Many older individuals rely on treadmills to get their recommended 150 minutes of moderate-intensity exercise each week. Aside from being readily available, treadmills offer the benefits of targeting key muscle groups (quadriceps, calves, glutes, and hamstrings) that older adults need to strengthen in order to improve their balance and endurance. These exercise machines can also be immensely helpful to those recovering from surgery or injury, based on the guidance of a physical therapist. While many treadmills gauge the exerciser’s intensity with hand sensors that monitor heart rate, the better way to gauge exercise effort involves ranking how strenuously the exerciser is working (on a scale of 1 to 10). A rate of 5 to 7 is consistent with moderate-intensity exercise.