They were put on a rigorous 12 week exercise program. Dust mites are always a going concern. Make sure you wash linen, bedding, plush toys on a regular bases. Wash in hot water. Dust mites thrive in warm and humid places, so the number one most likely place to find these little critters is in bedding.
Dust can cause many problems for people that suffer from allergies.
Dust contains many allergens, so try to make your home as dust free as possible. Drapes, blinds, knick knacks to name just a few places, where dust collects. Pets cats are particularly the cause in animal induced allergies. The allergens caused by cats are in their saliva and skin. Some tips are to bath your cat at least once a week, and block off access to your bedroom if you are a allergy sufferer.