Touching down after 211 days in space, two cosmonauts suffered from dizziness, high pulse rates, and heart palpitations. They couldn't walk for a week, and after 30 days, they were still undergoing therapy for atrophied muscles and weakened hearts.  Scientists discovered that at zero gravity, the muscles of the body begin to waste away, because there is no resistance. To counteract this, the scientists prescribed a vigorous exercise program for the cosmonauts. They invented a "penguin suit," a running suit laced with elastic bands. It was designed to resist every move the cosmonauts made, forcing them to exert their strength on a regular basis.

We often long dreamily for days without difficulty, but God knows better. The easier our life, the weaker our spiritual fiber, for strength of any kind grows only by exertion.