Physical fitness is a state of health and well-being and, more specifically, the ability to perform aspects of sports, occupations and daily activities. Physical fitness is generally achieved through proper nutrition, moderate-vigorous physical exercise, and sufficient rest.
Before the industrial revolution, fitness was defined as the capacity to carry out the day’s activities without undue fatigue. However, with automation and changes in lifestyles physical fitness is now considered a measure of the body's ability to function efficiently and effectively in work and leisure activities, to be healthy, to resist hypokinetic diseases, and to meet emergency situations.
Fitness is defined as the quality or state of being fit. Around 1950, perhaps consistent with the Industrial Revolution and the treatise of World War II, the term "fitness" increased in western vernacular by a factor of ten. Modern definition of fitness describe either a person or machine's ability to perform a specific function or a holistic definition of human adaptability to cope with various situations. This has led to an interrelation of human fitness and attractiveness which has mobilized global fitness and fitness equipment industries. Regarding specific function, fitness is attributed to person who possess significant aerobic or anaerobic ability, i.e. strength or endurance. A well rounded fitness program will improve a person in all aspects of fitness, rather than one, such as only cardio/respiratory endurance or only weight training.
A comprehensive fitness program tailored to an individual typically focuses on one or more specific skills, and on age- or health-related needs such as bone health. Many sources also cite mental, social and emotional health as an important part of overall fitness. This is often presented in textbooks as a triangle made up of three points, which represent physical, emotional, and mental fitness. Physical fitness can also prevent or treat many chronic health conditions brought on by unhealthy lifestyle or aging. Working out can also help some people sleep better and possibly alleviate some mood disorders in certain individuals.
Developing research has demonstrated that many of the benefits of exercise are mediated through the role of skeletal muscle as an endocrine organ. That is, contracting muscles release multiple substances known as myokines which promote the growth of new tissue, tissue repair, and various anti-inflammatory functions, which in turn reduce the risk of developing various inflammatory diseases.
The Physical Activity Guidelines for Americans was created by the Office of Disease Prevention and Health Promotion. This publication suggests that all adults should avoid inactivity to promote good health mentally and physically. For substantial health benefits, adults should participate in at least 150 minutes (two hours and 30 minutes) a week of moderate-intensity, or 75 minutes (1 hour and 15 minutes) a week of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity aerobic activity. Aerobic activity should be performed in episodes of at least 10 minutes, and preferably, it should be spread throughout the week. For additional and more extensive health benefits, adults should increase their aerobic physical activity to 300 minutes (5 hours) a week of moderate-intensity, or 150 minutes a week of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity activity. Additional health benefits are gained by engaging in physical activity beyond this amount. Adults should also do muscle-strengthening activities that are moderate or high intensity and involve all major muscle groups on 2 or more days a week, as these activities provide additional health benefits.
Specific or task-oriented fitness is a person's ability to perform in a specific activity with a reasonable efficiency: for example, sports or military service. Specific training prepares athletes to perform well in their sport.
- 100 m sprint: in a sprint the athlete must be trained to work anaerobically throughout the race, an example of how to do this would be interval training.
- Century Ride: cyclists must be prepared aerobically for a bike ride of 100 miles or more.
- Middle distance running: athletes require both speed and endurance to gain benefit out of this training. The hard working muscles are at their peak for a longer period of time as they are being used at that level for longer period of time.
- Marathon: in this case the athlete must be trained to work aerobically and their endurance must be built-up to a maximum.
- Many fire fighters and police officers undergo regular fitness testing to determine if they are capable of the physically demanding tasks required of the job.
- Members of armed forces will often be required to pass a formal fitness test – for example soldiers of the US Army must be able to pass the Army Physical Fitness Test (APFT).
- Hill sprints: requires a level of fitness to begin with, the exercise is particularly good for the leg muscles. The army often trains doing mountain climbing and races.
- Plyometric and isometric exercises: An excellent way to build strength and increase muscular endurance.
