They start for at least a month.
If you are finding that your legs get so numb that you are unable to stand, you should see a doctor. It is normal to get numb legs from sitting for long periods of time but you should be able to stand up.
Any hard surface will cause you to tire if you stand upon it for a long period of time. Concrete is the most common problem as this is usually found in industrial settings where workers have to stand for long periods. Slate would have the same effect, but is not very commonly used in such settings.
While on birth control, your periods should last just as long as when you're not on birth control. Some women regularly experience 2-3 day periods while other women can regularly experience 6-8 day periods.
plants that can stand for long periods of time w/o water like cactus
5 hours
Not as long as you keep having them. If they are regular that is what is normal for you. If not they can be regulated.
You shouldnt need to purchase a cooling stand or a chill mat for your home office laptop unless it is used for excessive periods of time.
if you build on sand your house may fall-- but if you build it on a solid foundation it could stand for long periods of time.
No.
When you stand for a long time, it may cause your knees to buckle resulting in a vaso-vagal reaction. When this happens, there is a decrease in blood pressure which can make a person collapse or faint.
When the night has come And the land is dark And the moon is the only light we see No I won't be afraid No I won't be afraid Just as long as you stand, stand by me And darling, darling stand by me Oh, now, now, stand by me Stand by me, stand by me If the sky that we look upon Should tumble and fall And the mountain should crumble to the sea I won't cry, I won't cry No I won't shed a tear Just as long as you stand, stand by me And darling, darling stand by me Oh, stand by me Stand by me, stand by me, stand by me Whenever you're in trouble won't you stand by me Oh, now, now, stand by me Oh, stand by me, stand by me, stand by me Darling, darling stand by me Stand by me Oh stand by me, stand by me, stand by me
The starting AND ending of your periods. :)