There are 3 things that relate to aging and every reasons starts with the letter “s”: the sleep, the sugar and the stress.

The lack of sleep killsdamages the brain, too much sugar increases red blood cells and thicken thes your blood, and stress suppresses hunger and do anhave other unpleasant effects.

Also, there are two effects: the placebo effect and nocebo effect - when humans think about positive and negative thoughts, respectively, thoughts, it iit becomes your reality.

So, be kind to yourself, and be positive with yourself!

There are 3 things that are related to aging, and every reasonsach of these starts with the letter “s”: the sleep, the sugar, and the stress.

Added a comma before the "and" to indicate the start of a new subject.

TheA lack of sleep killsharms the brain, too muca high sugar increasetake increases the amount of red blood cells and thickens the blood, and stress suppresses hunger and do ancauses other unpleasant effects.

Also tThere are twoalso two additional effects: the placebo effect and the nocebo - wheneffect, both of which influence the human thmind ink about positive andor negative manner, respectively, thoughts, it is your reality.

Restructured the second half of this sentence to make it flow more easily and to make it more clear on which of these effects you're attempting to define.

SoIn short, be kind to yourself, and be positive with yourself!

SSSALSO POSSIBLE: The Three "S"s

TPrimarily, there are 3three things that relate to aging and every reasonsach of them starts with letter “s”: the sleep, the sugar and the stress.

Suggestion #1: Add the hedge word "Primarily" since other minor factors also exist.
Suggestion #2: Small numbers such as "3" are usually spelled out in English

TheA lack of sleep killsimpairs the brain, too much sugar increase red blood cells and thicken the blood ,and stress suppress hunger and do ans well as other unpleasant effects.

Also there are twowo potential effects exists: placebo effect and nocebo - when humaneffects. When we think about positive andly or negative, respectively, thoughts, it is yly, these influence our reality.

There are 3 things that relate to aging, and every reasach onse starts with letter “s”: the sleep, the sugar and the stress.

The lLack of sleep kills the brain, too much sugar increases red blood cells and thickens the blood, and stress suppresses hunger and do ancauses other unpleasant effects.

Also there are two effects: the placebo effect and the nocebo effect - when human think abouts have positive andor negative, respectively, thoughts, it is you predictions, these thoughts are likely to become their reality.