Physical fitness

Physical fitness is used in two close meanings: general fitness (a state of health and well-being) and specific fitness (a task-oriented definition based on the ability to perform specific aspects of sports or occupations).

Physical fitness is the capacity of the heart, blood vessels, lungs, and muscles to function at optimum efficiency. In previous years, fitness was defined as the capacity to carry out the day’s activities without undue fatigue. Automation increased leisure time, and changes in lifestyles following the industrial revolution meant this criterion was no longer sufficient. Optimum efficiency is the key. Physical fitness is now defined as 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 can also be divided into five categories aerobic fitness, muscular strength, muscular endurance, flexibility, and body composition.

General fitness
* Accuracy
* Agility
* Balance
* Body composition
* Cardiovascular endurance
* Coordination
* Flexibility and joint range of motion
* Power
* Speed
* Stamina
* Strength

Many sources also cite mental and emotional health as an important part of overall fitness. This is often presented in textbooks as a triangle made up of three sub-sections, which represent physical, emotional, and mental fitness. Hence, one may be physically fit but may still suffer from a mental illness or have emotional problems. The "ideal triangle" is balanced in all areas. Physical fitness can also prevent or treat many chronic health conditions brought on by unhealthy lifestyle or aging, among other implications. To stay healthy it's important to participate in physical activity.

Specific fitness
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 sports.

Examples are:

* 400m sprint - in a sprint the athlete must be trained to work anaerobically throughout the race.
* Marathon - in this case the athlete must be trained to work aerobically and their endurance must be built-up to a maximum.

Fire fighters and police officers must undergo regular Fitness testing to determine if they are capable of the physically demanding tasks required for the job before they are employed.

Mental Health

Mental health refers to a human individual's emotional and psychological well-being. Merriam-Webster defines mental health as "A state of emotional and psychological well-being in which an individual is able to use his or her cognitive and emotional capabilities, function in society, and meet the ordinary demands of everyday life."

According to the World Health Organization, there is no one "official" definition of mental health. Cultural differences, subjective assessments, and competing professional theories all affect how "mental health" is defined. In general, most experts agree that "mental health" and "mental illness" are not opposites. In other words, the absence of a recognized mental disorder is not necessarily an indicator of mental health.

One way to think about mental health is by looking at how effectively and successfully a person functions. Feeling capable and competent; being able to handle normal levels of stress, maintain satisfying relationships, and lead an independent life; and being able to "bounce back," or recover from difficult situations, are all signs of mental health.

Encompassing your emotional, social, and—most importantly—your mental well-being; All these aspects—emotional, physical, and social—must function together to achieve overall health.

Health maintenance

Self care

Achieving health and remaining healthy is an active process. Effective strategies for staying healthy and improving one's health include the following elements:

Nutrition
The updated USDA food pyramid, published in 2005, is a general nutrition guide for recommended food consumption.

Nutrition is the science that studies how what people eat affects their health and performance, such as foods or food components that cause diseases or deteriorate health (such as eating too many calories, which is a major contributing factor to obesity, diabetes, and heart disease). The field of nutrition also studies foods and dietary supplements that improve performance, promote health, and cure or prevent disease, such as eating fibrous foods to reduce the risk of colon cancer, or supplementing with vitamin C to strengthen teeth and gums and to improve the immune system.

Personal health depends partially on the social structure of one’s life. The maintenance of strong social relationships is linked to good health conditions, longevity, productivity, and a positive attitude. This is due to the fact that positive social interaction as viewed by the participant increases many chemical levels in the brain which are linked to personality and intelligence traits. Essentially this means that positive reinforcement from a third party make one more socially adept, in control, and relaxed physically and mentally, all of which are proven to effect the nervous system(UHF).

Sports nutrition
Sports nutrition focuses on how food and dietary supplements affect athletic performance (during events), improvement (from training), and recovery (after events and training). One goal of sports nutrition is to maintain glycogen levels and prevent glycogen depletion. Another is to optimize energy levels and muscle tone. An athlete's strategy for winning an event may include a schedule for the entire season of what to eat, when to eat it, and in what precise quantities (before, during, after, and between workouts and events). Participants in endurance sports such as the full-distance triathlon actually eat during their races. Sports nutrition works hand-in-hand with sports medicine.

