18 ENERGY COST OF SELECTED HOUSEHOLD ACTIVITIES

Sarasvathi. V

Energy refers to the ability to do work. All activities of personal well-being and of the home’s efficiency require energy to be carried out. Whether it is standing, sitting or dusting, cooking, repairing- all need energy. It is of prime importance that one, is not, only aware of all energy resource available, but also learns to use them wisely to achieve the family goals. The maxim should be – use of minimum energy for maximum benefit. It is wiser to let a man push, pull and lift heavy articles in the home rather than a woman (who will be using more energy and time to do a similar job).

Energy is required to do work. Energy for work is available from non-human and human sources. Human energy or energy from human sources refer to the individual’s ability to do work. The amount of human energy available for work varies from person to person, as it is department upon the physical and mental state of a person and also related to heredity and family background of the individual understanding the work.

In order to run a house efficiently, it is imperative that the home-maker be clear about the quantity and quality of energy of energy needed for the varies tasks; she must be clear about how she can acquire sufficient amount by help from other members and through other mechanical devices and above all through efficient planning. She must be clear about her priorities, and plan accordingly.

Energy Requirement

Energy is a basic requirement of man for the maintenance of life growth and physical output. Like other animals, human beings obtain their energy from food in which it exists in chemically bound forms in the molecules of carbohydrates, proteins and fats. This energy from food is liberated through the dynamic bio-chemical oxidative reactions in the body and is utilized in the following functions:

• Maintenance of basal metabolic processes; Promoting growth;
• Regulation of body temperature; and
• Performance of various physical activities.

The amount of energy available to different categories of people varies widely. It is dependent primarily on the physical, mental and economic status of the person.

As for time, we know that during fixed hours of the day with us, we can plan our work accordingly. But in case of energy, it is not easy to measure the energy requirement which is directly related to the energy output or expenditure. It also varies greatly from person to person and is largely influenced by the age, sex, body weight and health of the person.

Fatigue or tiredness from physical work lower one’s capacity to perform subsequent work. This is related to the way a homemaker utilizes her energy as well as her mental approach to meet her home-making responsibilities. So, in order to manage energy effectively a careful planning and thought are required. She can plan her activities in such a way which avoids meaningless wastage of energy so as to utilize the same more effectively in useful activities.

To achieve the economic utilization of the energy, the homemaker needs to understand the followings:

The relation of energy to the stages in the family life cycle;

The energy cost of the various household and occupational activities; The most fatiguing physical activities; and

The form and effects of fatigue.

1.  The relation of energy to the stages in the family life cycle:

Energy demands are different at different stages of life cycle. Sometimes, the workload is too much on the housewife and further there are periods when she is relatively free. Therefore, the relation of energy expenditure to different phases of life cycle is briefed as follow:

Stage I. During this phase just after marriage, only two persons constitute a family and hence energy demands are low. If the home-maker is working outside then energy demands are somewhat higher and she needs to balance her work between her outside work and her work at home.

Stage II. When children are young, energy demands are quite high. All the home activities take more time due to additional load of rearing up children resulting in rapid increase in energy demands.

Stage III and IV. In these stages the work is very high as the children are in nursery, primary and high schools. While meeting the additional requirements such children, the energy demands, both inside and outside the home are increased. This is the phase demanding greatest activity for both the children as well as the family.

Stage V. when children reach college age, they become responsible resulting in lightening the workload on home-maker. Her individual responsibilities are reduced further when children are married off and independently settled. This saves sufficient energy for the home-maker to carry work outside the home.

Stage VI. At this stage the energy demand diminishes and she save energy as at old age she becomes relatively unable to do much work.

2.  The energy cost of the various household and occupational activities.

The amount of energy required to perform a task are measured in terms of ‘oxygen consumed by the body per minute’ for the purpose of oxidation of food for release of energy. The energy value of foods and the energy exchanges in the body are expressed in terms of ‘calories’. Each calorie is the amount of heat required to raise the temperature of one gram of water through 1˚C. the large calorie, i.e., ‘calorie’ also termed as kilocalorie (kcal) is equivalent to 1,000 calories. The energy requirement to perform any task is termed as its ‘energy cost’. Whatever the type of job is, it requires several types of efforts, for example:

v  Mental effort. It is required for doing any task even the routine types, e.g., cooking, cleaning, dressing and washing utensils and clothes. Though these tasks are performed daily, still one has to think about the way to perform the same. Examples: Thinking, Reasoning, Planning, Decision making, Directing, Worrying, Talking.

v  Visual effort. All the activities involve visual efforts, although we are not aware of them. Muscular movement of eyes and adjustment of vision to the objects at different distances and lighting conditions continuously take place while performing any work. Accordingly, our eyes need to direct the movement of our hands, feet and other body parts. Examples: Eye movements, looking, Searching, watching, adjustment to distances and lighting conditions.

v  Manual efforts. This effort is required for the entire household and outside the home tasks, e.g., cooking, mopping, dusting, washing, ironing, pulling and carrying things and attending the office. Examples; Reaching, Raising, Lifting, Holding, Carrying, Stretching, Pulling and pushing.

v  Torsal efforts. These involve movement of the torso and hence are termed torsal efforts. These include bending, leaning, rising, turning, stopping, sitting and knitting. These are needed in doing more strenuous tasks. Examples: Bending, Leaning, Rising, Turning, Stooping,Sitting, and kneeling.

v  Pedal efforts. Some activities in the house involve using one’s legs, which include pedal efforts, e.g., standing, walking, climbing stairs and moving. These are very necessary for home-making and recreational activities. Since whole body needs to be moved around, these activities have heavy energy demands. Examples: Moving, Standing.

