Final answer:
The measure to determine safe exercise conditions in the cold factors in the risk of hypothermia and involves calculating heat transfer through conduction, convection, and radiation, taking various environmental and individual factors into account.
Step-by-step explanation:
The measure used to determine whether it is too cold to exercise is not explicitly named in the provided information; however, decisions about exercising in the cold typically involve understanding hypothermia risk, considering ambient temperature, and using common sense to prevent health risks associated with exposure to cold environments.
In order to analyze the risk of hypothermia, you could construct a problem that calculates the rate of heat transfer from the body using methods of conduction, convection, and radiation. Factors to consider include size of the person, type of clothing, initial metabolic rate, sky conditions, amount of water evaporated, and volume of air breathed. This would provide an indication of how much physical activity would be required to maintain a safe body temperature in cold conditions.