Exercise
Exercise is the performance of movements in order to develop or maintain physical fitness and overall health. It is often directed toward also honing athletic ability or skill. Frequent and regular physical exercise is an important component in the prevention of some of the diseases of affluence such as cancer, heart disease, cardiovascular disease, Type 2 diabetes, obesity and back pain.

Exercises are generally grouped into three types depending on the overall effect they have on the human body:

* Flexibility exercises such as stretching improve the range of motion of muscles and joints.
* Aerobic exercises such as walking and running focus on increasing cardiovascular endurance and muscle density.
* Anaerobic exercises such as weight training or sprinting increase muscle mass and strength.

Physical exercise is considered important for maintaining physical fitness including healthy weight; building and maintaining healthy bones, muscles, and joints; promoting physiological well-being; reducing surgical risks; and strengthening the immune system.

Proper nutrition is just as, if not more, important to health as exercise. When exercising it becomes even more important to have good diet to ensure the body has the correct ratio of macronutrients whilst providing ample micronutrients; this is to aid the body with the recovery process following strenuous exercise. When the body falls short of proper nutrition, it gets into starvation mode developed through evolution and depends onto fat content for survival. Research suggest that the production of thyroid hormones can be negatively affected by repeated bouts of dieting and calorie restriction. Proper rest and recovery is also as important to health as exercise, otherwise the body exists in a permanently injured state and will not improve or adapt adequately to the exercise.

The above two factors can be compromised by psychological compulsions (eating disorders such as exercise bulimia, anorexia, and other bulimias), misinformation, a lack of organization, or a lack of motivation. These all lead to a decreased state of health.

Delayed Onset Muscle Soreness can occur after any exercise, particularly if the body is in an unconditioned state relative to that exercise and the exercise involves repetitive eccentric contractions.

Hygiene
Hygiene is the practice of keeping the body clean to prevent infection and illness, and the avoidance of contact with infectious agents. Hygiene practices include bathing, brushing and flossing teeth, washing hands especially before eating, washing food before it is eaten, cleaning food preparation utensils and surfaces before and after preparing meals, and many others. This may help prevent infection and illness. By cleaning the body, dead skin cells are washed away with the germs, reducing their chance of entering the body.

Stress management
Prolonged psychological stress may negatively impact health, such as by weakening the immune system. See negative effects of the fight-or-flight response. Stress management is the application of methods to either reduce stress or increase tolerance to stress. Certain nootropics do both. Exercising to improve physical fitness, especially cardiovascular fitness, boosts the immune system and increases stress tolerance. Relaxation techniques are physical methods used to relieve stress. Examples include sexual intercourse, progressive relaxation, and fractional relaxation. Psychological methods include cognitive therapy, meditation, and positive thinking which work by reducing response to stress. Improving relevant skills and abilities builds confidence, which also reduces the stress reaction to situations where those skills are applicable. Reducing uncertainty, by increasing knowledge and experience related to stress-causing situations, has the same effect. Learning to cope with problems better, such as improving problem solving and time management skills, may also reduce stressful reaction to problems. Repeatedly facing an object of one's fears may also desensitize the fight-or-flight response with respect to that stimulus -- e.g., facing bullies may reduce fear of bullies.

Health care
Health care is the prevention, treatment, and management of illness and the preservation of mental and physical well being through the services offered by the medical, nursing, and allied health professions. According to the World Health Organization, health care embraces all the goods and services designed to promote health, including “preventive, curative and palliative interventions, whether directed to individuals or to populations”. The organized provision of such services may constitute a health care system. This can include a specific governmental organization such as the National Health Service in the UK, or a cooperation across the National Health Service and Social Services as in Shared Care.

Workplace wellness programs
Workplace wellness programs are recognized by an increasingly large number of companies for their value in improving the health and well-being of their employees, and for increasing morale, loyalty, and productivity. Workplace wellness programs can include things like onsite fitness centers, health presentations, wellness newsletters, access to health coaching, tobacco cessation programs and training related to nutrition, weight and stress management. Other programs may include health risk assessments, health screenings and body mass index monitoring. Mostly overseen or not mentioned is a group of determinants of health which could be called coincidence, hazard, luck or bad luck. These factors are quite important determinants of health but difficult to calculate.

