Read here. Over several decades, global minimum temperatures have increased. Daily temperature average is calculated using the daily minimum and maximum temperatures. If the minimum temperature is increasing, then the daily average will also increase. (At the same time, the difference between daily maximum and minimum temperatures is shrinking. Diurnal Temperature Range (DTR) = the difference between a day's maximum and minimum air temperature.)
Chinese researchers found that as the minimum temperature increases (DTR decreases), there resulted in substantially less elderly deaths caused by coronary heart disease.
"And since it has long been known that the DTR has declined significantly over many parts of the world as mean global air temperature has risen over the past several decades (Easterling et al., 1997), it can be appreciated that the global warming with which this DTR decrease is associated (which is driven by the fact that global warming is predominantly caused by an increase in daily minimum temperature) has likely helped to significantly reduce the CHD mortality of the world's elderly people."