Kidney disease refers to damage or disease of the kidneys, what is medically called nephropathy. The medical condition is considered a chronic, noncommunicable disease, which can cause serious health problems or death if not controlled effectively. If not treated properly, it usually progresses through three stages: renal insufficiency, renal failure, and uremia. To help make its treatment more effective, regular exercise and a fit and healthy lifestyle are essential to fighting kidney disease. Each are important for providing energy and strength to the body, and securing better mental and physical health.
According to the Centers for Disease Control and Prevention (CDC), the prevalence of kidney disease has been increasing over the past several decades. In 1988–1994, about 14.5% of people 20 years of age or older in the United States had chronic kidney disease. As of 2009, the number of adults in the United States with diagnosed kidney disease was approximately 4.5 million, or 2% of the total number of adults. The overall statistics are worse when taking into account the number of cases that are estimated to be undiagnosed. When both are considered, approximately 16.8% of all U.S. adults (20 years of age or older) have kidney disease, whether they know or it or not, as of the end of 2011. As of 2014 (according to the CDC), it is estimated that more than 20 million adults in the United States have chronic kidney disease.
Specifically, kidney disease is more of a risk among older men and women. Almost 40% of people who are 60 years of age or older have kidney disease. It also occurs more frequently in people with cardiovascular disease, diabetes, and hypertension (high blood pressure), along with those who are overweight or obese (excessively overweight). In the United States, non-Hispanic blacks, Asian or Pacific Islander Americans, and Native Americans are reported by the CDC to have the highest prevalence rates of kidney disease.
Having kidney disease increase the risk for permanent damage to the kidneys and decreases one's chance of living an active lifestyle. Concurrently, it also raises one's risk of premature death. Those with renal failure often require dialysis or a kidney transplant—both produce drastic changes to one's life. However, many of these negatives can be minimized by regularly exercising and maintaining a healthy lifestyle.
Other causes of kidney disease include:
Symptoms of kidney disease may be present but yet go unnoticed for years, only being diagnosed when kidney disease has become quite serious. Some of the symptoms of kidney disease include:
Regular exercise and eating a healthy diet generally lower the risk of getting kidney disease and reduce the severity of it when it is present. Exercising helps to strengthen muscles, increase energy levels, and maintain an active lifestyle. Regular exercise improves heart function, reduces anxiety and depression, decreases blood pressure and improves its regulation, controls glucose levels for people with diabetes, and helps maintain a healthy body weight.
Because kidney disease is difficult to diagnosis in its early stages; it is usually detected with laboratory tests. Even when symptoms are present, lab tests are needed for verification. For the most part, a diagnosis consists of several techniques that together more accurately access the presence of kidney disease. A combination of blood tests, urine tests, imaging scans, biopsies, and various other measures are used to diagnosis kidney disease.
Blood tests are used to help diagnosis kidney disease. The Blood Urea Nitrogen (BUN) test measures the amount of nitrogen in the blood in the form of urea. Urea is a natural waste product produced when the liver metabolizes proteins and later is removed from the blood by the kidneys. An increased BUN concentration is a strong indication that the kidneys are functioning poorly. An abnormal concentration of nitrogen-containing urea in the blood is called azotemia.
Another test measures the level of serum creatinine in the blood. The kidneys normally remove it from the blood. However, when serum creatinine levels are abnormally high, degraded function of the kidneys may exist. Glomerular filtration rate (GFR), a measure of kidney function, can also be estimated from the serum creatinine test.
Electrolyte levels in the blood are also analyzed as part of blood tests. An imbalance of certain electrolytes, such as calcium, phosphorus, and potassium, is a reliable indication that the kidneys are functioning abnormally. For instance, a lower-than-normal amount of the mineral calcium can indicate reduced production of vitamin D; which can lead to weakened bones and degraded kidney function. Further, a higher-than-normal level of the mineral phosphorus can indicate the kidneys are not eliminating it as well as they should. Maintaining a normal phosphorus level is important for preventing high blood pressure and reducing weakened bones. The parathyroid hormone (PTH) test measures the level of PTH in the body, which can mean an incorrect balance of calcium and phosphorus. A high level of potassium, called hyperkalemia, is another sign that kidney disease is likely present. Levels that are too high or low are not good for the heart.
Blood tests are performed when the body is not functioning normally. Several of these tests can indicate the presence of kidney disease. For instance, abnormal levels of testicular or ovarian hormones in men or women, respectively, are two other indicators of reduced kidney function.
In addition, measurements of red blood cell count and hemoglobin are also useful for the testing of kidney disease. Hemoglobin is the part of red blood cells that carries oxygen from the lungs to all parts of the body. When both are lower than normal, then anemia is present, which could mean an iron deficiency. Hematocrit is the measure of the amount of red blood cells that a body is producing. A low hematocrit reading means anemia is present. Further, the transferring saturation (TSAT) and serum ferritin tests are measures of iron in the body, which show the body's ability to grow new red blood cells.
Several tests are used to check for nutritional problems. Serum albumin is a body protein that in lower-than-normal concentrations could mean a person is not getting sufficient protein or calories in the diet. The normalized protein nitrogen appearance (nPNA) test also looks for sufficient amounts of protein. A subjective global assessment (SGA) test is used to see if one is eating a proper diet.
Urinalysis is the process used to analyze urine. It helps to make a proper diagnosis of kidney disease. A “dipstick test” is used to perform the urinalysis. The dipstick contains substances that verify the presence of normal or abnormal constituents of urine. It analyzes blood, leukocytes, nitrite, protein, and other materials. The microalbuminuria test measures the amount of albumin in the urine.
