The answer to the question depends on the type of exercise. Would you like to do things you have not done in years? Do you want to have a lower blood sugar level, lower blood pressure, increased cognitive function,higher testosterone level, increased human growth hormone, less body fat,improved posture, increased maximum oxygen uptake, increased bone density, a higher resting metabolism, more lean body mass, and increased resistance to disease and injury?
Would you like to eliminate back pain and nagging injuries? It would be nice to lessen arthritis pain, sleep better, and have an overall feeling of well being. All of that is possible and will not require hours out of your week if you perform exercise that produces the highest marginal return for the effort and time spent – namely HIIT, high intensity interval training for strength.
Add to that, a sensible eating plan you can stick to. Then do something you enjoy – running, ride, yoga, or walking the dog. If you are so inclined add sprint training. In total, sprint and HIIT, it takes me about an hour and half of my week. Your free time need not be spent in drugery.
Improvement on some of the above measures can make all the difference – avoid a herniated disc, a frozen shoulder, or type-2 diabetes or wall away from a fall unjured. Even if you improve just a bit on all the measures, collectively that can be huge.