From above it becomes clear that the household activities require a combination of more than one type of efforts. In order to have a well-balanced energy spend patterns, home-maker need to know the energy costs of various activities and also those which are most tiring.

Performing each homemaking task requires several types and combinations of effort. For instance, even performing any such routine tasks as dressing, sweeping, or dishwashing, which most homemakers do almost automatically, requires some mental effort. Although we are seldom conscious of it, most activities require visual effort because our eyes must direct the movements of our bodies. Muscular movement of the eyes and adjustment of vision to different distances and lighting conditions take place constantly. Such tasks as preparing meals, setting and clearing the table, dish-washing, and laundering require no small amount of manual effort —reaching, raising, lifting, holding, carrying, pulling, and pushing. Some of the more strenuous tasks, such as those connected with caring for the house, garden, and yard require torsal effort; that is, bending, leaning, rising, turning, stooping, sitting, and kneeling. And pedal effort—walking, moving, and standing—is an essential part of many homemaking and recreational activities.

Thus, while the various homemaking activities require different combinations of effort, most tasks require mental, visual, manual, and torsal effort of some kind, and many also require pedal effort.

Energy Costs of Household Tasks

To work out well-balanced energy-spending patterns, home makers need to know both the energy costs of various home rnaking activities and those considered most fatiguing.

The human energy required for the performance of any task is made up of several different parts. A certain amount of energy is needed for the maintenance of muscular tension and for the natural body processes such as respiration, circulation, secretion, and excretion. This is known as resting metabolism. In addition there is the energy used in moving about and in the actual doing of the task.

Energy costs of a number of household tasks, the tasks were roughly divided into three classes:

(1)   Light work, such as knitting, darning, sewing by hand and with a motor-driven machine;

(2)    Moderate work, such as ironing towels, dressing infants, washing dishes, and sewing with a foot-driven machine; and

(3)   Strenuous work, such as washing towels and sweeping the floor.

Light work requires about 15 percent more energy than resting in a chair that moderate work requires about 24 additional calories per hour, and that strenuous work required about 50 additional calories per hour. Washing dishes at a table 25.6 inches high requires more energy than washing at one 39.4 inches high.. These figures show the effect of posture on energy costs. They indicate that bending requires more reaching and that less energy was used when the working surface was the correct height for the worker. As more parts of the body were used in work, the amount of energy used gradually increased. The total energy cost increased with the increased speed and that on the basis of efficient cleaning, a speed of 1/2 or 1 foot a second was the most economical of human energy. The total cost of the 1/2,-foot rate was 55.5 calories, and of the 1-foot rate, 79.1 calories. When these speeds were used, the task could be considered light work. There is difference in energy costs when each task was performed in a different body position, or with different kinds of equipment, or at working surfaces of different heights.

On the average, paring potatoes required about 50 percent more energy than resting. Sitting at work in a chair saved some energy, but sitting at work in an uncomfortable position requires more energy. Wringing clothes with an electric wringer took half as much energy as doing it by hand or with a hand-powered wringer. Hanging clothes from a basket on a utility table took much less energy than bending and lifting them from a basket on the floor or ground to hang them. Kneading dough requires about 116 percent more energy than resting, and beating batters requires about 53 percent more.

A classification of homemaking tasks according to their energy demands on the body was set up by Swartz as follows:

According to this classification, paring potatoes, ironing napkins, and beating batter may be classed as light work. Kneading dough and doing most laundry tasks where modern equipment is used are moderately heavy work. Rinsing clothes, hanging them up from a basket on the floor, washing clothes by hand, and wringing with a hand-power wringer are the heavy tasks connected with laundry.

Reaching up with the arms required less energy than bending the body and that the energy consumed was in proportion to height of reach. Reaching down to 3 inches above the floor by trunk bends required less energy than reaching by knee bend. Reaching by knee bend is favored by specialists in body mechanics, however, because it involves less body strain. Information such as this is of value in planning storage space in kitchen work centers and other parts of the house. Type of activity and total time spent in each activity determines to a large extent the body’s need of total energy in term of ‘calories’.

According to world health organization (1974), the energy expenditure (kcal per hour) by men and women for

•  Light work 140 and 100;
•   Moderately active work is 175 and 125;
• Very active work is 240 and 175; and
• Exceptionally heavy work is 300 and 225, respectively.

