Rubber is nonporous, so rubber footwear doesn’t allow your skin to breathe and it traps heat, keeping the feet very warm.
There are 250,000 sweat glands on your feet so you need to wear breathable footwear. If you don’t the sweat will not dry leading to fungus growth on your toes and clogged sweat glands.
There is another very important reason why you must not wear rubber on your feet. Pressure points connected directly to your organs are situated on the soles of your feet. If you do not keep the soles of your feet healthy and comfortable you are debilitating those pressure points thus weakening your organs.
Heat built up in the body due to over-work, tension and anger leaves the body through the feet. This is one of the reasons it feels good to put your feet on a cold stone floor or in a tub of warm salt water (depending on the climatic temperature). In a couple of minutes of doing this you feel relaxed. Pent up stress being released from your feet is also the reason why traditionally jewelry for the feet was mainly made out of silver, which is cooling, calming and anti-inflammatory. By wearing rubber foot wear you are caging the stress in your body.
So try to wear foot wear of leather, cloth or plant matter. Today most foot wear comes with rubber soles lined with leather, cloth or plant matter. These are practical as the rubber makes the foot wear non-slip. If you are wearing this kind of footwear I would suggest walking on a stone floor barefoot as often as you can. If you have a tiled floor at home or office get 1 stone tile and place it on the floor where you sit the most, take off your slippers or shoes and place your bare feet on the stone as much as possible. I am fully aware that it sounds irrational BUT most diseases, mental and physical are due to built up toxins in the body. Try it for a week and you will feel less tired, physically and mentally.