According to an article in The New York Times, taking a blood thinner will not make a person feel colder than she would otherwise. In general, the blood's level of thickness, whether affected by medication or not, has no relevance to a person's experience of heat or cold.
The New York Times article states that individual perception of heat and cold varies significantly, with perception having more relevance to how hot or cold someone feels than the actual temperature does. Although blood thinners do not make people feel cold, blood circulation is important to the body's regulation of temperature, which is why blood circulation differs depending on the kind of climate someone lives in.