- Sand running creates less strain on leg muscles than running on grass or concrete. This is because sand collapses beneath the foot softening the landing. Sand training is an effective way to lose weight and become fit as its proven you need more effort (one and a half times more) to run on the soft sand than on a hard surface.
- Aquajogging is a form of exercise that decreases strain on joints and bones. The water supplies minimal impact[clarification needed] to muscles and bones which is good for those recovering from injury. Furthermore, the resistance of the water as one jogs through it provides an enhanced effect of exercise (the deeper you are the greater the force needed to pull your leg through).
In order for physical fitness to benefit the health of an individual, an unknown response in the person called a stimulus will be triggered by the exertion. When exercise is performed with the correct amount of intensity, duration and frequency, a significant amount of improvement can occur. The person may overall feel better but the physical effects on the human body take weeks or months to notice and possibly years for full development. For training purposes, exercise must provide a stress or demand on either a function or tissue. To continue improvements, this demand must eventually increase little over an extended period of time. This sort of exercise training has three basic principles: overload, specificity, and progression. These principles are related to health but also enhancement of physical working capacity.
High intensity interval training
High intensity interval training (HIIT) consists of repeated, short bursts of exercise, completed at a high level of intensity. These sets of intense activity are followed by a predetermined time of rest or low intensity activity. Studies have shown that exercising at a higher intensity has increased cardiac benefits for humans, compared to when exercising at a low or moderate level. When your workout consists of an HIIT session, your body has to work harder to replace the oxygen it lost. Research into the benefits of HIIT have revealed that it can be very successful for reducing fat, especially around the abdominal region. Furthermore, when compared to continuous moderate exercise, HIIT proves to burn more calories and increase the amount of fat burned post- HIIT session. Lack of time is one of the main reasons stated for not exercising; HIIT is a great alternative for those people because the duration of an HIIT session can be as short as 10 minutes, making it much quicker than conventional workouts.
Cardiorespiratory fitness can be measured using VO2 max, a measure of the amount of oxygen the body can uptake and utilize. Aerobic exercise, which improves cardiorespiratory fitness, involves movement that increases the heart rate to improve the body's oxygen consumption. This form of exercise is an important part of all training regiments ranging from professional athletes to the everyday person. Also, it helps increase stamina.
- Jogging – Running at a steady and gentle pace. This form of exercise is great for maintaining weight.
- Elliptical Training – This is a stationary exercise machine used to perform walking, or running without causing excessive stress on the joints. This form of exercise is perfect for people with achy hips, knees and ankles.
- Walking – Moving at a fairly regular pace for a short, medium or long distance.
- Treadmill training – Many treadmills have programs set up that offer numerous different workout plans. One effective cardiovascular activity would be to switch between running and walking. Typically warm up first by walking and then switch off between walking for three minutes and running for three minutes.
- Swimming – Using the arms and legs to keep oneself afloat and moving either forwards or backwards. This is a good full body exercise for those who are looking to strengthen their core while improving cardiovascular endurance.
- Cycling – Riding a bicycle typically involves longer distances than walking or jogging. This is another low stress exercise on the joints and is great for improving leg strength.
- Sprinting - Running short distances as fast as possible
Controlling blood pressure
Physical fitness has proven to result in positive effects on the body's blood pressure because staying active and exercising regularly builds up a stronger heart. The heart is the main organ in charge of systolic blood pressure and diastolic blood pressure. Engaging in a physical activity will create a rise in blood pressure, once the activity is stopped, however, the individual’s blood pressure will return to normal. The more physical activity that one engages in, the easier this process becomes, resulting in a more ‘fit’ individual. Through regular physical fitness, the heart does not have to work as hard to create a rise in blood pressure, which lowers the force on the arteries, and lowers the over all blood pressure.
Centers for disease control and prevention provide lifestyle guidelines of maintaining a balanced diet and engaging in physical activity to reduce the risk of disease. The WCRF/ American Institute for Cancer Research (AICR) published a list of recommendations that reflect the evidence they have found through consistency in fitness and dietary factors that directly relate to Cancer prevention.
