The British thermal unit (BTU or Btu) is a traditional unit of work equal to about 1055 joules. It is the amount of work needed to raise the temperature of one pound of water by one degree Fahrenheit (Physical analogue: one four-inch wooden kitchen match consumed completely generates approximately 1 BTU).
Blisters on feet can be caused by numerous things, including: 1  Forceful rubbing or friction on the foot. 2  Bone spurs or exostoses. 3  Burn. Freezing.  Chemical 1  exposure. Infection.  Allergic 1  reaction. Pinching  skin. Medical 1  condition. Foot perspiration.  Fungal infections such as Athletes foot.
Blisters tend to occur more often when the skin is sweaty and slipping around, which is why we seem to get more blisters in the summer. However, ill-fitting shoes also cause painful blisters. If your high-heeled shoes cause your feet to slide down to the front, putting pressure on your toes, chances are you're going to get some friction against the heel as you walk.