Fasting during Ramadhan doesn't mean you should end up lying down in your bed and being lazy all day long. You should be moving as usual!
Simple and basic exercise during Ramadhan will benefit our body 2 to 3 times better than our normal day. This is because our body lacks nutrients and water in which it needs in order to generate energy.
With the lack of energy, it will use its own energy supply. This will cause you to become tired at a faster rate but your cell will develop itself by eating up energy from fat in your body. Even water will be sucked from the fat itself.
For beginners, you can try jogging for 15 to 30 minutes at a very slow pace to get use to the condition. Don't get excited and run around nonstop as your body will suffer from shock and this will lead to a more serious matter. Start slow as this will improve your cardiovascular ability before carrying on with a more intensive exercise.
After several sessions of jogging and you feel confident to carry on, try static muscle stretching to get your joins and muscle join the fun and develop. Joints and muscle require a lot of water to work perfectly and with the lack of muscle, they can become quite stiff and you might feel some pain. If you do, stop doing anything, sit down and rilex. Don't worry, because this will only happens for a few starting session and the pain will go away after you rest.
After you feel better at jogging and feel it won't pose any problems to you, you are now ready to carry on with more intensive activity such as playing football or tennis. Be careful not play too hard as usual as your body is not used to the condition just yet. It will take about a week or two to get use to fasting condition.
For food, consume more water and more carbohydrate (rice, bread) to supply yourself with enough nutrient for a day routine.
Hope that will help you in getting through Ramadhan with healthy lifestyle.