What is kidney disease?

Kidney disease is a medical condition that negatively affects the filtering function (of blood) of the kidneys. The term kidney disease is relatively broad, including conditions like kidney stones as well as more severe and potentially fatal conditions such as chronic kidney disease and cancer. According to the latest research, approximately 800 million individuals have chronic kidney disease globally.¹

Symptoms of kidney disease

As the term ‘kidney disease’ is relatively broad, the symptoms can vary greatly depending on which type of disease is present. Below are some of the symptoms of kidney disease¹:

·         Weight loss

·         Loss of appetite

·         Blood in your urine

·         Swollen ankles, feet and hands

·         Breathlessness

·         Fatigue

·         Nausea/vomiting

·         Sleeping difficulties

·         Itchy skin

·         Headaches

·         Cramps

Causes of kidney disease

The development of kidney disease can be attributed to a wide range of factors, with certain factors carrying a higher risk compared to others. Below are some of the most common causes of kidney disease.

• Diabetes - Studies have identified diabetes as one of the most prominent causes of kidney disease.² As diabetics are unable to naturally control their blood glucose levels, the tiny filters on our kidneys can become damaged due to overexposure to glucose.
• Hypertension - High blood pressure is also another cause of kidney disease.³ High blood pressure can cause the blood vessels within our kidneys to become strained and damaged, preventing the kidneys from functioning properly.
• High blood cholesterol levels - High levels of blood cholesterol can cause the blood vessels that supply the kidneys with oxygen and nutrients to become narrowed or blocked, leaving the kidneys ill-nourished and eventually damaged.³
• Kidney inflammation - Glomerulonephritis (inflammation of the filters in the kidneys) can cause internal kidney damage over a prolonged period of time, limiting their ability to properly filter blood.
• Kidney infections/conditions - Severe kidney infections can cause both temporary and permanent kidney damage, preventing them from functioning properly.
• Certain medications - If taken for a prolonged period of time, certain medications have been linked to an increased risk of kidney disease. Below are some of the medications that can increase our risk of kidney disease¹ :

• Lithium (treatment of mood disorders)
• Aspirin
• Ibuprofen
• Naproxen
• Diclofenac

Benefits of being active with kidney disease

Leading an active lifestyle can be extremely beneficial for those with kidney disease. As well as improving overall health, exercise has been shown to provide many kidney-specific benefits. Below is a list of some of the key benefits exercise can provide for those living with kidney disease.

Lower blood pressure

Due to the important role our kidneys play in regulating blood pressure, kidney disease patients are more susceptible to renal hypertension (high blood pressure caused by kidney damage). Unfortunately, this leaves kidney disease patients prone to further kidney damage as well as cardiovascular-related issues such as heart attacks, coronary heart disease and stroke. 

Whilst further research is currently required within the field, studies have found that exercise has the potential to control blood pressure levels in those with kidney disease, reducing the risk of renal hypertension.⁴

Keeps blood sugar levels in check

When damaged, our kidneys lose some or all of their functionality, potentially limiting their ability to properly remove insulin (the hormone responsible for breaking down glucose) from our bloodstream. Whilst insulin plays a key role in energy production and preventing spikes in blood sugar levels, excessive insulin levels can be dangerous and cause a drastic decrease in blood sugar levels.

This is where exercise can help those diagnosed with kidney disease. Research has found that exercise can help improve kidney function, even in those with more severe forms of kidney disease.⁵

Maintaining a stable body weight

Both weight gain and loss are common in kidney disease patients, making it difficult for them to maintain a stable body weight. The effect of kidney disease on a patient's weight can differ depending on the severity of the condition.Common kidney disease symptoms such as loss of appetite can cause a patient to lose weight, whereas, the kidney's impaired ability to filter out fluids can result in gaining ‘water weight’.⁵

Exercise can support an individual in both weight gain and weight loss. For patients trying to reduce their body mass index (BMI), low-intensity exercise burns fat as its primary fuel source, therefore aiding in weight loss. Regular exercise also significantly improves appetite and helps build muscle mass, therefore allowing an individual to maintain a healthy weight.

What kind of exercise is best for kidney disease?

Knowing which exercises are safe is vital for kidney disease patients. Performing the wrong exercises or overexerting in the gym can cause further kidney damage. It is advised to make sure you speak to your doctor before commencing any exercise routines. Below are the safest and most beneficial ways for kidney disease patients to work out.

Aerobic exercise

According to the National Kidney Foundation, continuous aerobic exercise performed at a low to moderate intensity is the safest and most beneficial form of physical activity for kidney disease patients. Aerobic exercises are considered the safest form of exercise. 

Unlike high-intensity weight training, aerobic exercises do not cause a sudden and sharp rise in blood pressure and thus do not risk further kidney damage. It is recommended that an individual performs roughly 150 minutes of aerobic exercise per week.⁴ Examples of aerobic exercise include:

• Walking
• Jogging
• Cycling
• Swimming

Resistance exercise

Resistance-based exercises can also be beneficial for kidney disease patients if performed correctly. Whilst high-intensity resistance training may cause further kidney damage, low-intensity resistance training can provide benefits to kidney disease patients. To perform low-intensity resistance training, perform a high number of repetitions with low weight. For example, performing 30 repetitions with a 3kg weight rather than 5 repetitions with a 15kg weight.⁴

Conclusion

The correct form of exercise can be extremely beneficial for kidney disease patients.  Numerous studies have found that regular aerobic exercise can help kidney patients manage their condition, lead a higher quality of life and maintain their overall health. If you have been diagnosed with kidney disease and are thinking about taking up exercise, ensure to speak with your healthcare provider before to ensure it is safe to do so.