The WCRF/AICR recommendations include the following:
- Be as lean as possible without becoming underweight
- Each week, adults should engage in at least 150 minutes of moderate intensity physical activity or 75 minutes of vigorous intensity physical activity
- Children should engage in at least one hour of moderate or vigorous physical activity each week
- Be physically active for at least thirty minutes every day
- Avoid sugar, limit the consumption of energy packed foods
- Balance your diet with a variety of vegetables, grains, fruits, legumes, etc.
- Limit sodium intake, the consumption of red meats and the consumption of processed meats
- Limit alcoholic drinks to two for men and one for women a day"
These recommendations are also widely supported by the American Cancer Society. The guidelines have been evaluated and individuals that have higher guideline adherence scores substantially reduce cancer risk as well as help towards control with a multitude of chronic health problems. Regular physical activity is a factor that helps reduce an individual’s blood pressure and improves cholesterol levels, two key components that correlate with heart disease and Type 2 Diabetes. The American Cancer Society encourages the public to "adopt a physically active lifestyle" by meeting the criteria in a variety of physical activities such as hiking, swimming, circuit training, resistance raining, lifting, etc. It is understood that cancer is not a disease that can be cured by physical fitness alone, however because it is a multifactorial disease, physical fitness is a controllable prevention. The large associations tied with being physically fit and reduced cancer risk are enough to provide a strategy to reduce cancer risk. The American Cancer Society assorts different levels of activity ranging from moderate to vigorous to clarify the recommended time spent on a physical activity. These classifications of physical activity consider the intentional exercise and basic activities done on a daily basis and give the public a greater understanding by what fitness levels suffice as future disease prevention.
Studies have shown an association between increased physical activity and reduced inflammation. It produces both a short-term inflammatory response and a long-term anti-inflammatory effect. Physical activity reduces inflammation in conjunction with or independent of changes in body weight. However, the mechanisms linking physical activity to inflammation are unknown.
Physical activity boosts the immune system. This is dependent on the concentration of endogenous factors (such as sex hormones, metabolic hormones and growth hormones), body temperature, blood flow, hydration status and body position. Physical activity has shown to increase the levels of natural killer (NK) cells, NK T cells, macrophages, neutrophils and eosinophils, complements, cytokines, antibodies and T cytotoxic cells. However, the mechanism linking physical activity to immune system is not fully understood.
Achieving resilience through physical fitness promotes a vast and complex range of health related benefits. Individuals who keep up physical fitness levels generally regulate their distribution of body fat and stay away from obesity. Abdominal fat, specifically visceral fat, is most directly affected by engaging in aerobic exercise. Strength training has been known to increase the amount of muscle in the body, however it can also reduce body fat. Sex steroid hormones, insulin, and an appropriate immune response are factors that mediate metabolism in relation to the abdominal fat. Therefore, physical fitness provides weight control through regulation of these bodily functions.
Menopause and physical fitness
Menopause is the term that is used to refer to the stretch of both before and after a woman's last menstrual cycle. There are an instrumental amount of symptoms connected to menopause, most of which can affect the quality of life of the women involved in this stage of her life. One way to reduce the severity of the symptoms is exercise and keeping a healthy level of fitness. Prior to and during menopause as the female body changes there can be physical, physiological or internal changes to the body. These changes can be prevented or even reduced with the use of regular exercise. These changes include:
- Prevention of weight gain: around menopause women tend to experience a reduction in muscle mass and an increase in fat levels. Slight increases in physical exercise can help to prevent these changes.
- Reduce the risk of breast cancer: due to the weight loss from regular exercise may offer protection from breast cancer.
- Strengthen the bones: Physical activity can slow the bone loss associated with menopause, reducing the chance of bone fractures and osteoporosis.
- Reduce the risk of disease: Excess weight can increase the risk of heart disease and type 2 diabetes, and the regular physical activity can counter these effects.
- Boost the mood: By being involved in regular activities it can improve the psychological health, this can be the case at any age and not only for times during or after menopause.
