why should we silently chart mantras before getting out from bed?

We have often heard people associating good sleep with happiness. It is often said that one who has lost sleep has lost all happiness of life. We have many sashtras regulating how to sleep and how to get up. The sashtras say that we should get up early in the morning during brahma muhurtha (ie around three or four)it is also said that sleeping during brahma muhurta will bring with it ill fate. so it is like one should get up ;turning towards his right, during brahma muhurtha and sit calmly and open up ;your palm and chant the following mantra silently.
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கராக்ரே வசதே லக்ஷ்மி
கரமத்யே சரஸ்வதி
கரமூலே ஸ்திதா கௌரி
ப்ரபாதே கர தர்ஷனம்.
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when a person is sleeping his heart works slowly for the purpose of blood circulation. when we jump drastically out of bed, then heart has work fast suddenly and there is a sudden burden in the heart. This will increase the heart beat rate suddenly. So to avoid this sudden burden to heart we should sit down calmly and tell some mantras so that the heart adopts to the work pace gradually not drastically and the rate of heart beat is balanced.

Statistics say that 23% of heart attacks have been recorded while getting up from bed