Turning up the thermostat may help manage hypertension, according to a study that has found a link between indoor temperatures and blood pressure. Comparing blood pressure readings of people in their own homes with temperature readings, the researchers found that lower indoor temperatures were associated with higher blood pressure. "Our research has helped to explain the higher rates of hypertension, as well as potential increases in deaths from stroke and heart disease, in the winter months, suggesting indoor temperatures should be taken more seriously in diagnosis and treatment decisions, and in public health messages," said Stephen Jivraj, from University College London in the UK. "Among other diet and lifestyle changes people can make to reduce high blood pressure, our findings suggest that keeping homes a bit warmer could also be beneficial," said Jivraj. The researchers found that every one degree Celsius decrease in indoor temperature was associated with rises of 0.48 mmHg in systolic blood pressure and 0.45 mmHg in diastolic blood pressure. Ideal blood pressure is considered to be between 90\/60 mmHg and 120\/80 mmHg.The research team interviewed subjects with a questionnaire covering general health and lifestyle factors. Afterwards, nurses followed up by visiting 4,659 participants in their homes, to measure their blood pressure and to take an indoor temperature reading in their living room. The researchers accounted for potential confounding factors such as social deprivation and outdoor temperature to identify an independent association with indoor temperature. They found that average systolic and diastolic blood pressure were 126.64 mmHg and 74.52 mmHg, respectively, for people in the coolest homes in the study, compared with 121.12 mmHg and 70.51 mmHg, respectively, in the warmest homes. The research team found the effect of indoor temperature on blood pressure was stronger among people who do not exercise regularly, suggesting that physical activity could mitigate the risk of living in a cool environment and that people who do not exercise need to keep warmer to manage their blood pressure. "We would suggest that clinicians take indoor temperature into consideration, as it could affect a diagnosis if someone has borderline hypertension, and people with cooler homes may also need higher doses of medications," said Hongde Zhao of UCL. The findings suggest that adequately heating homes during the winter months could help reduce the winter increases in hypertension and associated cardiovascular risks, particularly among those at heightened risk of high blood pressure such as older adults or people with a family history of hypertension. While the study did not identify a threshold for a warm enough home, the researchers suggest that keeping living rooms to at least 21 degree Celsius could be advisable for general health.