A combination of cardio training (endurance) and strength training is ideal. When you exercise, your heart rate should increase significantly for at least 30 minutes. The general rule is that you should aim for a heart rate that is 70 percent of your maximum heart rate. The maximum heart rate is 220 min your age.
Some examples:
– Walking briskly for 30 minutes (at at least 5 kilometers per hour)
– 1 hour of cycling at a reasonable pace
– 30 minutes of swimming
– 20 minutes of rowing
– 1 hour of fitness