When a person is submerged in cold water, their body temperature can drop very quickly.

This is because heat is transferred quickly, by conduction, from the warm body into the cold water. An experiment was carried out to see if it is better to stay still if you fall into cold water or try to swim.

• Two men sat for 30 minutes, in the air at a temperature of 15⁰C.
• They then got into the swimming pool, where the water was also at a temperature of 15⁰c,
• Person A swam for the next 30 minutes. Person B lay still in the water.

The body temperature of both men was measured at 10-minute intervals throughout the experiment. The results are shown in the graph.

Suggest why person A's temperature dropped faster than the person B's temperature during this time period.