Different types of exercise can significantly affect heart rate. Aerobic exercises, such as running, cycling, or swimming, typically elevate heart rate for extended periods, improving cardiovascular endurance. In contrast, strength-training activities may cause intermittent spikes in heart rate depending on the intensity and rest periods between sets. High-intensity interval training (HIIT) is particularly effective at increasing heart rate rapidly, improving fitness levels quickly. Monitoring heart rate during various exercises can help individuals gauge intensity levels and manage their fitness training for optimal performance and health benefits.