Association Between Physical Fitness and Metabolic Syndrome in the Elderly

Physical fitness has an important role for our healthy living. The impact of this fitness is reflected both in improvement in quality of life and in improved longevity of life according to various studies. Dr. Hee-Jin Hwang and Dr. Sang-Hwan Kim from the Department of Family Medicine, International St. Mary’s Hospital, conducted a cross-sectional study to determine the relation between the prevalence of metabolic syndrome and physical fitness in the elderly Koreans.

Their sample consisted of 227 subjects – 121 males and 106 females aged >60 years, who came to Yonsei Woori Geriatric Hospital during the period of November 2008 – February 2009 and who signed up for the research with an informed consent. The subjects were assessed using various measurement indices.

Lifestyle measurement was based on a lifestyle questionnaire, which included questions regarding age and gender, current smoking habits, alcohol consumption and self-reported amounts of physical activity. People with chronic liver or kidney disease were excluded from the study.

Body or anthropometric measurements were done using JENIX automatic measuring equipment to check for height and weight, and body mass index (BMI) was calculated. Waist circumference (WC) was also measured.

Blood pressure, both systolic and diastolic was measured using a sphygmomanometer. Blood tests included fasting glucose, total cholesterol, triglyceride levels, High density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C) and C - reactive protein (CRP) levels. Also glycated hemoglobin level (HbA1c) was tested which is elevated in diabetics.

Physical fitness was measured taking 3 parameters into account – muscular strength was checked by assessing the grasping power using a digital dynamometer; Muscular endurance was tested by employing the sit-up test which checked the tone of the abdominal muscles in sitting up from a supine position per 30 seconds; and cardio-pulmonary fitness was assessed using Tecumseh step test in which heart rate was recorded before, during and 1 minute after working on a high stepper at the rate of 24 steps/minute.

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A measure of physical activity was sought through an International Physical Activity Questionnaire (IPAQ) which took into account activities ranging from sedentary to vigorous exercise, work schedule, mode of transport, domestic chores and spending of leisure time.

The research showed that there was no difference in statistics between people having metabolic syndrome and no metabolic syndrome in relation to age, gender, smoking and drinking habits, diastolic BP, total cholesterol, LDL-C levels, CRP, and physical activity. But there were significant differences seen in case of BMI, WC, prevalence of diabetes and hypertension, fasting glucose levels, HbA1c, triglycerides and HDL-C.

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Metabolic syndrome refers to a group of inter-related risk factors which are of metabolic origin and which promote the development of cardiovascular problems. It is mostly associated with type 2 diabetes and obesity. Three or more of the below criteria must be present to have metabolic syndrome:

• Abdominal obesity – WC >102 cm in males and >88 cm in females (For Asians it has been corrected to >90 cm in males and >80 cm in females).
• High fasting glucose – >100 mg/dl fasting or on diabetic medications.
• High blood pressure – >130 mm Hg systolic and >85 mm Hg diastolic BP.
• High triglyceride levels – >150 mg/dl.
• Low HDL-C levels – <40 mg/dl for males and <50 mg/dl for females.

The study showed that ‘increased BMI and waist circumference’ were related to increased grasping power. This could be explained by the fact that more skeletal muscle mass has more grasping power. Also higher triglyceride levels showed lower performance on the sit up test which can be related to central adiposity and insulin resistance. High diastolic BP and high fasting glucose also showed an increased heart rate at rest. This proves the association between the additional aspects of physical fitness like muscle strength and endurance; and risk of developing metabolic syndrome.

There were a few limitations to the study as well. It is a cross-sectional study hence cause-effect relationship could not be established. Self-reported physical activity is usually greater than an objective measurement hence it could have altered the possibility of a relationship between metabolic syndrome and physical activity. There was a selection bias wherein only older people coming to one hospital were chosen thus excluding younger population with metabolic syndrome and the older people who did not go to that particular hospital. Lastly muscle strength is validated in adolescents but not in the elderly, hence it is not an effective measurement for the older age group.

In conclusion, the research aims at promoting practices that not only improve cardio-pulmonary fitness but also enhance muscle endurance in the elderly.

References:

1. http://www.dmsjournal.com/content/7/1/112

Source-Medindia