Effects of Sedentary Lifestyle on Obesity

Introduction

Currently, obesity and overweight is a main global health problem plaguing almost the whole planet. Studies show that in 2005 1.6 billion adults were overweight and 400 million adults were obese. As it is portrayed, obesity and overweight is a problem of the contemporary societies that cannot be confronted. According to a recent study of the World Health Organisation, it is predicted that there will be 2.3 billion overweight adults by 2015 in the world and more than 700 million of them will be obese. Also it is important to realise that obesity and overweigh are modern problems of the societies since statistics referring to these problems did not exist 60 years ago. Therefore, it is clear that obesity and overweight apart from genetic predisposition and psychological disorders might derive as well from the modern sedentary lifestyle that is highly affected by the recent technological development and from poor nutrition as there is an increase in convenience food. However in order to understand the extent and significance of the problem it is important to define and analyse overweight and obesity.

Obesity can be defined as a medical condition in which body fat has accumulated to the extent that it has a negative effect on health. A healthy body requires a minimum amount of fat for the proper functioning of the hormonal, reproductive, and immune systems, as thermal insulation, as shock absorption for sensitive areas, and as energy for future use. But the accumulation of too much storage fat can impair movement and flexibility, can alter the appearance of the body and cause health problems.

Obesity increases the likelihood of various diseases like heart disease, type 2 diabetes, breathing difficulties during sleep (pulmonary diseases), hypertension, certain types of cancer, and osteoarthritis. In particular, cancer of the colon as well as prostate in men and cancer in breasts, ovaries and cervix in women have been found to be related to obesity. Furthermore, hypertension has been found to be related CHD and strokes. As a result, obesity has been found to reduce life expectancy and be one of the leading preventable causes of death worldwide. Investigators have estimated that if everybody had the optimal body mass there would be 3 years added to life expectancy, 25 percent less coronary heart disease and 35 percent less congestive heart failure and brain infection.

Overweight is generally defined as having more body fat than is optimally healthy, without reaching the body fat value for obesity. The generally accepted view is that being overweight causes similar health problems to obesity, but to a minor degree. It is estimated that the risk of death increases by 20 to 40 percent among overweight people and that being overweight at age 40 reduces life expectancy by three years.

Being overweight or obese has been identified also as a cause of cancer. Psychological well-being is also at risk in the overweight individual due to social discrimination. However, children under the age of eight are normally not affected.

The prevalence of obesity and overweight is strongly related to age. The 16 to 24 years age group (for both men and women) is substantially less at risk of becoming obese than older age groups. Those aged between 25 and 34 have the second lowest rates of obesity and overweight. Middle aged people are those who are in the most risky position of becoming obese or overweight.

In order to further understand obesity and overweight it is important to analyse the methods used in order to classify and tell the degree to which a person is overweight or obese. The most popular method used is that of the Body Mass index (BMI), or Quetelet index. The Body Mass index is a statistical measure of body weight based on a person’s weight and height. Though it does not actually measure the percentage of body fat, it is used to estimate a healthy body weight based on a person’s height. Due to its ease of measurement and calculation, it is the most popular diagnostic tool to identify weight problems within a population, usually to classify adult underweight, overweight and obesity.

Body Mass Index is found by dividing the body mass in kilograms by the square of height in meters.

This technique can also act as a health since it appears to provide relative results concerning the degree of risk associated with overweight or obesity.

Mortality and morbidity start increase at high rates at a BMI of more than 25. Therefore the desired levels of BMI are those below 25. Below there is a table of the BMI classification according to the World Health Organisation confirming what was previously stated.

Classification

BMI(kg/m2)

Underweight

<18.50

Severe thinness

<16.00

Moderate thinness

16.00 – 16.99

Mild thinness

17.00 – 18.49

Normal range

18.50 – 24.99

Overweight

?25.00

Pre-obese

25.00 – 29.99

Obese

?30.00

Obese class I

30.00 – 34.99

Obese class II

35.00 – 39.99

Obese class III

?40.00

As stated at the beginning there is not a single factor that can be considered responsible for obesity and overweight. One of these factors stated is sedentary lifestyle. Sedentary lifestyle is a medical term used to describe a type of lifestyle with no or irregular physical activity. It is commonly found in both the developed and developing world. Sedentary life is mainly influenced by the technological development and innovation which simplifies all daily tasks people were used to do. Inactivity of the modern world restricts even simple activity at all levels and prevents energy consumption which lead to fat accumulation and therefore an increase in the body mass. Sedentary activities include sitting, reading, watching television and computer use for much of the day with little or no vigorous physical exercise. It is well-known that modern societies are characterised by this inactivity which derives from the modern sitting life. This is the lifestyle including the seat of the car, the chair of the desk in the office and the sofa and bed at home. Watching TV or using the computer is a main part of somebody’s life especially in the western countries. A sedentary lifestyle can be responsible for many preventable causes of death, like overweight and obesity.

