http://www.humantouch.com/massage-chair-benefits.html make a series of claims regarding the health benefits from regularly using a massage chair:
Regular massage offers several measurable health benefits that help promote everyday health. By increasing circulation, your body can pump more oxygen and nutrients to tissues and vital organs, which promotes faster healing and a return to a health state. Regular massage also stimulates the lymph system – the body's natural defense against toxic invaders – to help avoid sickness and promote an overall sense of wellbeing. And massage prompts the body to release endorphins, the body's natural painkiller, easing sore, tired muscles.
Beyond physical benefits, massage helps reduce stress, anxiety and fatigue, and allow the body and mind to be better in tune. This is significant when considering both short- and long-term stress triggers changes in the body increasing the likelihood of getting sick, raising the risk of serious conditions like heart disease, and can make problems we already have worse.
In summary, the cumulative effects of regular massage can strengthen and tone the entire body to help prevent unnecessary strains and injuries that might otherwise occur due to excess tension. Never has something so comfortable, indulgent and convenient helped so many people feel better, play better and perform better.
I see that many of those claims are echoed on other popular health websites. Are they all true?
I am aware of Are there health benefits from traditional massage therapy?, but this question focuses on massage chairs.