Beginner Fitness Level: You do little to no exercise. Your strenuous exercise endurance is a few minutes. For your workout safety, you should begin with short bouts of light-moderate exercise (such as 10 minutes, 2x/day). Good options are water aerobics, walking, stationary bike, any light cardio, light strength training. Seek guidance from a personal trainer, exercise website, exercise video, group class, book, etc. Your goal should be to work up to 30 minutes per day, 3-4x/week.
Intermediate Fitness Level: You do occasional exercise at a moderate intensity. For your safety, be careful not to injure yourself with a new or overly strenuous workout. Try to exercise consistenly 3-5x/week in order to stay in shape. Try to challenge yourself progressively with higher intensity of exercise. 30 minutes should be your minimum workout time, and try to work up to 45 minutes. Appropriate workouts are light jogging, elliptical, swimming, Zumba, aerobics class, and strength training.
Advanced Fitness Level: You exercise vigorously at least 3-4x/week. You have good muscle strength and cardiopulmonary endurance. You usually work out for at least 1 hour at a time, and you could easily do more. For injury-free workouts, know your pain-tendency areas and be sure to strengthen and stretch them appropriately. Do not forget to take rest days. Be sure to vary your workouts with cross-training, intervals and plyometrics (pending sports activities). Drink sufficient water during your workouts. Do not push through an injury during training, sports or races. Train properly for all your athletics and races in order to avoid stress or overuse injuries. Otherwise, keep up the good work! If you are in this fitness group but need to lose more weight, you must increase exercise levels. This means increasing from 60 minutes/day to 90 minutes/day, modifying your workouts to boost your metabolism (such as weight training or intervals), or increasing your resistance levels.
Guru Fitness Level: You design your own workouts, and you are able to teach others. For your safety, remember that you are not exempt from workout injuries. Be sure to maintain balance between the muscle groups on the front and back of the body. Do not forget the importance of upper body, lower body and core strength. Use your knowledge to educate those around you with less exercise experience. Good goals for you are marathons, triathlons, fitness instructor certifications and/or exercise/sports competitions.