Nonalcoholic fatty liver disease (or NAFLD) is a lifestyle disease that is caused by an unhealthy diet, obesity, and a lack of physical exercise.
And it can be fought off with improved diet and exercise.
But how much do you have to change your lifestyle to fight or reverse it? And when have you done enough?
A new study in the Journal of Gastroenterology and Hepatology gives a very clear answer to these questions.
The authors split the question into two parts: how much exercise should you do per week and how fit should you be?
They recruited a sample of 7,111 adults who had no history of liver dysfunction and then scanned their livers to check for NAFLD. They found that 28.3% of the men and 6.5% of the women were afflicted by this.
They obtained other demographic and health information, including (importantly) the number of minutes that their subjects exercised per week and the vigor level of this exercise. The researchers used this information to divide these volunteers into low, moderate, and vigorous physical exercise groups.
To obtain their cardiorespiratory fitness levels, the scientists asked the participants to exercise on a treadmill while their heart rate, blood oxygen, and breathing rate were measured. Based on their fitness levels, they were divided into quintiles 1 to 5, with 1 being the least fit and 5 the most fit.
With all of this information at hand, the researchers could draw some definitive conclusions:
- 1. People who exercised 60 minutes or more per week had the lowest risk of NAFLD—42% lower than those who did not exercise at all.
2. Only vigorous exercise reduced the subjects’ NAFLD risk, while light and moderate exercise did not.
3. The participants’ NAFLD risk declined with increasing fitness levels. Compared with quintile 1 (the least fit), those in quintile 2 had a 39% lower risk while those in quintile 5 had a 51% reduced risk.
4. The relationship between cardiorespiratory fitness and NAFLD was stronger than the relationships between NAFLD and either the amount or vigor of exercise.
And since the fitness level mattered most of all, it’s also important to improve your diet and other lifestyle factors to improve your overall fitness level.
This doesn’t mean that you have to do vigorous daily exercise to avoid NAFLD—the more important thing is to increase your cardiorespiratory fitness to the max.