Unfortunately there is no evidence that sleeping in a bra has any affect on the 'perkiness' of your breasts. If your breasts are in good shape it is because of your genes, not your bra. Breast sagging is related to many factors - the softening of tissues and ligaments with age; the general composition and fat content of the breasts; rapid weight gain (like during pregnancy) that can stretch the skin. A well-fitting bra and good posture can give you the best shape for the longest time but even these won't stop your breasts from sagging over time if the other factors are present. Sleeping in an underwired bra not only damages the bra, the wires can damage the breast tissue. The strong elastic can affect your breathing and circulation. If you insist on sleeping in a bra I suggest you find a comfortable, supportive non-wired bra and use it for sleep only.

I am 63 and have really perky breasts. I spray them daily with cold water and do the following exercise: clasp hands together and push, do around 50 repetitions.

Make sure you get remeasured for a bra every time you go to get a new one, or every 6 months. Buy bra's with proper support in them that wont irritate your skin and make you scratch, damaging the tissue around your breasts. Also, never go without a bra if you can help it! Moisturise with a good moisturiser every day; if you start doing all of this from a young age then you could really prevent the effects.

Its a two pronged attack: I sleep in the soft cotton nursing bras I bought when I was breastfeeding - (they are like really soft sports bras) and I also end every shower with a blast of cold water right on my chest. I am a D cup and not exactly pointing to the stars, but not looking all that bad either!

Press ups - either box or proper. Chest press either at the gym or on your work out mat at home with some handweights. Boxercise.