It’s that time of year when it gets cold again in Connecticut. In mid-November or early December, we often get a reminder to keep our thermostats no lower than 65 degrees Fahrenheit (or 18 degrees Celsius). In fact, landlords are required by law to keep the temperature in their buildings at at least 65 degrees Fahrenheit. Why is it so important to keep your thermostat turned on when it’s cold? A new research article that summarizes dozens of past studies shows that living in cold indoor temperature (CIT) can lead to health problems ¹. 

Cold indoor temperature can increase blood pressure 

CIT can lead to higher blood pressure. The reasons for this are interesting and complicated. One reason is that CIT interferes with sleep cycles that help regulate blood pressure. Another reason is that people living in CIT tend to eat more salt and eating a lot of salt raises blood pressure ^2,3. Biological research shows that salt helps some mammals (including humans) maintain a higher body temperature in cold climates ^4,5. For this reason, people develop more of an appetite for salty foods when they are cold for long periods of time. Unfortunately, eating too much salt in your diet can increase blood pressure and eventually lead to heart disease. 

Cold indoor temperature can lead to poorer sleep 

Sleep is important for both physical and mental health. As mentioned above, research has found that CIT can interfere with sleep cycles, which leads to lower quality sleep. Other studies have found that temperatures that are too cold make it more difficult to fall asleep. 

Cold indoor temperature can make older adults physically weaker 

CIT can lead older adults to become frailer. Studies show that adults living in CIT tend to have weaker muscle power and grip strength than those living in warmer homes in the same area. This is a problem because weaker physical strength makes older adults more vulnerable to falling and breaking bones.  

In sum, it’s important to keep your thermostat at 65 degrees or warmer when it’s cold out. The cold is more than just unpleasant, it can cause health problems overtime. Keeping your home warm will keep you and your family happy and healthy. If you rent your home and your landlord has not turned on your heat, please report it to the Bridgeport Health Department here to get help.   

1. Janssen H, Ford K, Gascoyne B, et al. Cold indoor temperatures and their association with health and well-being: a systematic literature review. Public Health. 2023;224:185-194. doi:10.1016/j.puhe.2023.09.006 
2. He J, Whelton PK. Commentary: Salt intake, hypertension and risk of cardiovascular disease: an important public health challenge. International Journal of Epidemiology. 2002;31(2):327-331. doi:10.1093/ije/31.2.327 
3. Saeki K, Obayashi K, Tone N, Kurumatani N. Daytime cold exposure and salt intake based on nocturnal urinary sodium excretion: A cross-sectional analysis of the HEIJO-KYO study. Physiology & Behavior. 2015;152:300-306. doi:10.1016/j.physbeh.2015.10.015 
4. Dejima Y, Kim SW, Kashiwazaki H, Suzuki T. A spontaneous increase of salt intake and changes of colonic temperature in mice exposed to cold. Appetite. 1991;16(3):169-191. doi:10.1016/0195-6663(91)90057-Y 
5. Dejima Y, Fukuda S, Ichijoh Y, Takasaka K, Ohtsuka R. Cold-Induced Salt Intake in Mice and Catecholamine, Renin and Thermogenesis Mechanisms. Appetite. 1996;26(3):203-220. doi:10.1006/appe.1996.0016