The Melbourne Women's Midlife Health Project provided evidence that showed over an eight-year time period 438 were followed. Even though the physical activity was not associated with VMS in this cohort at the beginning. Women who reported they were physically active everyday at the beginning were 49% less likely to have reported bothersome hot flushes. This is in contrast to women whose level of activity decreased and were more likely to experience bothersome hot flushes.
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According to the United States Department of Health and Human Services, physical fitness is defined as "a set of attributes that people have or achieve that relates to the ability to perform physical activity."
This description goes beyond being able to run fast or lift heavy weights. Despite being important, these attributes only address single areas of fitness. This article provides details of the five main components of physical fitness.
- Maintaining physical fitness can help prevent some diseases.
- With exercise, body composition can change without changing weight.
- Athletes' hearts show different changes dependent on their chosen sport.
- Muscle strength increases by fiber hypertrophy and neural changes.
- Stretching to increase flexibility can ease a number of medical complaints.
Being physically fit depends on how well a person fulfills each of the components of being healthful.
When it comes to fitness, these components include
- cardiorespiratory fitness
- muscular strength
- muscular endurance
- body composition
So, you can tell if someone is physically fit by determining how well they perform in each component.
Here we will look at them all individually.
Cardiorespiratory endurance indicates how well our body can supply fuel during physical activity via the body's circulatory and respiratory systems. Activities that help improve cardiorespiratory endurance are those that cause an elevated heart rate for a sustained period.
These activities include:
- brisk walking
People who regularly take part in these activities are more likely to be physically fit in terms of cardiorespiratory endurance. It is important to begin these activities slowly and gradually increase the intensity.
Exercising increases cardiorespiratory endurance in a number of ways. The heart muscle is strengthened so that it is able to pump more blood per heartbeat.
At the same time, additional small arteries are grown within muscle tissue so that blood can be delivered to working muscles more effectively when needed.
How does heart health change with exercise?
The heart changes and improves its efficiency after persistent training. However, more recent research shows that different types of activity change the heart in subtly different ways.
All types of exercise increase the heart's overall size, but there are significant differences between endurance athletes, like rowers, and strength athletes, like football players. Endurance athletes' hearts show expanded left and right ventricles, whereas strength athletes show thickening of their heart wall, particularly the left ventricle.
How does lung health change with exercise?
While the heart steadily strengthens over time, the respiratory system does not adjust to the same degree. Lung function does not drastically change, but oxygen that is taken in by the lungs is used more effectively.
In general, exercise encourages the body to become more efficient at taking on, distributing, and using oxygen. This improvement, over time, increases endurance and overall health.
The American College of Sports Medicine recommends aerobic exercise 3-5 times per week for 30-60 minutes, at an intensity that keeps the heart rate at 65-85 percent of the maximum heart rate.
Health benefits of cardiorespiratory fitness
Cardiorespiratory fitness has been found to help reduce the risk of conditions including:
The U.S. Department of Health and Human Services defines muscular strength as "the ability of muscle to exert force during an activity."
There are a number of ways to measure muscular strength. Generally, lifting or pushing something of a set weight in a prescribed position and comparing the results against any given population is the best way.
In general, if a muscle is worked consistently and regularly, it will increase in strength. There are various ways of putting your muscles through rigorous activity, but anything that works a muscle until it is tired will increase muscle strength over time.
How does muscle structure change with exercise?
Muscles consist of elongated muscle cells. Each muscle cell contains contractile proteins - actin and myosin - that give the muscle its strength. These fibers contract together, producing the so-called power stroke. The total force depends on the number of these units contracting in unison.
To build muscle, the following criteria must be met:
- muscles are regularly exercised
- the individual has taken in enough protein
The exact mechanism of muscle building is not fully understood, but the general principles are well known. Training causes the muscle cells to expand and there is an increase in actin and myosin production.
Also, in untrained muscles, fibers tend to fire in an asynchronous manner - in other words, they do not fire in unison. As they become trained, they learn to fire together as one, increasing maximum power output.
