I am approached, on a regular basis, by many people who enthusiastically state that they are fit. I always ask them this question-"Fit for what?" While my question to them may seem a bit flippant; that is not my intention. The concept of being fit varies from person to person; including myself. Someone who is into weight training, has a really great physique and can bench press 225lbs with no problem, may consider himself to be super fit. Another person may be into endurance training and may consider that his fitness level is superb; because he can complete a half-marathon in one hour and 20 minutes. The point I am making here is that fitness can be specific or it can be general.
Some people train specifically to develop the strength component of fitness, while others may concentrate on the endurance component; this may depend on their sport or their personal preference, as can be seen from the examples I gave above. There are also many people who are concerned with developing a general level of fitness. To develop a general level of fitness would mean that your body has the components of strength, endurance and flexibility in complete balance. As both a karate instructor and a personal trainer, I am more concerned with my students and clients developing a general level of fitness; unless I am training an athlete for a specific sport.
False Fitness
Unless you are a competitive strength athlete or endurance athlete, it would seem a bit ridiculous to claim that you are generally fit, because you can bench press 300lbs; yet you can't run a mile without turning blue in the face, or feeling as if you are under serious cardio arrest. Likewise, it is equally ridiculous to claim general fitness, just because you can run two loops of savannah; yet you are so weak that you can't lift up your grandmother's 60lb bag of flour and put it into the trunk of her car; if granny lifts it up for you, then you know it's time to put on your jock strap and hit the gym.
Health Related
From a health point of view, performing weight training exercises is going to help strengthen your joints, ligaments and tendons; it is also going to help you preserve muscle mass as you age, and help to keep you mobile. Remember, muscle is what moves the body from point A to point B. Performing cardio-type exercises like brisk walking, running, biking etc is great for strengthening your heart, lungs and arteries, which forms part of your cardiovascular system. Why do you think they refer to these exercises (running, biking etc) as cardio? In addition to all of the above, you should stretch on a daily basis to preserve your range of motion. Remember, old age is associated with a loss of range of motion.
Structuring your programme
I think by now, you get the idea that I would like you to structure your fitness programme to include some strength training, some endurance work and some stretching. I would like to suggest that you perform strength training three times per week and perform cardio training (running etc) four times per week, for at least 40 minutes in each session; ensure that you stretch everyday. Do all this and then come talk to me about your general level of fitness. Keep Training.