Aim

The aim of this study is to denote the effects of sedentary lifestyle on overweight and obesity. This will be achieved by collecting data showing the inactivity of people caused by the contemporary sedentary lifestyle and by relating this data to their Body Mass Index to see whether or not it is affected by their lifestyle. It hypothesised that participants with sedentary lifestyle will have greater BMI values than the participants with a more active lifestyle. It is important to state that this study examines only sedentary life as a factor contributing to overweight and obesity. This means that only this cause of overweight and obesity will be isolated in order to deliver more accurate results concerning the effect of sedentary life on BMI. Therefore, diet, psychological cause and genetic predisposition will be ignores in this study.

Materials and Methods

A questionnaire was given to a random sample of 5 men and 5 women with criteria being age, nationality and social status. The same social status was chosen since education can influence lifestyle; therefore different social statuses would have acted as a confounding variable to the study. The individuals were between the ages of 20 and 30 for both men and women. Same age range was chosen since all the above information stated concerning overweight and obesity was referring to adults. Also, as mentioned in the introduction, overweight and obesity has different consequences on minors or elderly people since prevalence rate can vary. Moreover metabolic rate is age dependent, so choosing participants from the same age group would help isolate this factor. In addition, nationality and social status may be factors determining lifestyle, so individuals of Greek nationality with a minimum of education (high school education at least) and a permanent job were chosen to be participants in the study. Also all participants were chosen to be drivers in order to investigate whether or not they use their car appropriately in order to combine its usage with some physical exercise when possible.

All participants answered the following questionnaire:

Questionnaire

What is your age (years)?

State you height (in meters)

State your body mass (in kilograms)

For the questions in which you are asked to answer in hours, answer 0 if you do not execute the activity described or if answer is less than 30 min. You have to round answer in approximate integer number of hours or half hours if needed (i.e. 1, 2, 2.5 and 0.5).

How many hours approximately do you watch TV per day?

How many hours approximately do you sit in front of you computer monitor (or staying in a fixed position with your laptop)?

How many hours approximately do you spend talking on the fixed-line telephone?

How many hours approximately do you spend playing with game consoles (please exclude physical activity games like virtual gym training, etc)?

Do you use any other electronic device that contributes to physical inactivity? Describe briefly (state hours of usage per day).

How many hours approximately do you spend physically exercising (gym, jogging, sports, etc)?

The Body Mass Index (BMI) was calculated by using the following formula:

The total hours of inactivity were calculated for all persons. This was achieved by adding all the numbers of hours from the questions 4 to 8 which talked about sedentary activities. Then hours answered in question 9 were subtracted by the sum.

Participants were named with a number from 1 to 10 with 1 to 5 being male and 6 to 10 being female. Participants were then divided into two categories according to their approximate daily hours of inactivity as these were calculated from the questionnaire.

Results
Participant number
Approximate Daily Hours of Inactivity
BMI
1
7
24.7
2
3.5
21.5
3
17.5
29.6
4
9
27.4
5
6.5
24.3
6
10.5
28.1
7
9
25.5
8
8
24.7
9
2
22.3
10
4.5
23.1

Table 1

Results were then arranged by ascending Approximate Daily Hours of Inactivity in table 2.

Participant number
Approximate Daily Hours of Inactivity
BMI
9
2
22.3
2
3.5
21.5
10
4.5
23.1
5
6.5
24.3
1
7
24.7
8
8
24.7
4
9
27.4
7
9
25.5
6
10.5
28.1
3
17.5
29.6

Table 2

Below we can see how ascending inactivity hours relate to the BMI values.

In the above graph we can see that BMI values follow a trend and they are almost proportionate to the hours of inactivity with some exceptions. The exceptions are the BMI values that correspond to 2 and 9 inactivity hours. These BMI values do not seem to follow the general trend and distance from the trend line.

In tables 1 and 2, the Approximate Inactivity Hours and BMI (Body Mass Index) of participants are shown. The BMI is very useful in order to be able to compare the participants with regard to their Approximate Hours of Inactivity, as body mass itself (in kilograms) does not measure the body frame and cannot indicate the existence of fatness except in extreme cases. The only occasion in which we would be able to use body mass (in kilograms) for the comparison, would be if we included height in our calculations. The BMI can also be used as a health index, as previously stated hypertension and cardiovascular diseases can be predicted as we reach the obesity threshold.

Through these tables it is observable that the use of technological facilities and generally the inactivity that sedentary lifestyle involves, leads to a decrease of a health status of both men and women. It is certain that in a global level, the outcome of this health decline because of inactivity will have unpredictable consequences in health industry and life span expectancy. It is clear that the general trend in the chart shows that as inactivity hours increase, BMI increases as well. The samples of the study derive from young participants. So, it is clear and straightforward that as these people grow older, the effect of inactivity will become worse and so the participants with high BMI will gain more kilograms and the result will be that their BMI will increase along with their fat accumulation in their body which will result to the prevalence of health problems.