While lying down, energy expenditure would increase by 3-6%, 8-10% while sitting, 50-60% while standing and stooping and 30 – 40% while kneeling down.

Keeping in view the individual variations in energy expenditure, Durnin and Passmore (1967) categorized the different activities of women as light, moderate and heavy activities as those which require between 1.5 and 3.4; 3.3 and 5.4 and more than 5.4 kcal per minute, respectively. Torun et al. (1982) considered the importance of body weight in defining energy expenditure and expressed the energy cost of different activities on per unit body weight basis as follows:

• Light activities, which required between 0.021 and 0.035 kcal/kg/min;
• Moderate activities, which required between 0.038 an d0.064 kcal/kg/min; and
• Heavy activities which required between 0.072 and 0.089 kcal/kg/min.

The energy cost of different activities are given below in the Table

Energy cost of different activities

Acknowledge of the energy expenditure for various household tasks helps us to plan and manage energy better. This awareness is responsible for the need to alternate light, moderate and heavy work in the daily plan. The total energy spent on an activity is largely dependent on the following factors:

Ø  The number of the part of the body involved in the activity. The energy consumption increases as more parts of the body are involved.

Ø  Sex of the worker: men expend more energy than women for an activity.

Ø   Surface area of the body: larger surface area involves larger expenditure of energy.

Ø   Posture of body at work: bending requires more energy than reaching.

Ø   Height of working surface: this greatly influences energy expenditure.

Ø   Sequence of activity: energy spent is influenced by the sequence of activity.

Ø  Age influences the amount of energy expended. Older people spend more energy than the younger ones.

Ø  Individual differences are also responsible for the amount of energy expended for an activity

Ø  The concentration required for an activity.

Ø   Weather – tropical climates can increase energy expenditure by 5 – 20% (shivering in cold can increase).

A good home-maker not only tries to exploit all energy available but also plans to avoid any wastage of energy. Fatigue lessens one’s capacity to perform subsequent work hence one must plan to avoid wastage of precious energy in energy management. A planning of energy expended or needed for a task and its management is not possible if one does not take into account the factor of fatigue. Fatigue or tiredness results normally if the activity undertaken is beyond one’s capacity. The capacity to work without fatigue varies from person to person. It is also largely dependent upon one’s response to work being done. One tires more easily at work disliked. Fatigue is largely dependent upon one’s approach, postural and muscular strain, concentration involved, skill required, and equipment being used. Fatigue is mainly of two types:

Physiological Fatigue: This results due to the effect of activity on the muscular and nervous system. Any activity undertaken calls for energy, which is provided by the oxidation of nutrient. When there is intense muscular activity the demand for oxygen is higher and the nutrients are reduced to lactic acid (due to incomplete breaking down) and the accumulation of excessive lactic acid in the muscles results in physiological fatigue.

Psychological Fatigue: Psychological fatigue is more concerned with the mental attitude of the worker’s aversion to work. Lacks of interest, boredom are some of the causes of psychological fatigue. Frustration or failure to achieve a goal could also be one of the reasons for this type of fatigue.

There are several ways to reduce both physiological and psychological. Some of these are:

Ø  Providing periods of rest depending upon duration and frequency.

Ø   Undertaking activities as per one’s capacity (both physical and mental).

Ø   Use of energy saving equipment.

Ø  Working in pleasant environment boredom by looking out for ways of making routine, monotonous.

Ø  Avoiding nous and repetitive jobs interesting.

Ø   Motivation to achieve goals involved.

Ø   Avoiding interruptions and unexpected demands.

Ø   Mastering work simplification techniques.

Ø   Including recreation in the work plan.

Ø   Appreciation and feeling of satisfaction.

Conclusion:

It is pointed out that a homemaker person has three basic resources at her disposal: time, money, and energy. Many of today’s homemakers have a double job. A homemaker may hold a position in a profession or in industry for 6 or 8 hours a day, and then have to devote approximately as many more hours to the management and care of her home and family. If she is to take care of both jobs successfully and have any free time and energy left to share in other activities and pleasures, she must accomplish in a comparatively short time ,a maximum amount of work with a minimum of effort. To do this, she must conserve motion and energy. The need to expend energy wisely is undoubtedly becomes important.

Web links

• https://en.oxforddictionaries.com/definition/activity
• www.dictionary.com/browse/calorie
• https://en.wikipedia.org/wiki/Demand
• whatis.techtarget.com › Topics › Computer Science › Electronics
• https://dictionary.cambridge.org/dictionary/english/expenditure
• https://en.oxforddictionaries.com/definition/fatigue
• https://dictionary.cambridge.org/dictionary/english/pedal
• https://dictionary.cambridge.org/dictionary/english/posture
• https://dictionary.cambridge.org/dictionary/english/relation
• https://dictionary.cambridge.org/dictionary/english/strenuous
• https://www.merriam-webster.com/dictionary/torso
• www.dictionary.com/browse/well-being
• www.dictionary.com/browse/wringer