Factors which increase our awareness of clothing can lead to discomfort and may be the direct cause of it. Pressure of the fabric of a garment on the skin is one factor which is often related in this way and it has been proposed that, in this respect, discomfort arises when this pressure approaches that of the diastolic blood pressure. Similarly, wetness of skin is another factor closely related with comfort and it has been suggested that discomfort is particularly notable when three quarters of the body surface is covered with liquid sweat. Comfort is also associated with the ability of the body to maintain a constant core temperature not only under different environmental conditions but also at different work rates for the body.