Public health

Public health is the study and practice of managing threats to the health of a community. The field pays special attention to the social context of disease and health, and focuses on improving health through society-wide measures like vaccinations, the fluoridation of drinking water, or through policies like seatbelt and non-smoking laws.

The goal of public health is to improve lives through the prevention and treatment of disease. The United Nations' World Health Organization defines health as "a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity." In 1920, C.E.A. Winslow defined public health as "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals."

The public-health approach can be applied to a population of just a handful of people or to the whole human population. Public health is typically divided into epidemiology, biostatistics and health services. Environmental, social, behavioral, and occupational health are also important subfields.

Modern Public Health

As the prevalence of infectious diseases in the developed world decreased through the 20th century, public health began to put more focus on chronic diseases such as cancer and heart disease. An emphasis on physical exercise was reintroduced.

In America, public health worker Dr. Sara Josephine Baker lowered the infant mortality rate using preventative methods. She established many programs to help the poor in New York City keep their infants healthy. Dr. Baker led teams of nurses into the crowded neighborhoods of Hell's Kitchen and taught mothers how to dress, feed, and bathe their babies. After World War I many states and countries followed her example in order to lower infant mortality rates.

During the 20th century, the dramatic increase in average life span is widely credited to public health achievements, such as vaccination programs and control of infectious diseases, effective safety policies such as motor-vehicle and occupational safety, improved family planning, fluoridation of drinking water, anti-smoking measures, and programs designed to decrease chronic disease.

Meanwhile, the developing world remained plagued by largely preventable infectious diseases, exacerbated by malnutrition and poverty. Front-page headlines continue to present society with public health issues on a daily basis: emerging infectious diseases such as SARS, making its way from China to Canada and the United States; prescription drug benefits under public programs such as Medicare; the increase of HIV-AIDS among young heterosexual women and its spread in South Africa; the increase of childhood obesity and the concomitant increase in type II diabetes among children; the impact of adolescent pregnancy; and the ongoing social, economic and health disasters related to the 2005 Tsunami and Hurricane Katrina in 2006. These are all ongoing public health challenges.

Since the 1980s, the growing field of population health has broadened the focus of public health from individual behaviors and risk factors to population-level issues such as inequality, poverty, and education. Modern public health is often concerned with addressing determinants of health across a population, rather than advocating for individual behaviour change. There is a recognition that our health is affected by many factors including where we live, genetics, our income, our educational status and our social relationships - these are known as "social determinants of health." A social gradient in health runs through society, with those that are poorest generally suffering the worst health. However even those in the middle classes will generally have worse health outcomes than those of a higher social stratum (WHO, 2003). The new public health seeks to address these health inequalities by advocating for population-based policies that improve the health of the whole population in an equitable fashion.

The burden of treating conditions caused by unemployment, poverty, unfit housing and environmental pollution have been calculated to account for between 16-22% of the clinical budget of the British National Health Service.

UK Public health functions include:

* Health surveillance, monitoring and analysis
* Investigation of disease outbreaks, epidemics and risk to health
* Establishing, designing and managing health promotion and disease prevention programmes
* Enabling and empowering communities to promote health and reduce inequalities
* Creating and sustaining cross-Government and intersectoral partnerships to improve health and reduce inequalities
* Ensuring compliance with regulations and laws to protect and promote health
* Developing and maintaining a well-educated and trained, multi-disciplinary public health workforce
* Ensuring the effective performance of NHS services to meet goals in improving health, preventing disease and reducing inequalities
* Research, development, evaluation and innovation
* Quality assuring the public health function

Environmental health

Environmental health is the branch of public health that is concerned with all aspects of the natural and built environment that may affect human health. Other terms that refer to the discipline of environmental health include environmental public health and environmental health and protection.

Environmental health is defined by the World Health Organisation as:

Those aspects of human health and disease that are determined by factors in the environment. It also refers to the theory and practice of assessing and controlling factors in the environment that can potentially affect health.

