According to WebMD, sweating is not an indicator of burning calories or exertion. The body is able to burn calories without breaking a sweat. Activities such like walking or even sitting burn calories, but do not necessarily cause sweat.
Sweat is the way that human bodies regulate and cool core temperature. Women's Health states that higher core temperatures do not mean that more calories are being burned. The fitter a person is, the less likely they are to sweat during physical activity. This is because the body of a fit person is conditioned better and it takes more to raise the core temperature and produce sweat.
Women's Health also states that if a person is sweating profusely 10 minutes into a workout, it does not necessarily mean they are unfit. Everyone is equipped with different amounts of sweat glands.