While exercise is one way of getting heat in the body to fight against disease and keep the body healthy, there are other scientific methods like baths, fasting, etc., which not only keep the health of the body maintained, but also cure it in case of ailment.
While the effect of exercise does not always reach the inner-most organs of the body, baths on scientific lines, as suggested by Nature-cure, take their heating effects to those organs and purify them of their foreign matter.