Biking in a vigorous spinning class can burn between 358 and 715 calories in 45 minutes, according to Discovery Health. A spinning class also has the benefit of strengthening many muscles in the lower body, including the glutes, thighs and calves.
Spinning class rates on the higher end of the efficiency scale of calories burned per hour, states Discovery Health. Other popular classes, such as yoga or Zumba, burn about 500 calories or less per class.
Metabolic rates affect the number of calories a person burns when engaged in physical activity, as the Mayo Clinic explains. The size and amount of muscle mass and fat on a person affects the speed of their metabolism and the number of calories they burn during exercise.