For children with asthma, how warm or cool their home is, particularly their bedroom, has a small but significant effect on their lung function, according to research conducted in New Zealand.
After collecting daily measurements of lung function and hourly recordings of indoor temperature, researchers discovered that, below a threshold of 9°C (~48°F), every 1°C (33°F) increase in temperature would result in a 0.010 L/s improvement in Peak Expiratory Flow Rate (PEFR) in the morning, and a 0.008 L/s improvement in the evening.
Meanwhile, FEV1 improved by 10.06 mL in the morning for every 1°C increase below a threshold of 12°C (~53°F), and by 12.06 mL in the evening for every 1°C increase in temperature up to 10°C (50°F).
“Better metrics for measuring indoor temperature exposure will help guide estimates of health benefits that can be realized from improving the indoor environment,” the authors concluded. They noted that the current or previous day’s temperature was suboptimal for this purpose. “Instead, we suggest measuring indoor temperature over a longer period and subject to a local threshold similar to those used for outdoor studies.”