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Exercise in non-alcoholic fatty liver disease

Introduction Non-alcoholic fatty liver and in some cases steatohepatitis (which is an inflammation form of NAFLD) are very common non-communicable diseases. Usually those were associated with diabetes and with adult population but in recent decades the prevalence increases among non-diabetic and young population, even adolescents. The most serious complication of the disease is the development of liver cirrhosis and malignant liver disease. There is a strong link between the fatty liver disease and the peripheral insulin resistance so for that reason this condition is very often seen in diabetes, prediabetes or in metabolic syndrome. The kinesiology scholars are becoming more and more interested in this problem, as it seems that physical exercise might significantly improve the condition. The most interesting fact is that it also seems that the condition might be improved by exercise regardless of the change in body weight. Even though that a change in weight of 10% might significantly improve the condition, that reductions is rarely achieved. That is why the exercise comes in focus even more. Exercise benefits in NAFLD The exercise benefits might be observed through reduced inflammation, reduced liver enzyme concentrations, decreased hepatic lipid content and improved insulin resistance, depending on the study. There is still no consensus about which exercise modality, type, volume or frequency provides the greatest benefits so in future more studies are needed. Nevertheless, some evidence implies that the needed intensity might be relatively high as in some studies only those meeting vigorous exercise intensity of over 7 METS experienced significant improvements. The effects of the resistance training were studied in a lesser extent than the effects of the aerobic activity but with some promising results. It seems that a significant reduction of liver fat content might be achieved in 8 weeks of resistance training. That is especially important as proinflammatory state in hepatosteatosis induces sarcopenia, which should be counteracted with strength training and adequate nutrition. In a progressed liver disease, like cirrhosis, the vigorous intensity may not be applied. The reason for that is the role of liver in lactate removal cycle. Also, ammonia removal by liver might be impaired in cirrhosis, but muscles might be an important alternative detox route in preventing hepatic encephalopathy. Recommendations In conclusion, an exercise regime improves clinical outcomes of chronic liver disease, maybe through autophagy, and it seems the best effects in are achieved with moderate, even vigorous intensity. The current recommendations for NAFLD might be as follows: the start of the program should be graduate with frequency of aerobic exercise of 4-5/wk, intensity 5-6 on Borg 1 to 10 RPE scale, corresponding to 75-80% of HRmax for most patients and maintaining the ability to talk. The strength training should be incorporated 2-3/wk, at 60-70% of 1 RM and higher number of repetitions (10-15), aiming to reach 3 sets per exercise and 7-8 exercises/ session. The breaks between sets should be longer than 1 min in order to reestablish circulation. The flexibility regime should always follow the strength training session. In case of liver cirrhosis and increased portal pressure the regime should be adjusted. References Chalasani N, Younossi Z, Lavine JE et al. (2012). Hepatology, 55(6):2005–23. Hallsworth K, Fattakhova G, Hollingsworth KG, Thoma C, Moore S, Taylor R, Day CP, Trenell MI. (2011). Gut ; 60(9):1278–83 Locklear CT, Golabi P, Gerber L, Younossi ZM. (2018).Medicine (Baltimore), 97(42):e12774. Takahashi H, Kotani K, Tanaka K, Egucih Y, Anzai K. (2018). Front Endocrinol (Lausanne). 15 ; 9:588. Zou TT, Zhang C, Zhou YF, Han YJ, Xiong JJ, Wu XX, Chen YP, Zheng MH. (2018). Eur J Gastroenterol Hepatol, 30(7):747-755.

NAFLD ; exercise

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