The weight gain sparked concern among researchers who said further studies are needed to gauge the long term effects.

VOA: standard.2010.07.08

The long term effects of breathing polluted air are even more alarming.

VOA: standard.2010.08.04

Researchers studying the effects of long-term spaceflight often examine the hipbone or backbone.

VOA: special.2009.03.10

Long-term use can produce unwanted effects in some people.

VOA: special.2009.04.07

The Mars-500 mission at Moscow's Institute of Biomedical Problems will test the psychological and physical effects of long-term isolation on humans.

VOA: standard.2010.06.02

Also on board is a new exercise machine, which is part of ongoing studies into the effects of long-term space flight on muscle and bone loss in astronauts.

VOA: standard.2010.04.05