Have you considered that keeping yourself physically fit contributes to sustainability? Sure it does! Physically fit people have fewer injuries and ailments and therefore make fewer demands on the heath care system. They also are more able to continue to work for sustainability.
CHALLENGE: Design a personal fitness program appropriate for your age and current level of fitness. Be sure to include both aerobic activity and muscle-strengthening activities. You may also include stretching and toning, yoga, meditation. Do you need to address your diet or plan to get sufficient rest? Follow you plan for one week. Do you notice any changes? Is your plan working for you, or do you need to make adjustments?
COMPLETING THE CHALLENGE: I am going to the YMCA for three classes every Tuesday and Thursday: Step Class (which is aerobic), followed by a beginners' level Pilates class (which is challenging enough for me!), and then a Bosu class (which is about balance and is really too easy for me, but since I'm already there....). In addition, I go to the gym once or twice each weekend with my hubby to use the machines (for muscle-strengthening) and then use the statinary bike (more aerobics). When we finish, we are usually ravenous, so we stop at the pizzeria.
Yes, my plan is working for me! I have more energy, feel more optimistic, am gaining strength and (gradually) losing weight.