If exercise feels harder than it should, chronic stress may be working against you. Learn how to regulate your physiology so ...

Working out doesn't just build muscle but, in later life, helps maintain a powerful cellular machine that repairs damaged ...

Medically reviewed by Michael Menna, DO Key Takeaways The circulatory system carries oxygen and nutrients throughout the body and removes waste.The lymphatic system helps fight disease by creating and ...

Skeletal muscle is the type of muscle that controls movement. Problems with these muscles can be minor, life-threatening, or ongoing problems that make it hard to perform basic daily activities.