Changes in coordination are less related to muscles and more related to your brain and nervous system, everything in your brain needs to be coordinated together in order to do basic things like holding something steady while you walk, and move things in an accurate motion. As you get older you actually produce less and less dopamine which slows down your movements and reduces your coordination even without having parkinsons. Also as you get older naturally your eyes start to fade and vision is a very important aspect in coordination, hence 'hand eye coordination'.
Now how to improve your chances to prevent these and the earlier the better with these items:
• Aerobic exercise is the save all in helping your bodily functions as you age so this is definitely on the list.
• Do exercises that help in balance for example; yoga, pilates, isometric weightlifting and workouts that help your flexibility.
• If you plan on playing any sports as you age, like golf or tennis then play those sports casually as you get older whenever you have the time so you can develop muscle memories.
• Fuel your brain and muscles with healthy foods that are shown to have benefitial effects on aging such as; fish, avocados, fruits, vegetables, whole grains and other foods that you would expect to have healthy effects.
• Sleep well, sleeping is always a good way to keep your daytime self healthier.