1Titus Terwase Chior
2Florence Doolumun Chior
1Department of Physical and Health Education
College of Education
Katsina-Ala Benue State
2Department of Human Kinetics and Health Education
Benue State University
Makurdi Benue State
The prevalence of the metabolic syndrome (MetSyn) has dramatically increased over the last few decades and has become a major health challenge globally. Metabolic syndrome is a common pathophysiological condition with implications for the development of many chronic diseases. It is a cluster of related metabolic abnormalities and risk factors that considerably increase the development of type 2 diabetes and cardiovascular problems. These include, obesity, hypertension, insulin resistance, glucose intolerance/non-insulin dependent diabetes mellitus (NIDDM) and dyslipidaemia (hypertriglyceridaemia). It was first mentioned in 1966 by Casmus, and largely propagated by Reaven in 1988. The WHO projects that in the next ten years, Africans will experience the largest increase in death rates from cardiovascular, cancer and respiratory diseases and diabetes. This review is an attempt to enlighten the populace on the prevalence and incidence of the MetSyn in this part of the world and what can be done to prevent it, as well as counteract its ugly effects. In this paper, definitions of MetSyn, determinants of MetSyn, causes of the syndrome and lastly, role of regular exercise program in the treatment of the metabolic syndrome are considered.
Keywords: metabolic syndrome, risk factors, insulin resistance.
The prevalence of chronic and non-communicable diseases is escalating much more rapidly in developing countries than in industrialized countries. The WHO estimates that by the year 2020, non-communicable diseases will account for approximately three quarters of all deaths in the developing world. Metabolic syndrome though mentioned around 1988 (Ericksson, Taimela & Koivisto, 1997) is still relatively known in Nigeria. In the western world, a lot of studies have been done on metabolic syndrome in both pediatrics and adult populations (Coquart, Boitel, Borel, Matran, Mounier-Vehier & Gorun, 2014). In the developing world, Kelishadi (2007) reported that the few studies carried out showed a considerably high prevalence of the metabolic syndrome among youths.
In Nigeria, Ibrahim (2012) reported that few studies have been done on several components of the syndrome. In recent times, it has been noted that people are experiencing the occurrence of non-communicable diseases than ever before, as they suffer from high blood pressure, elevated blood glucose and low HDL-c, leading to diabetes and/or cardiovascular diseases. This by implication means that many of these people would have met the criteria for metabolic syndrome if tested, without knowing it.
This review is therefore aimed at helping to bring to lime light the metabolic syndrome. Since most of these problems manifest in latter life (adult and old age), early identification, prevention, and treatment of the metabolic syndrome in young adults using exercises would help to reduce the effects of the metabolic syndrome on the populace, especially the rural and poor populace that are not readily exposed to or do not have access to some of the other (advanced) measures of controlling, or treating it.
Metabolic Syndrome (MetSyn) or Syndrome X or Insulin Resistance Syndrome (among many other names) is a cluster of related metabolic abnormalities and risk factors that considerably increase the development of type 2 diabetes and cardiovascular problems, (Ibrahim, 2012). MetSyn is also considered as a disorder of energy utilization and storage, diagnosed by co-occurrence of three out of five of these medical conditions of abdominal obesity, elevated blood pressure, elevated fasting plasma glucose, high serum triglycerides and low high density cholesterol levels, (Livingstone, Nuriddin, Staggers & Butler, 2013).
Omeiza (2012), stated that one of the first people to introduce the metabolic Syndrome in the scientific literature was Casmus in 1966. However, it did not receive much attention until Reaven introduced Syndrome X in 1988, (Ibrahim, 2012) which was characterized by hypertension, impairment of glucose, and lipid metabolism and insulin resistance. Metabolic Syndrome (Kala & Abhilash, 2013) is a multifaceted syndrome characterized by five major abnormalities; obesity, hypertension, insulin resistance, glucose intolerance/non-insulin dependent diabetes mellitus (NIDDM) and dyslipidaemia (hypertriglyceridaemia). Put in simple terms, MetSyn is characterized by excess fat deposits in the abdomen (abdominal obesity), a condition in which the hormone insulin works less effectively on the body cells, leading to high blood glucose (sugar) level; high fat and lipid levels and low levels of high density lipoprotein cholesterol and raised blood pressure.
Deen (2004) asserted (as cited in Chior, 2014) that when a person has many of these problems at the same time doctors commonly call it metabolic syndrome. Metabolic Syndrome is present if one has three or more of the followings:
- Blood pressure equal to or higher than 130/85mmHg.
- Fasting blood sugar (glucose) equal to or higher than 100mg/dl.
- Large waist circumference (length around the waist) of 40 inches or more for men and 35 inches or more for women.
- Low HDL cholesterol of under 40mg/dl for men and under 50mg/dl for women.
- Triglycerides equal to or higher than 150mg/dl.
This assertion is supported by that presented by Hunter (2013), who also mentioned that metabolic syndrome is present if three or more of these conditions are noted.
