As is usually the case with numbers like this from the past, this is a mean value, not a median value, that is massively skewed downwards by having upwards of 50% child mortality by age 4.

A typical Swiss person in 1875 who had already turned 30 could be expected to live to be 70.

Here's an article talking about this phenomenon [0]. They term it "adult modal age at death", i.e. at what age do people tend to die once they have survived childhood? In Sweden, in 1875 an adult woman could be expected to live to be 72, and an adult man to be 69. But the average life expectancy in Sweden in 1875 was only 44.

Per the same article, the modal age at death for adults in Switzerland in 1875 was 70 for both men and women.

[0] https://www.cairn-int.info/article-E_POPU_1204_0683--the-mos...

As well as in the lowlands, far enough away from the sea to not have easy access to produces or sea salt through trade. It used to be common in the english midlands and the US midwest (as well as the appalachia and rockies).