Normally, the body prevents the muscles from over-exerting themselves and becoming injured. As the muscle is trained, the body starts to disinhibit the muscles' activation - more power is allowed to be exerted.
Fitness can include muscular endurance, which is the ability of a muscle to continue exerting force without tiring. As mentioned above, strength training builds bigger muscles. Endurance training, on the other hand, does not necessarily generate muscles of a larger size.
This is because the body focuses more on the cardiovascular system, ensuring that the muscles receive the oxygenated blood they need to keep functioning. Another important change in muscles that are specifically trained for endurance concerns the different types of muscle tissue - fast twitch and slow twitch fibers:
Fast twitch fibers - contract quickly but get tired quickly. They use a lot of energy and are useful for sprints. They are whitish in color as they do not require blood to function.
Slow twitch fibers - best for endurance work, they can carry out tasks without getting tired. They are found in core muscles. These fibers appear red as they rely on a good supply of oxygenated blood and contain stores of myoglobin.
Different exercises will promote fast twitch fibers, slow twitch fibers, or both. A sprinter will have comparatively more fast twitch fibers, whereas a long distance runner will have more slow twitch fibers.
Body composition measures the relative amounts of muscle, bone, water, and fat.
An individual can potentially maintain the same weight but radically change the ratio of each of the components that make up the body.
For instance, people with a high muscle (lean mass) ratio weigh more than those with the same height and waist circumference who have less muscle. Muscle weighs more than fat.
physiology/pb03.html" target="_blank">depends on the activity that the individual is being trained to carry out.
These measurements of body fat content were taken from high-level sportsmen and women of different disciplines:
- Basketball - men 9 percent and women 13 percent
- Cross-country skiing - men 5 percent and women 11 percent
- Golf - men 13 percent and women 16 percent
- Kayaking/Canoeing - men 13 percent and women 22 percent
- Swimming - men 12 percent and women 19 percent
- 100-, 200- and 400-meter racers - men 6.5 percent and women 14 percent
- Boxing - men 7 percent
- Wrestling - men 8 percent
How is body composition calculated?
Caclulating body composition accurately can be a painstaking task. There are a number of accurate methods, this is just one:
First, weight is measured on standard scales. Next, volume is measured by submerging the individual in water and measuring the displacement.
The proportions of water, protein, and mineral in the body can be ascertained by various chemical and radiometric tests. The densities of water, fat, protein, and mineral are either measured or estimated.
The numbers are then entered into the following equation:
1/Db = w/Dw + f/Df + p/Dp + m/Dm
Where: Db = overall body density, w = proportion of water, f = proportion of fat, p = proportion of protein, m = proportion of mineral, Dw = density of water, Df = density of fat, Dp = density of protein, Dm = density of mineral.
Other methods include dual energy X-ray absorptiometry, air displacement plethysmography, bioelectrical impedance analysis, total body imaging (MRI and CT), and ultrasound.
Flexibility is the range of movement across a joint. Flexibility is important because it improves the ability to link movements together smoothly and can help prevent injuries. Flexibility is specific to each joint and depends on a number of variables, including the tightness of ligaments and tendons.
Flexibility is increased by various activities, all designed to stretch joints, ligaments, and tendons. There are three types of exercise that are generally utilized to increase flexibility:
- Dynamic stretching - the ability to complete a full range of motion of a particular joint. This type of flexibility is used in standard "warming up" exercises as it helps ready the body for physical activity.
- Static-active stretching - holding the body or part of the body in a stretched position and maintaining that position for a period of time. One example of static-active stretching is the splits.
- Ballistic stretching - only to be used when the body is already warmed up and limber from exercise, it involves stretching in various positions and bouncing.
There are a number of ways to improve flexibility. A daily stretching regimen can be the simplest and most efficient way of achieving whole body flexibility.
In general, fitness means different things to different people. The important take-home message is that embarking on any regular exercise will be of benefit to your health. The more exercise that is carried out, the healthier an individual will look and feel..a>