintained low PA or high PA, compared with participants who were inactive over time.
- The risk of premature death was higher for the group of patients who were completely inactive than for either of the other groups.
The recommended activity level is at least 150 minutes per week of moderate physical activity or 60 minutes per week of vigorous physical activity.
"The clinical guidelines for heart disease patients currently include having a normal weight and being physically active. I would put more emphasis on the exercise aspect. When it comes to physical activity, you have to do what gets you in better shape. That means training with high intensity. Do something that makes you breathe hard so that it's hard to talk, but not so hard that you can't do it for four to five minutes," says Moholdt. She adds that heart disease patients are often in poor shape, so it often doesn't take much to get into the high-intensity mode.
When asked whether any of the study results were unexpected, Moholdt said that they weren't surprising in terms of physical activity. "But the fact that gaining weight posed no increased risk when patients were already overweight, I think is a bit surprising," she said.
The results indicate that weight gain does not seem to increase the risk for already overweight patients, which would mean that it isn't dangerous for a fat heart patient to gain a few pounds. What is dangerous is if the person does not engage in any form of exercise.
This study's results do not mean that it is never a good idea for an overweight heart patient to slim down. Moholdt and her colleagues note in their JACC article that "in our view, desired or intentional weight reduction may be useful for overweight or obese individuals, although little data supports this view in studies of coronary heart disease patients."
The hypothesis was that the weight loss is associated with improved survival among overweight and obese coronary heart disease patients but this correlation was not evident in the study.
"Exercise has a beneficial effect on all organs in the body - on the brain, heart, liver, vascular system and of course on our musculature," she says.
The relationship between BMI and life expectancy is complicated and depends on several factors. Erroneous sources are plentiful. Results from another analysis showed that normal weight, healthy non-smokers have the lowest risk of premature death.
Based on the study, the authors concluded that no mortality risk reductions associated with weight loss in individuals with CHD, and reduced mortality risk associated with weight gain in individuals who were normal weight at baseline. Sustained PA, however, was associated with substantial risk reduction.
For more information click on the link: https://doi.org/10.1016/j.jacc.2018.01.011