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exercising while not eating is a bad idea. besides that fasting wont heal your shoulder. maybe try physiotherapy

From my experience light exercise is not harmful (to me). Heavy cardio and anything that would lead to heat exhaustion are the most dangerous. Also I should clarify that by "shoulder exercises" I mean shoulder motions that work the different muscles in the shoulder as well as some exercises with a resistance band. These "exercises" would be akin to physiotherapy exercises. I'm not talking about dumbbell presses. I think you misunderstood what I said or it was my fault for not being clear. Also, If I have some inflammation in my shoulder and fasting is known to be anti-inflammatory, wouldn't a combination of these exercises and fasting be a beneficial combination? Why would it not, I'd like to see the facts that your basing your comment on.