Liver Disease And Physical Activity

Liver disease is a condition of global concern. This is because it has potentially devastating consequences, and its prevalence is currently on the rise. As major causes of death globally shift towards non-communicable and degenerative diseases, liver disease prevention becomes imperative. Studies have shown that physical activity can preserve adequate liver function and prevent liver disease.

What is liver disease?

There are many different types of liver disease and some of the common ones are:

Alcohol-related liver disease (ALD)

The symptoms of ALD are not apparent until very late stages when the liver is severely damaged. ALD is caused by alcohol abuse and there are 3 stages to it: 

1. Alcoholic fatty liver disease is caused by fat accumulation in the liver as a result of alcohol abuse. Although the disease does not cause physical symptoms, alcoholic fatty liver can be a sign of alcohol excess. The effects of fatty liver disease are reversible with time and alcohol abstinence.
2. Alcoholic hepatitis is a result of inflammation of the liver caused by excessive alcohol consumption. While mild alcoholic hepatitis is reversible, severe alcoholic hepatitis is a serious condition and can be life-threatening. 
3. Cirrhosis is a stage where the liver is profoundly damaged. While the disease is irreversible, cessation of alcohol consumption could increase life expectancy and prevent further liver damage.¹

Non-alcoholic fatty liver disease (NAFLD)

NAFLD is caused by an accumulation of fat in the liver as a result of a sedentary lifestyle and excessive calorie intake. It is closely associated with an increased risk of metabolic syndrome - hypertension, obesity, and diabetes mellitus. There are 4 stages of NAFLD. These are:

1. Steatosis or simple fatty liver is a condition where large amounts of fat build up in the liver.
2. Non-alcoholic steatohepatitis (NASH) is a more serious stage where the liver has become inflamed.  
3. Fibrosis is the scarring of the liver as a result of persistent inflammation. However, at this stage, liver function is still somewhat preserved. 
4. Cirrhosis occurs after long-term inflammation. The liver is permanently damaged, and this could result in liver failure and liver cancer.²

Hepatitis

Hepatitis is a condition where the liver is inflamed. There are different types of hepatitis. Hepatitis A, hepatitis B, hepatitis C, hepatitis D, and hepatitis E result from viral infections. On the other hand, alcoholic hepatitis is inflammation caused by extreme alcohol consumption.³

Haemochromatosis

Haemochromatosis is an inherited disease with a faulty gene that causes a gradual build-up of iron levels. This excess iron could lead to cirrhosis or liver cancer.⁴ 

Primary biliary cirrhosis (PBC)

PBC is an autoimmune condition in which the immune system attacks the bile ducts. Its symptoms include aches in joints and bones, extreme fatigue, dry eyes and mouth, and itchy skin.⁵

Regular and moderate exercise reduces the risk of developing certain liver conditions

A sedentary lifestyle is associated with non-alcoholic fatty liver disease (NAFLD). Regular physical activity and exercise have been shown to lower this risk.⁶ 

Regular and moderate exercise could be any type of activity that can increase your heart rate such as dancing, riding a bike, or even brisk walking. It is advisable to practise these activities for two and a half hours, twice per week to promote muscle building and increase strength.^7,8 

Research has shown a significant association between moderate physical activity and a reduced risk of developing NAFLD, irrespective of body weight. A recent study suggested that there is an inverse relationship between physical activity and liver disease. 

Regular exercise was proven to improve liver enzyme functions and reduce the accumulation of fat in the liver.⁹

Liver enzymes contribute to glucose and fat metabolism, hence a rise in functional liver enzymes leads to an increase in the breakdown of liver fat. Another study recommended doing aerobic exercises for 30 minutes, twice per week to reduce liver fat deposition. Exercise also helps to improve insulin resistance and metabolic disorders which are primary comorbidities for NAFLD.¹⁰ 

Exercise stimulates the oxidation of fatty acids in the liver

Frequent, moderate exercise can promote the oxidation of fatty acids in the liver. Oxidation of fat refers to the process of utilising fatty acids to generate energy for liver functions.¹¹ This is because exercising is said to be able to decrease insulin resistance, lower blood pressure, and decrease the concentration of plasma low-density lipoprotein (LDL), which indirectly enhances the oxidation process.¹²

The oxidation of fatty acids is also influenced by adiponectin which is a regulator of fat oxidation. A recent study on obese individuals suggested that exercise increases adiponectin levels in the body which leads to an increase in fat oxidation.¹³

Regular exercise can reverse the effects of early-stage non-alcoholic fatty liver disease

Currently, there are no specific treatments targeting NAFLD. However, regular exercise has been proven to reverse NAFLD in the early stages. There has been growing evidence showing that exercise can be prescribed to NAFLD patients.

Hepatic steatosis only progresses into a much worse state if there is an increase in liver triglyceride content. A body-weight reduction of at least around 10% displayed significant effects in improving liver histology and reducing liver fibrosis. 

The progression of hepatic steatosis to NASH is affected by the activation of pro-inflammatory genes in the liver. Both low-intensity and high-intensity exercise showed a reduction in the expression of these genes. Therefore, weight loss does reverse the effects of early-stage NAFLD as exercise, regardless of its intensity, exercise ameliorates pro-inflammatory and oxidative stress within the liver.¹⁴ 

The liver is not fond of strenuous exercise

Strenuous exercises are vigorous activities that include⁷

• Running
• Swimming
• Sports e.g football and hockey
• Aerobic activities
• Gymnastics

Extremely vigorous physical activities are not favourable for the liver. In a study focusing on the effects of lifting weights in people assigned males at birth on liver functions, it was shown that there were profound increases in liver parameters for at least 7 days i.e aminotransferase (AST), alanine aminotransferase (ALT), creatine kinase (CK), lactate dehydrogenase (LD), and myoglobin. Significantly high increases in these parameters could affect the function of liver enzymes, which in turn leads to mild liver disease.¹⁵

Strenuous exercise worsens symptoms of liver disease

The symptoms of liver disease worsen when affected people indulge in strenuous activities, mainly due to the impairment of skeletal muscle capabilities. Some symptoms include.^16,17

• Decrease in maximal oxygen consumption (VO₂ peak)
• Portal hypertension
• Weakness
• Fatigue
• Low functional capabilities
• Limited mobility
• Lack of response to exercise

What exercise is safest when living with liver disease?

Exercise can help improve liver function. However, strenuous exercise should be avoided. 

The safest activities involve mild and moderate exercise, as well as activities that are enjoyable, fun, and lift your mood. According to the NHS, the recommended exercise duration for adults is at least two and a half hours of moderate physical activity every week. These activities could include:²

• Yoga 
• Pilates
• Carrying a shopping bag 
• Walking
• Stretching
• Climbing the stairs

Conclusion

It is highly essential that you take good care of your liver as it is an organ that performs essential body functions. While mild physical activities help improve liver disease, vigorous exercise could be life-threatening in people with significant liver disease. 

If you think you are experiencing any of the symptoms mentioned above, the best thing to do is to seek the advice of your healthcare provider. It is also advisable to check your liver regularly especially if you have been living a sedentary lifestyle, drinking excessive amounts of alcohol, or even eating high-calorie foods for years.