Cold winter air holds less moisture than warm air, while at the same time artificial heat causes evaporation of moisture from your skin and nails. As a result of reduced ambient humidity and artificial heating, cuticles and nails become much dryer and more fragile.
When the cuticle is chronically exposed to dry conditions, while at the same time also intermittently immersed in water (e.g. doing dishes), significant damage can occur. The repeated cycling between wetting and then drying the fingers causes loss of adhesion between the cuticle cells. Degradation and loss of the cuticle leads to a condition called paronychia or inflammation around the proximal part of the nail (the base where it begins to grow).
In addition, the normal nail plate (the nail itself) holds about 15% water vapor. Under very dry conditions the percentage of water in the nail falls below 15%, which can lead to roughness of the surface of the nail plate and peeling. Another effect can be splitting of the nail into layers.
This cuticle creates a seal which helps protect the nail pocket from infection and irritants. Disturbance of this seal can lead to damage of the nail matrix, which is the machinery responsible for producing your nails. As a result, you may experience reduced or irregular growth of nails and deformed nails (including pitting, ridging and splitting).
Overnight gloves with moisturizers and oils can help to hydrate and nourish your cuticles and nails making them more resilient to dry ambient conditions. Through a process called occlusion, gloves improve the penetration of topical products into the nail cuticle and nails. This maximizes the amount of product that is absorbed.
Basic nail care only requires a gentle soap, water and moisturizer.
I like thick hand creams like the Norwegian Formula Hand Cream by Neutrogena. This can be applied under cotton-glove occlusion nightly to improve efficacy. Any glove should be breathable if worn overnight, as too much moisture can be as or more damaging than too much dryness. I also recommend daily multivitamins with biotin, zinc and vitamin D, as our nails reflect our overall health and nutrition and certain vitamins and minerals are necessary for nail growth.