What are clear fluid filled bumps on chest and abdomen after exercising?

Unfortunately I have the same symptom. I thought they were caused by sun exposure, but they started to appear any time my body got over heated - such as working out-. I think they are millia, like the small baby acne, but secondary millia which is caused by sun damage and I guess is highly reactive to stress on the body. That really bumms me out because I don't want to think about having severe skin damage.