Determinants of Metabolic Syndrome
The determinants of metabolic syndrome are high blood pressure, high fasting blood sugar, insulin resistance, abdominal obesity, and high cholesterol, (Kalu & Abhilash, 2013). They noted that while the pathogenesis of the syndrome is complex and not well understood, central obesity and insulin resistance are acknowledged as important causative factors.
High blood pressure
High blood pressure or hypertension as it is popularly known is a major health problem afflicting approximately 15 – 30% of individuals in the western societies (Ericksson, et al. 1997). It is an independent risk factor for atherosclerosis, which is the most common cause of death world wide (Ibrahim, 2012). Elevated systolic and diastolic blood pressure is associated with a higher risk of developing coronary heart diseases when blood pressure (persistently) is equal to or higher than 140/90mmHg.
Regular physical exercise has been recommended for the prevention and treatment of hypertension. The blood pressure-lowering benefits that a given hypertensive individual can expect to derive from participation in exercise programs is dependent on body weight, diastolic blood pressure, and the program itself. Interestingly, the reduction in blood pressure observed with regular aerobic endurance exercise has been proposed to be due to the accumulative effects of single exercise bouts rather than long-term adaptations to exercise. A single bout of aerobic exercise reduces blood pressure for 1 to 3 hours, in a similar magnitude, as elicited by chronic exercise training (Omeiza, 2012). Studies (Ray, 2004; Diretrizes, 2006; Fagard, 2006, as cited in Ibrahim, 2012) have shown that active subjects have a lower risk of becoming hypertensive than do sedentary subjects.
Fasting blood glucose
The blood sugar concentration or blood sugar level is the amount of glucose present in the blood stream of human beings. Normally, the body maintains the blood glucose level at a reference range of between 3.6 – 5.8mmol/l. The human body regulates blood glucose through metabolic processes (homeostasis). Blood sugar levels outside the normal range are termed elevated and called hyperglycemia, while low levels of blood sugar are called hypoglycemia, (Ibrahim, 2012). Elevated blood glucose levels in the human body causes type 2 diabetes.
Exercise is considered a cornerstone in the treatment regimen for individuals with manifest NIDDM, and aerobic endurance exercise has traditionally been advocated as the most suitable exercise mode. The recommendations that exercise training can be used as a therapeutic means to lower glucose levels in NIDDM subjects stems primarily from the fact that exercise has pronounced effects upon the metabolism of glucose. Ada (2012) classified the effects of exercise on glucose control in two ways; acute effects and chronic effects. According to her, the acute effects are directly related to the increased rate of muscle glucose restoration, (how much a muscle feeds itself from glucose in the bloodstream) called muscle glycogen repletion. While chronic effects are related to the increase in metabolically active muscle. As regular exercise produces more active muscles, these muscles utilize more glucose thereby keeping the blood level control.
Insulin resistance is a term used to describe an impaired biological response to insulin (Hunter & Garvey (2008) as cited by Livingstone et al., 2013). Insulin resistance present in approximately 25% of the western population plays a central role in the metabolic syndrome being associated with most of the metabolic abnormalities (Ericksson et al. (1997) as cited in Chior, 2014). This is a condition in which the body produces insulin but does not use it effectively. When this happens, an individual’s glucose builds up in the blood instead of being absorbed by the cells, leading to type 2 diabetes or prediabetes
Like elevated glucose levels, insulin resistance can be regulated through regular exercise. The effects both acute and chronic exercises have on insulin sensitivity have been assessed (Kala & Abhilash, 2013). A single bout of acute exercise enhances insulin-mediated glucose disposal in normal subjects, in insulin-resistant first degree relatives of NIDDM subjects, in obese subjects with insulin resistance as well as in NIDDM subjects. They however maintained that because the increase in insulin sensitivity after acute bout of exercise is short-lived, chronic bouts of exercises should be stressed for better results.
Body Mass Index (BMI; in kg/m2)is widely used for the classification of overweight (BMI25) and obesity (BMI) ≥30) in men and women respectively. BMI correlates reasonably with laboratory-based measures of adiposity for population studies and extremely practiced in most clinical settings according to Zhu et al, (2002) as cited in Ibrahim, 2012.
Regular exercise has been recommended for the prevention and treatment of abdominal obesity just like the other components of the MetSyn.
Dyslipidaemia associated with the metabolic syndrome is primarily characterized by hypertriglyceridaemia and low levels of HDL-cholesterol. The effects of exercise on lipid and lipoprotein profiles are fairly well known (Ericksson, et al. 1997). However, in a recent study (Ada, 2012), it was documented that physical training is associated with a lowering of serum triglyceride concentrations, particularly very- low-density lipoproteins (VLDL2) cholesterol with training.
Factors influencing the development of metabolic syndrome
The following factors among others have been considered as increasing the chances of developing metabolic syndrome according to Kelishadi, et al. (in press):
- Age. The prevalence of MetSyn increases with age, affecting less than 10 percent of people in their 20s and 40 percent of people in their 60s. Adults who continue to gain 5 or more pounds per year raise their risk of developing metabolic syndrome by up to 45%.
