Our body is the only source to do all the works of our life. We need body to do religious, economical, social, moral and spiritual works. Therefore, we need to remain healthy. It has been said that- 
‘Shariramadyamkhalu dharma sadhanam I’
Physical health means not only healthy body but healthy entire personality also. There are four ingredients of it-
1)    Physical
2)    Mental
3)    Economical
4)    Spiritual

Physical health

As its name, body needs to be healthy first. Because no work is possible without healthy body whether it is enjoying worldly prosperity or attaining spiritual bliss. Two things are important for keeping body healthy-
1)    Diets contribute around 70 percent in keeping body healthy. 
2)    Daily exercise contributes around 30 percent in keeping body healthy. 
Therefore, we need to control on our diets and avoid fried and packaged food items, maida, etc. Always keep in mind to consume light diet. Chew the food. The brain gets its message after 20 minutes.  
Do exercise daily and regularly. Try to do exercise of all the body organs. Try to do exercise in various postures so that body can function properly. 
However, it would be justifiable that we do exercise and consume diets under guidance of any expert. Otherwise, many a times, it makes adverse effect on our body. Yogic postures are highly useful for exercise. But as we know that postures give no desired benefit without abiding by yam and niyam. Therefore, yog is not an exercise but a mean of leading a healthy life. 

Mental health

Few years ago, people used to give no proper attention on the mental health. Even today in the rural areas, people prefer not to talk on mental health. In the urban areas too, people conceal it to avoid getting treated themselves as insane. It needs to be understood that as mind also falls prey to diseases in line with body. Therefore, we also need to keep mind healthy. Mind plays an important role in doing any work. It has been said-
‘If mind wins, we win battle, if mind loses, we lose battle’
We need to keep two things in mind to keep our mind healthy-
1)    Pranayam
2)    Reading knowledgeable books
We need to read good books. It has been said that books are the best friends of the human beings.
Mental health includes emotional health which comprises information regarding yourself, awareness, social awareness and building relationship, etc. Emotional intellect means helping others, listening them patiently, encouraging yourself continuously, controlling your emotions, etc. It’s possible only through pranayam and exercise.

Economical health

We need to be financially empowered to leading a healthy life. It’s possible only through hard labour. Without economically self-reliant, other activities of life get derailed. Therefore, the scholars treat homely life as the best way. It’s the best ashram of all. Therefore, we need to acquire knowledge properly in the celibacy ashram so that we need to earn money as per the religion in future. It has been said-

‘Arthagamonityamarogita cha, priya cha bharyapriyavadini cha,
Vashyashchaputraarthakari cha vidya, shad jivalokasyasukhanirajan I’

It means that those people who have enough money, healthy body, loving brothers, obedient sons and daughters and knowledge are prosperous in the world. 
Economic freedom in the celibacy ashram means acquiring more knowledge in the limited resources. Those students who visit to foreign universities to study are allowed to do few hours of work for earning money so that they can know importance of money in their life. 

Spiritual health

Spiritual health doesn’t mean that you remain offering prayer to the god. It means that you must know aims and objectives of life. You must participate in good thoughts of the society. You must contribute in social welfare. Your life should be based on values. 

Truth, non-violence, asteya, aprigrah, celibacy, tap, satisfaction, self-study, remembrance of the god, kindness, forgiveness, donation, duty, etc are some of the good merits which need to be assimilated in our life. These are highly important for overall development of our life. Proper path is essential for getting success in life. Otherwise, we will get derailed.
Coordination of all the four areas is essential for health. Generally, people consider that earning money, conservation of divine or moral values and study should be in homely asram, sanyas and celibacy respectively. it has been said that-

Prathamenarjita vidya, dvitiyenarjitamdhanam,
Tritiyenarjitampunyam, chartuthekimkarishyati I

It means that those people who didn’t acquire knowledge, money and divinity in celibacy, homely ashram and sanyas respectively can do nothing in vanprashtha. But it’s not proper in the practical. We need to keep coordination of all the four stages for overall development. 
Therefore, overall development is the need of the hour for keeping physical, mental, economic and spiritual health. They are the factors of happiness. The scientists have arrived at conclusion that the following hormones in the body keep us happy-

1)   Dopamine- Secretion of this hormone takes place when we consume tasty food items and do favorable works. 
2)   Serotonin- It makes an impact on the capacity of sleep, hunger, memory, learning, etc. Its secretion takes place during running, meditating, walking, swimming, cycling, etc. 
3)   Oxytocin- It’s also known as love hormone. Its secretion takes place during hugging, praising, playing with children and helping someone with no self-interest. Mother feeds her child due to his hormone. 
4)   Endorphins- It’s painkiller of the body. Its secretion takes place during laughing, exercising, etc.

Clearly, all the four hormones are the sources of happiness. They are associated with our health. Then question arises that what should we do to keep us healthy and happy?

We can remain happy and healthy by doing following works-
•    Walking
•    Exercising
•    Laughing
•    Consuming balanced diet
•    Meditating
•    Helping others
•    Sleeping properly
•    Increasing social network
•    Controlling stress
•    Believing in the ultimate power

If we do all the aforesaid activities in our life, we will remain happy and healthy. There are two obstacles in its path-

•    Laziness
•    Habit

We can get rid of these obstacles by keeping our goal in mind and trying to do it. Don’t do haste in this work and get discouraged.
Now question arises that what’s the bliss? This bliss is beyond health and happiness. Aanandmayakosh comes after annamaya, manomaya, pranamaya, vigyanmayakosh. We can find this aanandmayakosh on the path of the best. Those people who love can get temporal happiness. They fail to get bliss. Living in coordination is essential for getting bliss. The Ishavasyopnishad says that-

Ishavasyamidamsarvamyatkinchitjagatyamjagat I
Tena tyaktenabhunjitha ma gridhahkasyasviddhanam I

It means that the people should enjoy the worldly items with a sense of sacrifice. Self-realization is called bliss which is simplicity and awareness. The Mundak Upnishad writes that the weaker people (physical-mental-intellectual-soul) fail to get soul. Neither insane nor aimless people get this. Those who keep coordination among religion, science, sanyas and yog can get this bliss. 
Purification of body and mind and agility are the first and last criteria of being happy, healthy and blissful.