Your physical health can play a huge role in your spiritual health and vice versa. If one or more of your chakras are out of balance, then it will affect your spiritual energy. Once this is out of whack a long list of ailments—mental, physical, emotional and spiritual—can crop up.
Also, if you want to strengthen your psychic abilities and be healthier all around, you need to strengthen your energy centers. When your chakras are balanced you'll feel more at peace, have a clearer mind, feel more connected to Spirit, will be healthier and happier, and your intuition will be heightened.