Heart :

During the stress response, you breathe faster in an effort to quickly distribute oxygen-rich blood to your body. If you already have a breathing problem like asthma or emphysema , str...

Veins return blood from the body to the heart, so the blood can be recirculated. To return blood to your heart, the veins in your legs must work against gravity.

Structural aspects in pumping the blood to heart-

• Muscle contractions in your lower legs act as pumps
• Elastic ...

In order to supply your body with enough oxygen to maintain functioning, your heart must work harder. You will have an increased heart rate and greater force per beat. Your body creates more oxygen-carrying red blood cells, which is generally helpful.

However, it also thickens your bloo...