Alicia Birky, physical therapist: The CDC recommends 150 minutes of moderate-intensity exercise per week. Moderate-intensity exercise is when the activity feels somewhat challenging, but you can still complete it without stopping.
This 150 minutes also includes strength training twice a week. Strength training doesn’t have to involve dumbbells. It can be bodyweight exercises, resistance bands, or machines at the gym. If you're exercising in water, you can use the water’s resistance as well.
If strength training is new to you, don’t start with a 30-minute session. Start with 10-15 minutes, and track how you feel in the days following. Make adjustments as needed.
Start light – aim for 12-15 reps of each exercise. Listen to your body and pay attention to how you feel. You should feel tension in your muscles, but it shouldn’t hurt your joints.