Stimulants increases the heart rate and palpitation. These drugs improve work output ability by reducing the feeling of fatigue. They tend to increase alertness and physical activity. It increases the heart rate and reduces the reaction time. Examples of these are caffeine, amphetamines. They are used to increase endurance and speed. Steroids are very strong chemicals which are used by the players during training period. They increase the heart rate, body weight, muscle mass and blood circulation. They promote growth and healing process. By increasing muscle size and strength, athletes enhance the performance in sports. Steroids are either taken orally or by intra muscular injection.
