There has never been a power cut in human body! There has never been a lock-out in the chemical and mechanical factory within! You see this marvelous machine has taken millions of years in making with perfect balance to be maintained between so many inter-related processes and parameters, which will be difficult even by your most advanced computing power, that too using minuscule power and resources without any pollution!
Such a great machine is abused day and night creating difficult to repair imbalances in several inter-related parameters. You can’t ignore one part of this temple while you take all the care for another part because it is one machine – not separate. Any abuse by way of eating wrong foods or wrong breathing pattern or over exercising or drinking less water or wrong sleeping posture – everything affects the entire machine structure and its overall balance.