long lasting:http://www.telegraph.co.uk/finance/property/green/9695896/Eco-living-The-mattresses-that-last-50-years.html

arthritis etc:http://www.organic.org/articles/showarticle/article-204

 

Synthetics vs. natural materials: 

 

exem, sleep:http://www.telegraph.co.uk/finance/property/green/9831714/Eco-living-could-wool-bedding-help-you-sleep-better.html