Karen Chan Yuk Ying 6S 22 Bio essay ~~ Health

After the outbreak of SARS, more people concern their health and do more things to keep themselves healthy. Actually, most people do not know what health means. Health means ¡§a state of complete physical, social and mental well-being, and not merely the absence of disease or infirmly¡¨. Therefore, we need to adopt good practices, which contribute to physical health.

Having a balanced diet is very important. If we eat too little, deficiency diseases may result. Yet it is equally unhealthy if we eat too much or have a bias towards certain foods. A balanced diet contains all the seven groups of food substances in the right amount for our age and gender. The amount of food substances we need varies with age, sex, body size, occupation and physical activity. For example, a growing child needs more proteins than an old man who is no longer growing. A pregnant woman needs more protein, carbohydrates, minerals and vitamins for herself and her baby. Therefore, different people should have different diet with the others.

Doing exercise can make our body healthy. The amount of work the muscles can perform is limited by the amount of oxygen obtained during ventilation, and the efficiency of the cardiovascular system in supplying oxygen to the muscles. Studies reveal that 30 minutes of physical activity of moderate intensity everyday is beneficial to health. It can improve your heart-lung function and blood circulation, reduce the risk of developing coronary heart disease, high blood pressure and diabetes later in life, it helps to build up body resistance and is important in maintaining bone health, it can aid you to control body weight and is good for your psychological and social health.

After doing exercise, taking a rest is also very important to keep ourselves healthy. It is because continual activity especially muscular activity for a sustained period leads to accumulation of toxic waste and depletion of food reserve. So rest can allow the exhausted cells to undergo a period of inactivity or low activity for removing toxic waste and replenish the food reserve in the cells.

Smoking and alcohol abuse will affect our health. Excessive alcohol consumption can lead to alcohol dependency. Furthermore, it may cause numerous health problems. Alcohol is a sedative. It affects the co-ordination of the body's movement, impairs judgment and slows down your responses. It provides the body with necessary calories, but has no nutritional value, therefore excessive drinking causes malnutrition. Alcohol also affects your digestive system, causing oesophagitis, chronic gastritis, gastric ulcers, and so on. Alcohol also damages your liver, causing hepatitis, cirrhosis, and even liver cancer. Alcohol raises blood pressure, causes enlargement of heart and eventually heart failure.

Cigarette smoke contains many harmful substances included nicotine, which affects the central nervous system and causes addiction, carbon monoxide that impedes the body's absorption of oxygen, lowering exercise endurance, and speeding up the aging process. Tar in the smoke can cause cancer. It also increases coughing and production of sputum. It turns smoker's fingers and teeth yellow. Smoking is closely associated with emphysema and chronic bronchitis. In addition, it increases the risk of lung cancer, heart disease, and gastric ulcers.

To have a more healthy life and body, get rid of these harmful things e.g. smoking and alcohol abuse. Having a balanced diet, doing enough exercise and taking rest are good for people so we should have a good habit included these.