Another urine test involves the analysis of urine creatinine. Creatinine is a side product of muscle deterioration. Further, a protein-to-creatinine ratio test is used to estimate the amount of protein that is excreted in urine every day. The creatinine test also measures the efficiency by which the kidneys are working, what is called the GFR.
Imaging tests are frequently used to diagnosis kidney disease. For instance, ultrasound scans show when the kidneys are smaller than normal, which may point to kidney disease. Such scans are also useful for assessing kidney stones, urinary obstructions, and the amount of blood flow going into the kidneys.
In some cases, a kidney biopsy is performed. A biopsy is a sample of tissue taken from an organ that can be used to analyze the sample to detect abnormalities such as kidney disease.
Other measures are used that help to make a final determination of kidney disease. A measure of body weight is often performed. Unexpectedly losing weight can mean that a person is not getting sufficient nutrients and calories on a daily basis. On the other hand, gaining too much weight can be detrimental to overall health. If weight gain is accompanied by higher blood pressure, shortness of breath, and swelling, then retention of bodily fluids may be occurring—a sign of kidney disease. In addition, blood pressure, total cholesterol, HDL (high-density lipoprotein) and LDL (low-density liporotein) cholesterol, and triglyceride levels are measured to identify possible kidney problems.
Several medications should also be avoided because they can cause problems for the kidneys:
A registered dietitian should decide which of these medications need to be eliminated or reduced, while in consultation with a healthcare professional. It is always recommended to make sure the attending physician knows about all medications being taken, whether they are prescription or over-the-counter drugs or herbal medications.
To treat kidney disease properly, patients should also control their blood pressure, stop using tobacco products, and lose weight if overweight or obese. All of these problems can be controlled by living a healthy lifestyle that includes regular exercise and the consumption of nutritious foods. For instance, the National Kidney Foundation recommends the following exercises for people with kidney disease:
The prognosis for someone with kidney disease is not good. There is no cure. The disease progresses from its early stages until dialysis or a transplant is needed. In addition, people with kidney disease are more prone to have heart attacks and strokes. According to WebMD, people beginning dialysis have a 32% survival rate after five years. Those receiving a kidney transplant from a live donor have a 90% chance of surviving two years, while patients receiving a kidney from a deceased donor have an 88% chance for two-year survival.
Kidney disease for the most part cannot be prevented. However, the risk from the disease can be minimized by controlling diabetes, high blood pressure, and high cholesterol. Exercise can help to reduce this risk. People with kidney disease who are sedentary in their lifestyle will continue to lose strength, mass, and tone in their muscles. With such degradation, it is less likely for these people to move around and maintain an independent lifestyle. Instead, they are more likely to become disabled or bedridden.
The National Kidney Foundation makes the following statement about exercise and kidney disease: “People on dialysis, who exercise regularly, report they sleep better, have more energy and more muscle strength, and are better able to do the things they have to do in their lives. Regular exercise is important for those with newly diagnosed kidney disease, those who are on dialysis, and those who have had a transplant.”
Acierno, Mark J., and Mary Anna Labato, eds. Kidney Diseases and Renal Replacement Therapies. Philadelphia: W. B. Saunders, 2011.
Duyff, Roberta Larson. American Dietetic Association Complete Food and Nutrition Guide, 4th ed. Chicago: American Dietetic Association, 2012.
Mertig, Rita G. What Nurses Know…Diabetes. New York: Demos, 2011.
Narayan, K. M. Venkat, et al., eds. Diabetes Public Health: From Data to Policy. Oxford: Oxford University Press, 2011.
“Assessing Your Weight and Health Risk.” National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/health/educational/lose_wt/risk.htm (accessed January 17, 2017).
“CDC: Kidney Disease Up 16% in U.S.” WebMD. (March 1, 2007). http://www.webmd.com/news/20070301/cdc-kidney-disease-up-16-percent-in-us (accessed January 17, 2017).
“Chronic Kidney Disease.” eMedicineHealth.com . September 15, 2011. http://www.emedicinehealth.com/chronic_kidney_disease-health/article_em.htm (accessed January 17, 2017).
“Kidney Disease.” Centers for Disease Control and Prevention. October 16, 2016. https://www.cdc.gov/nchs/fastats/kidney-disease.htm (accessed January 17, 2017).
Staying Fit with Kidney Disease. National Kidney Foundation. https://www.kidney.org/sites/default/files/11-10-0502_IBD_stayfit.pdf (accessed January 17, 2017).
American Council on Exercise, 4851 Paramount Dr., San Diego, CA, 92123, (858) 576-6500, (888) 825-3636, Fax: (858) 576-6564, support@acefitness. org, http://www.fitness.gov .
American Dietetic Association, 120 S Riverside Plaza, Ste. 2190, Chicago, IL, 60606, (312) 899-0040, (800) 877-1600, http://www.eatright.org .
Centers for Disease Control and Prevention, 1600 Clifton Rd., Atlanta, GA, 30333, (800) 232-4636, cdcinfo@cdc. gov, http://www.cdc.gov .
National Coalition for Promoting Physical Activity, 1150 Connecticut Ave., NW, Ste. 300, Washington, DC, 20036, (202) 454-7521, email@example.com, http://www.ncppa.org .
National Heart, Lung and Blood Institute, PO Box 30105, Bethesda, MD, 20824-0105, (301) 592-8573, nhlbiinfo@ nhlbi.nih.gov, http://www.nhlbi.nih.gov .
The Obesity Society, 1110 Bonifant St., Ste. 500, Silver Spring, MD, 20910, (301) 563-6526, Fax: (301) 563-6595, http://www.obesity.org .
William A. Atkins, BB, BS, MBA