Discussion

By observing the set of data shown in the results, it can be easily concluded that people utilising modern appliances in their everyday life and people with a sedentary lifestyle are have more accumulated fat since their BMI values are higher. It would be of utmost importance to examine these people several years later in order to be able to compare the present results with the future ones and analyse any differences that would possibly have emerged. Of course an alternative way of comparison could be to compare past sets of data of the specific participants. However, this was not possible because only a small number of participants could recall their body mass and height figures 5 years ago. Furthermore, no one could state the exact period of time during which their sedentary activity took place. So a correlation between the exact hours of inactivity and the BMI’s was not feasible.

As mentioned previously the BMI can be also used as a health index since from clinical studies it becomes clear that there is some correlation between the BMI and mortality. Also, the BMI of people being sedentary and utilising technology devices in their everyday life is an overweight range and has increased risks for developing some kind of disease, while the BMI of the people not having a sedentary lifestyle is in the normal range and definitely has fewer chances to develop morbidity. A point of major concern is that year after year, the non-sedentary category will start to dissapear, as all new products, due to industry competition, will have the same characteristics and some commodities will become extinct. This implies that even if people do not want to use some kind of technology they will not have an option, as there will be no alternatives in the market because some traditional products will have become extinct.

This study takes under consideration the hours spent in front of a TV set or a computer monitor. These are the most popular modern activities that are said to contribute to a 45% to overweight and obesity. In addition, there is a great variation in the amount of time spent for TV watching among people. But except of the inactivity that TV watching produces, there are other modern habits like consumption of snacks, soft drinks, beer and generally alcohol drinks which contribute to the increase of body mass as well, or deteriorate conditions such as blood pressure and liver functioning directly. These factors influencing BMI were not taken under consideration in this study. In addition it is significant to say that today the time spent on the computer has started being an important part of everyday life. The number of Internet users increases by leaps and bounds and so does the time spent in front of the monitor navigating in the net. However, sixty years ago, these activities were not part of everyday life and people had different types of leisure activities that were not sedentary and which possibly involved more muscular exercise. Moreover, in the past most professions required physical activity so there was more energy consumption, less fat accumulation and well-being. One of the disadvantages of having TV sets and computers at home, is that young children become to consider them as a normal and natural way of daily activity, and together with the fact that in big developed cities due to space restriction from buildings and roads, playgrounds and outdoor activities are starting to extinct, the problem of overweight and obesity starts to appear early on children’s life. Evidence for this comes from the fact that childhood obesity has increased lately in all developed countries and TV and reduced outdoor activities have been the cause of this inactivity.

The problem of inactivity does not contribute only to body mass gain but also to development of various diseases or degenerative states, basically with the skeleto-muscular system. Lower back problems and joint problems have become very popular in a wide range of ages. These diseases develop from the relative inactivity and they are aggravated from the increased body weight. If we take into consideration some other factors that affect health, such as type of food consumed, the expansion of fast-food habits, the consumption of alcohol, pollution, cigarette smoking and the stress of everyday life, we can easily understand that health predictions cannot be very hopeful.

Furthermore, there are other factors that contribute to this body mass gain as well. One very important factor is nutrition or diet. Contemporary nutrition is not as healthy as it was in older times. Fast-food industry has become a convenient and inexpensive way for having a meal and everyday there are more people having fast-food for lunch break as an easy solution especially during weekdays. Fast food is rich in fat and contributes to body mass gain as well. Also, today, people are often tired and exhausted from their work and resort to the services of fast food delivery in order to satisfy their appetite without tiring themselves out more.

Although the sample used in this study is small the results show definitely a general trend. It is worth mentioning that this study investigated only the approximate inactivity hours from some basic everyday sedentary activities. It is obvious that the real daily inactivity hours of each participant are much higher, however in this study only basic activities are included. And since simple sedentary activities like elevator or escalator usage, or sitting in a chair for some seconds only consume a little period of time everyday they were ignored. Therefore as these activities were ignored for all participants results can be considered accurate. Also other activities that require physical exercise during the day were ignored (like walking) but for the above reasons, they were ignored. Also, if other technological devices, such as electric can openers, electric knives etc, were taken into account, the number of activity minutes would increase as well.

As survey figures show overweight and obesity has become a serious problem worldwide. In order to improve this study more aspects of the problem should have been examined. For example, the habits associated with the relative inactivity, or the age at which inactivity starts could have been studied. However, more time and much better sample, both in terms of numbers and socioeconomic status of participants is required for this kind of study, in order to generalise the findings.

Conclusion

In conclusion, the results of this particular study show that sedentary life can actually contribute to overweight and obesity, since BMI is affected almost proportionally by the hours of inactivity. The calculations show that there is a small but substantial relation of the BMI to the approximate hours of inactivity roughly calculated. The progress of technology indicates that the sedentary lifestyle deriving from technological innovations will continue spreading throughout the globe especially in the western cultures. It is expected that this inactivity caused by sedentary life if not confronted with physical exercise will result to higher BMI’s and therefore overweight and obese people. So, if the escalation of overweight and obesity does not cease, most people living in modern western societies will experience serious illnesses and fatal diseases triggered by overweight and obesity.