Endurance training improves metabolic health by promoting the development of new blood vessels. Resistance training builds muscle, and a study recently published in the journal Medicine & Science in Sports & Exercise suggests the effort can also leads to small vascular adaptations.

Researchers assigned 36 males in their early 20s to a 12-week resistance training program. Some received protein supplements while others got a placebo. Weight training increased muscle fibers, with greater gains seen in the protein supplementing group.

After the second week of training, the capillary to muscle fiber ratio increased significantly, suggesting blood vessel development took place along with muscle growth.