We have about 650 +30/-20 muscles depending what expert you ask, i.e. how the groups. For us more mortals this is irrelevant.
When we wake up all of our muscles want new nutrients, oxygen and a way to get rid of the waste. We can help by commanding our brain to stimulate our muscles. We can do this all even without leaving our warm bed and it is free!
Exercising is the process our oldest part of the brain has managed already up to 600 million years. It has been honed to perfection using countless control an feedback loops. This ancient part of our brain keeps us alive by forcing heart to beat, lungs to breath, food to be processed to nutrients, and waste to be removed from the body. It is now totally automated process that works even if one has bocome unconscious.
To keep our physical body in good shape we must somehow move our muscles to secure that they all get nutrients and oxygen they need. Letting the brain always decide how this all is done is not the best solution for the aging people. However, it is perfect for the young and growing children who seem to be always on the move.
Our brain is well aware of the economy of all physical moves we make. Here its responsibilty to the nature is the survival of the species and the economic part does not include survival of the individuals that have aged beyond their clear usefulness to the species:
The brain keeps on learning throughout our lives leaving us to maintain our physical body, the host of the mind/brain unit. In our case this means also proper food supply that contains a multitude of minerals and virtamins (more here).
To keep our body fit we must exercise regularly one way or the other. The brain takes care of the exercising activities for children but as adults we have to do this ourselves. When in our 20's what we can do is not fit those who are in their 70's and 80's. But when we age tables are reversed and if our brain still works like it can do we have an edge with our life woth of knowledge and plenty of time to ponder how the past knowledge might fit to the different world of today.
The physical exercise gets more importants when we age. Some feel that the exercise is most effective when done early in the day like in the morning immediately when we open our eyes.
Surprisingly it also works like melatonin during the nights when the sleep seems to escape us. Going through the exercise routine while laying in the bed times will likely do the trick and one will fall asleep during or just after completing their own exercise program (no need redo when you wake up).
It is best to do exercises slowly and deep exactly like cats and dogs when they stretch up their body. A proper length for one exercise is from 1/2 hour to 3/4 hour.
The guidelines for a personal program are below but all details are up to you - what to include and what to exclude. The main purpose is to get each of the 650+/- muscles and muscle groups stretched and contracted 5 to up 10 times during the program.
Here is an outline, what fits to you is your decision - what does it matter if the cat is balck or white if it catches the mouse?
That is enough to keep you fit to your old age...
Of course you can also swim, walk, run, lift weights and do even the demanding 8/20 interval exercises. But if you just do the above you are not stressed at all while you will get fit.
To lose weight the only working program on this planet earth is reduced caloric intake. It helps if one cuts all sugar (and artificial sweeteners out).
Mosst people fail all their weight loss programs as they forgot the all deciding caloric intake. This fails as they let their brain control their mind and not the other way around (the impact of caloric intake to a persons weight was proven beyond doubt during the WW II).