- Race. Hispanias and Asians seem to be more at risk for MetSyn than other races are.
- Progressive weight gain. Metabolic syndrome is present in about 5% of people with normal body weight, 22% of those who are overweight and 60% of those considered obese.
- Obesity. A body mass index (BMI) – a measure of ones percentage body fat based on height and weight – greater than 25 increases the risk of MetSyn. So does abdominal obesity – having an apple shape rather than a pear shape.
- History of diabetes. An individual is more likely to have metabolic syndrome if he/she has a family history of type 2 diabetes or a history of diabetes during pregnancy (gestational diabetes).
- Other diseases. A diagnosis of high blood pressure, cardiovascular disease or polycystic ovary syndrome – a similar type of metabolic problem that affects a woman’s hormones and reproductive system – also increases the risk of MetSyn.
- Low physical activity. A sustainable exercise program, for example, 30 minutes, 5 days a week is reasonable to start, providing there is no medical contraindication.
- Diet. A diet that is rich in “good” fats (Olive oil) and contains a reasonable amount of carbohydrates and proteins (such as from fish and chicken).
- Lifestyle. Sedentary work, smoking, eating an excessively high carbohydrate diet, and consuming an alcohol – free diet.
The Role of Exercise in The Management of Metabolic Syndrome
Metabolic syndrome needs to be managed in order to reduce the long term risk of type 2 diabetes and cardiovascular disease. Fortunately, the syndrome can usually be reversed with lifestyle changes. The combination of weight loss and exercise produces the best effect. Exercise is any bodily activity that enhances or maintains physical fitness and overall health and wellness. It is performed for various reasons, including strengthening muscles and the cardiovascular system, weight loss or maintenance and merely enjoyment. Frequent exercises boost the immune system and help prevent heart diseases, cardiovascular diseases, type 2 diabetes and obesity.
A combination of frequency, intensity, and duration of chronic exercise is responsible for producing a training effect, (ACSM, 1990). People with MetSyn can exercise safely if the exercise program begins slowly and progresses appropriately. The general recommendation for adults to participate in aerobic exercise on most days of the week holds for people with MetSyn; because improvements in insulin action are usually lost within 24-28 hours of exercising, (Johnson, et al., 2007). Aerobic exercises that use the large muscle groups (e.g. brisk walking, jogging, cycling, swimming, dancing, playing ball games and other sporting activities) are appropriate and effective. To be effective it is better to aim for a minimum of 2.5 hours each week; however for weight loss, or to prevent regaining weight, exercise should be for 4 hours or more each week. Aerobic exercise can reduce waist measurement by 2-5cm, (Kay & Fiatarone, 2006) even without weight loss. For overweight or obese people, the recommended level of exercise can significantly lower systolic and diastolic blood pressure, (by approximately 5.5mm Hg each); improve control of blood glucose levels; lower blood lipids (by 0.2-0.3mmol/L, up to 1.39mmol/L; and increase HDL-c (by 0.02-0.13mmol/L, up to 0.20mmol/L.
While resistance exercises (e.g. weights training) can also benefit people with MetSyn, they may not reduce abdominal fat. However, a combination of aerobic exercise and progressive resistance training reduces the risk of progressing to type 2 diabetes. It is therefore recommended to use resistance exercise to complement, but not to replace aerobic exercise training. Johnson, et al. (2007) maintained that moderate intensity aerobic exercise is best for overall improvement in the metabolic syndrome, and is more likely to be sustained than a program of vigorous exercise. A simple rule of thumb is to exercise at a level that increases your breathing and heart rate but still allows you to maintain a conversation. According to them, do 5-10 minutes of warm-up exercises (light aerobic activities) before your exercise sessions. A resistance exercise program performed at least twice a week can improve insulin action, good cholesterol and blood pressure.
Hunter (2012) recommended the use of high intensity interval training (HIIT) for people with metabolic syndrome. It is characterized by alternating periods of short, high intensity, anaerobic exercise with lower intensity, recovery periods. The HIIT has the following advantages over other exercise programs;
- HIIT workout takes only 9-20 minutes
- It decreases cortisol, (stress hormone) reducing inflammation and allowing the body to burn fat more efficiently.
- HIIT results in increased growth hormone and testosterone which supercharges the body’s fat burning and muscle building.
- HIIT reduces inflammation and resulting pain. Above all. HIIT results to an after-burn effect, as one burns energy rapidly and continues to burn fat 36 hours after completion of exercise.
This review of the prevalence of metabolic syndrome has revealed alarming rates of the syndrome in both industrialized and developing nations of the world. The desire to prevent the development of the syndrome later in life should be the concern of all, such that exercise programs can be designed to help curtail the development of the syndrome in early childhood. This article has exposed the existence of MetSyn in this part of the world. It is intended that it will help to prevent the sudden death syndrome that has become commonplace among our youths and adults, and further promote the physical activity culture among our people.
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