A new study at University of California San Francisco has revealed that non-alcoholic fatty liver disease (NAFLD) may lower cardiovascular fitness, muscle strength, body composition and physical fitness.
NAFLD is fatty inflammation of the liver related to insulin resistance and the metabolic syndrome. It is the most common cause of abnormal liver enzymes.
However there is little known about the relationship between fitness and NAFLD severity.
During the study, lead researcher Joanne Krasnoff of the University of California San Francisco examined 37 adult patients with a spectrum of NAFLD severity as measured by liver biopsy.
The findings revealed that across the spectrum of NAFLD severity, patients had suboptimal cardiorespiratory fitness, muscle strength, body composition and physical activity participation.
The team also found that more than 97 percent had a body fat percentage that put them at increased risk for morbidity and mortality.
The study exhibited lower cardiorespiratory fitness in subjects with increasing NAFLD severity.
"This provocative finding raised the question of a cause-or-effect phenomenon-does cardiorespiratory fitness attenuate NAFLD or does increasing NAFLD severity result in a decline in cardiorespiratory fitness?" wrote the authors.
"Despite our study limitations we believe the objective demonstration of low cardiorespiratory fitness and muscle strength with a high incidence of obesity illustrates the potential clinical relevance of these measures both before and after interventions," they added.
However the authors suggest that lifestyle interventions can help in slowing the disease progression.
"It would appear rational and prudent for healthcare providers to recommend exercise training to improve health-related fitness as an integral role in the care of patients with NAFLD," they said.
The study appears in the April issue of Hepatology, a journal of the American Association for the Study of Liver Diseases (AASLD).