Good morning,

As we (hopefully? finally?) transition from winter into spring, we find that we enjoy even slightly warmer days than we have been experiencing, even if the same temperature is enjoyed less at other times of the year (for example, as autumn cools into winter).  Why should a 50 °F day be perceived differently, at different times of the year?

Part of the answer has always been assumed to be psychological:  we evaluate new conditions relative to what we have recently experienced, and warmer days in the spring are enjoyed relative to the recent, cooler temperature of winter.  Increasingly, however, evidence is growing that suggests a physiological component, based on relatively gradual acclimation to prevailing temperatures over a longer term (weeks, months, or longer). 

These data suggest that long-term physiological responses to temperature gradually shape our vasoconstriction and blood delivery to the surface (you knew there was a link to our current lecture topics!), as well as our sensitivity and tolerance to temperatures below and above our 'comfort zone'.  This is part of a systemic response:  our peripheral blood delivery is altered, our sensory systems modulate their responsiveness to temperature, and our minds reduce expectations of a quick change back to more moderate temperatures (which reduces disappoint when temperatures remain extreme). 

https://www.nytimes.com/2018/10/24/science/human-bodies-cold-weather-adjustment.html

So, the next time you are enjoying a bit of sunshine on a brisk Spring day, remember that the pleasure of it is not 'all in your head' - some of it is in your skin, and your arterioles, and your hypothalamus, and your skeletal muscles, ....

Happy Spring -
Dr. Nealen

Good morning everyone,

I'm passing along here a reminder of the dangers of hypothermia and frostbite, which includes description of some of the physiological challenges extremely cold temperatures place on the body.  Seems appropriate this week!

https://www.nytimes.com/2019/01/29/health/frostbite-hypothermia-cold-weather.html

Just remember, Spring is only about 7 weeks away ;-)
Dr. Nealen