Is it true if a guy holds his urine too long it can damage the prostate and make it harder if not impossible to have boners or be aroused?

Lately, I've come to realize that I have a very powerful tendency to fall asleep in class. It seems that I can't stay awake in any lecture style class where I have to listen to the professor and take down notes — where there is minimal engagement on my part. I've pretty much fallen asleep in all of my lecture classes, during one part or another for the whole semester. I think I'm getting regular sleep — six hours at a minimum. I don't like to drink coffee or anything.

The demographic transformation in our society resulted from better living conditions and improved health status. Why should we promote health when long life spans only create health, economic, and social problems for us?

Is it dangerous to wax or use a chemical depliatory such as Nair on areas of the skin that have moles? I've seen warnings on some labels regarding this. What could happen to the moles?

I desperately want to attend school in NYC, but have one reservation. I'm asthmatic and I'm afraid that my asthma will be worse in a big city. I traveled to NYC for a week this summer and was fine, but have heard it could be worse in the winter. Can you advise me? I so don't want to let my asthma limit my dream of going to school in NYC.

Why is it that when a person vomits, it causes others to vomit — even when they don't have an illness causing it? Is this something triggered by the brain or is it something that happens by reflex (survival instinct) for someone to vomit since, perhaps, what the first person was eating may affect the second who vomits as well?

1) I read the information on your website about knuckle cracking, and I was wondering if it applies to cracking backs and necks. I know that people often have their backs cracked by friends, etc. because it feels good and seems to relieve tension. Also, when my neck feels tight, I often turn it from side to side until it cracks and feels better. I've heard that chiropractors do some version of this, and call it "realignment." Is this safe? Is there a right or a wrong way to crack a back or neck? Is cracking your back/neck actually therapeutic in some way?

2) As a college student, I sometimes spend long hours reading books or looking at computer screens, and often my neck gets stiff. Like many of my joints that get stiff, sometimes I crack my neck, like I would crack my knees or fingers when they feel stiff. I often wind up doing this several times a day.

My question is, could I do irreparable damage to my spinal system if I continue using this method to soothe a stiff neck? Could I wind up a paraplegic if I continue to crack my neck? Leak spinal fluid, etc.?

I've been eating the yogurt Activia and have felt less stomach grumblings since. I switched to just a low-fat yogurt for cost reasons and have had the grumblings come back. Is Activia really better for digestion or is this all in my head?