Sun (Surya) and Ascendant (Lagna) decide our immunity and physical strength. Our endurance, prana energy, and ability to fight diseases can be known by the significance and strength of Surya and Ascendant. Both have an important role in developing our agility and physical constitution.
In any horoscope, the Sun is the tanu(self or body) karaka. Sun is the king of all planets and represents spirit. It is the chief source of life and offers resistance power. Sun lends us energy and vitality. Our determination to bounce back from diseases depends on the strength of the Sun. When the Sun is well placed in the horoscope, it makes the body strong and robust. When the Sun is benefic, it gives us the willpower to fight back diseases. But a malefic or a malign Sun makes our body weak and prone to various ailments.
Sun is a masculine and fiery planet. It has Agni tattva. This tattva represents inner fire and controls digestion. Agni tattva gives us strength and stamina and represents our energy to heal. Agni tattva signifies our capacity to handle physical pain. If the Sun and the Ascendant are not well placed, we cannot handle the pain and face too many struggles while recovering from diseases.
The combination of the benefic Sun and the Ascendant makes us strong and physically fit. Generally, athletes, bodybuilders, sports persons, and physically fit people have a benefic and strong Sun in their birth chart.The position of the Sun in different houses cast its own peculiar effects on our health and well-being. Sun placed in houses 6, 8, and 12 can give us a weak body and debilitate our resistance power. But it's not only the placement of the Sun that controls our health. Along with the Sun, it's the position of other planets too that affects our well-being. Planets that aspect or form angles with the Lagna strengthen or weaken our immune system.
Moon is watery in nature and has its domain over the mind. Moon controls our attitude and thinking and plays an important role in recovery. People born closer to Amavasya, or New Moon day, have a weak Moon. Such people are anxious and get startled easily. They fall sick very quickly due to their worrisome attitude. Their recovery will be slowed due to their pessimistic outlook.
Nakshatras, or lunar mansions, also play their due role in imparting health to the individual. Certain Nakshatras impart good health, while others prove detrimental to our overall well-being.Mercury rules the nakshatras of Aslesha, Jyeshtha, and Revati. Each Nakshatra is divided into four parts called quarters or padas. Those born with the Moon in the fourth quarter of Aslesha, Jyeshta, and Revati will have the weakest physical strength. Similarly, Ketu controls Ashwini, Magha, and Mula. Natives born with the Moon in the first quarter of these three nakshatras will have the weakest physical strength.