Environmental health as used by the WHO Regional Office for Europe, includes both the direct pathological effects of chemicals, radiation and some biological agents, and the effects (often indirect) on health and wellbeing of the broad physical, psychological, social and aesthetic environment which includes housing, urban development, land use and transport.

Environmental health services
Environmental health services are defined by the World Health Organisation as:

those services which implement environmental health policies through monitoring and control activities. They also carry out that role by promoting the improvement of environmental parameters and by encouraging the use of environmentally friendly and healthy technologies and behaviours. They also have a leading role in developing and suggesting new policy areas.

Environmental health practitioners may be known as sanitarians, public health inspectors, environmental health specialists or environmental health officers. Many states in the United States require that individuals have professional licenses in order to practice environmental health. California state law defines the scope of practice of environmental health as follows:

"Scope of practice in environmental health" means the practice of environmental health by registered environmental health specialists in the public and private sector within the meaning of this article and includes, but is not limited to, organization, management, education, enforcement, consultation, and emergency response for the purpose of prevention of environmental health hazards and the promotion and protection of the public health and the environment in the following areas: food protection; housing; institutional environmental health; land use; community noise control; recreational swimming areas and waters; electromagnetic radiation control; solid, liquid, and hazardous materials management; underground storage tank control; onsite septic systems; vector control; drinking water quality; water sanitation; emergency preparedness; and milk and dairy sanitation.

The environmental health profession had its modern-day roots in the sanitary and public health movement of the United Kingdom. This was epitomized by Sir Edwin Chadwick, who was instrumental in the repeal of the poor laws and was the founding president of the Association of Public Sanitary Inspectors in 1884, which today is the Chartered Institute of Environmental Health.

Environmental health concerns
Environmental health addresses all human-health-related aspects of both the natural environment and the built environment. Environmental health concerns include:

* Air quality, including both ambient outdoor air and indoor air quality, which also comprises concerns about environmental tobacco smoke.

* Body art safety, including tattooing, body piercing and permanent cosmetics.

* Climate change and its effects on health.

* Disaster preparedness and response.

* Food safety, including in agriculture, transportation, food processing, wholesale and retail distribution and sale.

* Hazardous materials management, including hazardous waste management, contaminated site remediation, the prevention of leaks from underground storage tanks and the prevention of hazardous materials releases to the environment and responses to emergency situations resulting from such releases.

* Housing, including substandard housing abatement and the inspection of jails and prisons.

* Childhood lead poisoning prevention.

* Land use planning, including smart growth.

* Liquid waste disposal, including city wastewater treatment plants and on-site waste water disposal systems, such as septic tank systems and chemical toilets.

* Medical waste management and disposal.

* Noise pollution control.

* Occupational health and industrial hygiene.

* Radiological health, including exposure to ionizing radiation from X-rays or radioactive isotopes.

* Recreational water illness prevention, including from swimming pools, spas and ocean and freshwater bathing places.

* Safe drinking water.

* Solid waste management, including landfills, recycling facilities, composting and solid waste transfer stations.

* Toxic chemical exposure whether in consumer products, housing, workplaces, air, water or soil.

* Vector control, including the control of mosquitoes, rodents, flies, cockroaches and other animals that may transmit pathogens.

Role of science in health

Health scienceHealth science is the branch of science focused on health, and it includes many subdisciplines. There are two approaches to health science: the study and research of the human body and health-related issues to understand how humans (and animals) function, and the application of that knowledge to improve health and to prevent and cure diseases.

Where health knowledge comes from
Health research builds primarily on the basic sciences of biology, chemistry, and physics as well as a variety of multidisciplinary fields (for example medical sociology). Some of the other primarily research-oriented fields that make exceptionally significant contributions to health science are biochemistry, epidemiology, and genetics.

Putting health knowledge to use
Applied health sciences also endeavor to better understand health, but in addition they try to directly improve it. Some of these are: biomedical engineering, biotechnology, nursing, nutrition, pharmacology, pharmacy, public health, psychology, physical therapy, and medicine. The provision of services to maintain or improve people's health is referred to as health care.